feat: remove checkerboard icon and change bottom toolbar

- "auto" is not essential for our hard fork, so i simply remove it.
- remove all useless code after removing it.
- enlarge the min size of window because previous may trigger bad layout when showing navigation view.

CMakeLists.txt

@@ -20,7 +20,7 @@ set (CMAKE_AUTOUIC ON)
 
 find_package(QT NAMES Qt6 REQUIRED COMPONENTS Core)
 
-set (QT_MINIMUM_VERSION "6.4")
+set (QT_MINIMUM_VERSION "6.5")
 
 find_package(Qt${QT_VERSION_MAJOR} ${QT_MINIMUM_VERSION} REQUIRED
     COMPONENTS Widgets Svg SvgWidgets LinguistTools
@@ -39,7 +39,6 @@ endif ()
 
 set (PPIC_CPP_FILES
     app/main.cpp
-    app/framelesswindow.cpp
     app/mainwindow.cpp
     app/actionmanager.cpp
     app/graphicsview.cpp
@@ -54,10 +53,12 @@ set (PPIC_CPP_FILES
     app/exiv2wrapper.cpp
     app/playlistmanager.cpp
     app/fileopeneventhandler.cpp
+    app/playlistscout.cpp
+    app/playlistscouts/qtscout.cpp
+    app/playlistscouts/explorerscout.cpp
 )
 
 set (PPIC_HEADER_FILES
-    app/framelesswindow.h
     app/mainwindow.h
     app/actionmanager.h
     app/graphicsview.h
@@ -72,10 +73,16 @@ set (PPIC_HEADER_FILES
     app/exiv2wrapper.h
     app/playlistmanager.h
     app/fileopeneventhandler.h
+    app/playlistscout.h
+    app/playlistscouts/qtscout.h
+    app/playlistscouts/explorerscout.h
 )
 
 set (PPIC_UI_FILES
     app/settingsdialog.ui
+    app/aboutdialog.ui
+    app/metadatadialog.ui
+    app/mainwindow.ui
 )
 
 set (PPIC_QRC_FILES
@@ -117,6 +124,11 @@ else()
     qt_add_translations(${EXE_NAME} ${ADD_TRANSLATIONS_ADDITIONAL_ARGS} TS_FILES ${PPIC_TS_FILES} QM_FILES_OUTPUT_VARIABLE PPIC_QM_FILES)
 endif()
 
+# YYC MARK:
+# This is essential, otherwise Qt UIC generated UI header file
+# can not find our header files if there are custom widgets inside UI file.
+target_include_directories(${EXE_NAME} PRIVATE app/)
+
 target_sources(${EXE_NAME} PRIVATE ${PPIC_QM_FILES})
 
 target_link_libraries (${EXE_NAME} Qt${QT_VERSION_MAJOR}::Widgets Qt${QT_VERSION_MAJOR}::Svg Qt${QT_VERSION_MAJOR}::SvgWidgets)

app/aboutdialog.cpp

@@ -18,7 +18,7 @@ static QString loadEmbeddedHtml(QString&& path) {
 }
 
 AboutDialog::AboutDialog(QWidget *parent)
-    : QDialog(parent), ui(new Ui::AboutDialog)
+    : QDialog(parent), ui(new QT_PREPEND_NAMESPACE(Ui::AboutDialog))
 {
     ui->setupUi(this);
     setWindowFlag(Qt::WindowContextHelpButtonHint, false);
@@ -35,7 +35,9 @@ AboutDialog::AboutDialog(QWidget *parent)
         .arg(tr("None of the operations in this application will alter the pictures on disk."))
         .arg(tr("Context Menu Help"))
         .arg(tr("Keep transformation", "The same meaning of MainWindow's Keep transformation."))
-        .arg(tr("Avoid resetting the zoom/rotation/flip state that was applied to the image view when switching between images."));
+        .arg(tr("Avoid resetting the zoom/rotation/flip state that was applied to the image view when switching between images."))
+        .arg(tr("Checkerboard", "The same meaning of MainWindow's Checkerboard."))
+        .arg(tr("Checkerboard light and dark theme can be adjusted in the configuration window, or easily switch it by holding Shift and clicking the button."));
 
     const QString APP_NAME_ARG = qApp->applicationDisplayName();
     const QString APP_VERSION_ARG =

app/aboutdialog.h

@@ -7,7 +7,6 @@
 
 #include <QDialog>
 
-
 QT_BEGIN_NAMESPACE
 namespace Ui {
 class AboutDialog;

app/actionmanager.cpp

@@ -4,7 +4,11 @@
 
 #include "actionmanager.h"
 
+#include "settings.h"
 #include "mainwindow.h"
+#include "playlistmanager.h"
+#include "graphicsview.h"
+#include "graphicsscene.h"
 
 #include <QGuiApplication>
 #include <QSvgRenderer>
@@ -25,6 +29,8 @@ void ActionManager::setupAction(MainWindow *mainWindow)
 {
     // region: Action and Its Icon Creation
 
+    // Declare some convenient macros and lambdas.
+
     #define ICON_NAME(name)\
         QStringLiteral(":/icons/" #name ".svg")
 
@@ -39,40 +45,51 @@ void ActionManager::setupAction(MainWindow *mainWindow)
         w->addAction(*a);
     };
 
-    #define CREATE_NEW_ICON_ACTION(w, a, i) create_action(w, &a, ICON_NAME(i), ACTION_NAME(a))
-    CREATE_NEW_ICON_ACTION(mainWindow, actionActualSize, zoom-original);
-    CREATE_NEW_ICON_ACTION(mainWindow, actionToggleMaximize, view-fullscreen);
-    CREATE_NEW_ICON_ACTION(mainWindow, actionZoomIn, zoom-in);
-    CREATE_NEW_ICON_ACTION(mainWindow, actionZoomOut, zoom-out);
-    CREATE_NEW_ICON_ACTION(mainWindow, actionToggleCheckerboard, view-background-checkerboard);
-    CREATE_NEW_ICON_ACTION(mainWindow, actionRotateClockwise, object-rotate-right);
+    /// This macro for register normal action.
+    #define CREATE_NEW_ACTION(w, a) create_action(w, &a, QString(), ACTION_NAME(a))
+    /// This macro for register Qt theme action.
+    #define CREATE_NEW_THEMEICON_ACTION(w, a, i) create_action(w, &a, QLatin1String(STRIFY(i)), ACTION_NAME(a), true)
+    /// This macro for register action with our custom icon.
+    #define CREATE_NEW_ICON_ACTION(w, a, i) create_action(w, &a, ICON_NAME(i), ACTION_NAME(a), false)
+
+    // TODO: We may replace all Qt theme icons to our custom icon for visual consistency.
+    // TODO: Some icons are invalid.
+
+    CREATE_NEW_ACTION(mainWindow, actionCopyPixmap);
+    CREATE_NEW_ACTION(mainWindow, actionCopyFilePath);
+
     CREATE_NEW_ICON_ACTION(mainWindow, actionPrevPicture, go-previous);
     CREATE_NEW_ICON_ACTION(mainWindow, actionNextPicture, go-next);
-    #undef CREATE_NEW_ICON_ACTION
 
-    #define CREATE_NEW_ACTION(w, a) create_action(w, &a, QString(), ACTION_NAME(a))
-    #define CREATE_NEW_THEMEICON_ACTION(w, a, i) create_action(w, &a, QLatin1String(STRIFY(i)), ACTION_NAME(a), true)
-    CREATE_NEW_ACTION(mainWindow, actionRotateCounterClockwise);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionActualSize, zoom-original);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionFitToScreen, app-icon);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionFitByWidth, app-icon);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionFitByHeight, app-icon);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionZoomIn, zoom-in);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionZoomOut, zoom-out);
 
+    CREATE_NEW_ICON_ACTION(mainWindow, actionFlipHorizontal, app-icon);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionFlipVertical, app-icon);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionRotateClockwise, object-rotate-right);
+    CREATE_NEW_ICON_ACTION(mainWindow, actionRotateCounterClockwise, app-icon);
+
+    CREATE_NEW_ACTION(mainWindow, actionToggleAvoidResetTransform);
+    CREATE_NEW_ACTION(mainWindow, actionToggleCheckerboard);
     CREATE_NEW_ACTION(mainWindow, actionTogglePauseAnimation);
     CREATE_NEW_ACTION(mainWindow, actionAnimationNextFrame);
 
-    CREATE_NEW_THEMEICON_ACTION(mainWindow, actionOpen, document-open);
-    CREATE_NEW_ACTION(mainWindow, actionHorizontalFlip);
-    CREATE_NEW_ACTION(mainWindow, actionFitInView);
-    CREATE_NEW_ACTION(mainWindow, actionFitByWidth);
-    CREATE_NEW_THEMEICON_ACTION(mainWindow, actionCopyPixmap, edit-copy);
-    CREATE_NEW_ACTION(mainWindow, actionCopyFilePath);
-    CREATE_NEW_THEMEICON_ACTION(mainWindow, actionPaste, edit-paste);
     CREATE_NEW_THEMEICON_ACTION(mainWindow, actionTrash, edit-delete);
-    CREATE_NEW_ACTION(mainWindow, actionToggleAvoidResetTransform);
-    CREATE_NEW_ACTION(mainWindow, actionSettings);
-    CREATE_NEW_THEMEICON_ACTION(mainWindow, actionHelp, system-help);
     CREATE_NEW_THEMEICON_ACTION(mainWindow, actionLocateInFileManager, system-file-manager);
     CREATE_NEW_THEMEICON_ACTION(mainWindow, actionProperties, document-properties);
-    CREATE_NEW_ACTION(mainWindow, actionQuitApp);
-    #undef CREATE_NEW_ACTION
+
+    CREATE_NEW_ACTION(mainWindow, actionSettings);
+    CREATE_NEW_THEMEICON_ACTION(mainWindow, actionHelp, system-help);
+
+    // Remove convenient macros
+
+    #undef CREATE_NEW_ICON_ACTION
     #undef CREATE_NEW_THEMEICON_ACTION
+    #undef CREATE_NEW_ACTION
 
     #undef STRIFY
     #undef ACTION_NAME
@@ -80,34 +97,40 @@ void ActionManager::setupAction(MainWindow *mainWindow)
 
     // endregion
 
+    // region: Setup Checkable Action
+
+    actionToggleAvoidResetTransform->setCheckable(true);
+    actionToggleCheckerboard->setCheckable(true);
+    actionTogglePauseAnimation->setCheckable(true);
+
+    // endregion
+
     // region: Action Translatable Text Setup
 
-    actionOpen->setText(QCoreApplication::translate("MainWindow", "&Open...", nullptr));
-
-    actionActualSize->setText(QCoreApplication::translate("MainWindow", "Actual size", nullptr));
-    actionToggleMaximize->setText(QCoreApplication::translate("MainWindow", "Toggle maximize", nullptr));
-    actionZoomIn->setText(QCoreApplication::translate("MainWindow", "Zoom in", nullptr));
-    actionZoomOut->setText(QCoreApplication::translate("MainWindow", "Zoom out", nullptr));
-    actionToggleCheckerboard->setText(QCoreApplication::translate("MainWindow", "Toggle Checkerboard", nullptr));
-    actionRotateClockwise->setText(QCoreApplication::translate("MainWindow", "Rotate right", nullptr));
-    actionRotateCounterClockwise->setText(QCoreApplication::translate("MainWindow", "Rotate left", nullptr));
+    actionCopyPixmap->setText(QCoreApplication::translate("MainWindow", "Copy P&ixmap", nullptr));
+    actionCopyFilePath->setText(QCoreApplication::translate("MainWindow", "Copy &File Path", nullptr));
 
     actionPrevPicture->setText(QCoreApplication::translate("MainWindow", "Previous image", nullptr));
     actionNextPicture->setText(QCoreApplication::translate("MainWindow", "Next image", nullptr));
 
+    actionActualSize->setText(QCoreApplication::translate("MainWindow", "Actual size", nullptr));
+    actionFitToScreen->setText(QCoreApplication::translate("MainWindow", "Fit to screen", nullptr));
+    actionFitByWidth->setText(QCoreApplication::translate("MainWindow", "Fit by width", nullptr));
+    actionFitByHeight->setText(QCoreApplication::translate("MainWindow", "Fit by height", nullptr));
+    actionZoomIn->setText(QCoreApplication::translate("MainWindow", "Zoom in", nullptr));
+    actionZoomOut->setText(QCoreApplication::translate("MainWindow", "Zoom out", nullptr));
+
+    actionFlipHorizontal->setText(QCoreApplication::translate("MainWindow", "Flip &Horizontally", nullptr));
+    actionFlipVertical->setText(QCoreApplication::translate("MainWindow", "Flip &Vertically", nullptr));
+    actionRotateClockwise->setText(QCoreApplication::translate("MainWindow", "Rotate right", nullptr));
+    actionRotateCounterClockwise->setText(QCoreApplication::translate("MainWindow", "Rotate left", nullptr));
+
+    actionToggleAvoidResetTransform->setText(QCoreApplication::translate("MainWindow", "Keep transformation", "The 'transformation' means the flip/rotation status that currently applied to the image view"));
+    actionToggleCheckerboard->setText(QCoreApplication::translate("MainWindow", "Toggle Checkerboard", nullptr));
     actionTogglePauseAnimation->setText(QCoreApplication::translate("MainWindow", "Pause/Resume Animation", nullptr));
     actionAnimationNextFrame->setText(QCoreApplication::translate("MainWindow", "Animation Go to Next Frame", nullptr));
 
-    actionHorizontalFlip->setText(QCoreApplication::translate("MainWindow", "Flip &Horizontally", nullptr));
-    actionFitInView->setText(QCoreApplication::translate("MainWindow", "Fit to view", nullptr));
-    actionFitByWidth->setText(QCoreApplication::translate("MainWindow", "Fit to width", nullptr));
-    actionCopyPixmap->setText(QCoreApplication::translate("MainWindow", "Copy P&ixmap", nullptr));
-    actionCopyFilePath->setText(QCoreApplication::translate("MainWindow", "Copy &File Path", nullptr));
-    actionPaste->setText(QCoreApplication::translate("MainWindow", "&Paste", nullptr));
     actionTrash->setText(QCoreApplication::translate("MainWindow", "Move to Trash", nullptr));
-    actionToggleAvoidResetTransform->setText(QCoreApplication::translate("MainWindow", "Keep transformation", "The 'transformation' means the flip/rotation status that currently applied to the image view"));
-    actionSettings->setText(QCoreApplication::translate("MainWindow", "Configure...", nullptr));
-    actionHelp->setText(QCoreApplication::translate("MainWindow", "Help", nullptr));
 #ifdef Q_OS_WIN
     actionLocateInFileManager->setText(
         QCoreApplication::translate(
@@ -119,8 +142,9 @@ void ActionManager::setupAction(MainWindow *mainWindow)
     actionLocateInFileManager->setText(QCoreApplication::translate("MainWindow", "Show in directory", nullptr));
 #endif // Q_OS_WIN
     actionProperties->setText(QCoreApplication::translate("MainWindow", "Properties", nullptr));
-    actionQuitApp->setText(QCoreApplication::translate("MainWindow", "Quit", nullptr));
 
+    actionSettings->setText(QCoreApplication::translate("MainWindow", "Configure...", nullptr));
+    actionHelp->setText(QCoreApplication::translate("MainWindow", "Help", nullptr));
     // endregion
 
     QMetaObject::connectSlotsByName(mainWindow);
@@ -128,34 +152,63 @@ void ActionManager::setupAction(MainWindow *mainWindow)
 
 void ActionManager::setupShortcuts()
 {
-    actionOpen->setShortcut(QKeySequence::Open);
+    actionCopyPixmap->setShortcut(QKeySequence::Copy);
+
+    actionPrevPicture->setShortcuts({
+        QKeySequence(Qt::Key_Left),
+        QKeySequence(Qt::Key_PageUp),
+    });
+    actionNextPicture->setShortcuts({
+        QKeySequence(Qt::Key_Right),
+        QKeySequence(Qt::Key_PageDown),
+    });
+
     actionActualSize->setShortcut(QKeySequence(Qt::CTRL | Qt::Key_0));
     actionZoomIn->setShortcut(QKeySequence::ZoomIn);
     actionZoomOut->setShortcut(QKeySequence::ZoomOut);
-    actionPrevPicture->setShortcuts({
-        QKeySequence(Qt::Key_PageUp),
-        QKeySequence(Qt::Key_Left),
-    });
-    actionNextPicture->setShortcuts({
-        QKeySequence(Qt::Key_PageDown),
-        QKeySequence(Qt::Key_Right),
-    });
-    actionHorizontalFlip->setShortcut(QKeySequence(Qt::CTRL | Qt::Key_R));
-    actionCopyPixmap->setShortcut(QKeySequence::Copy);
-    actionPaste->setShortcut(QKeySequence::Paste);
+
     actionTrash->setShortcut(QKeySequence::Delete);
-    actionHelp->setShortcut(QKeySequence::HelpContents);
-    actionSettings->setShortcut(QKeySequence::Preferences);
     actionProperties->setShortcut(QKeySequence(Qt::CTRL | Qt::Key_I));
-    actionQuitApp->setShortcuts({
-        QKeySequence(Qt::Key_Space),
-        QKeySequence(Qt::Key_Escape)
-    });
+
+    actionSettings->setShortcut(QKeySequence::Preferences);
+    actionHelp->setShortcut(QKeySequence::HelpContents);
 }
 
-void ActionManager::enablePrevNextPictureAction(bool enablePrevPictureAction, bool enableNextPictureAction)
+void ActionManager::updateActionState(PlaylistManager* pm, GraphicsView* gv)
 {
-    actionPrevPicture->setEnabled(enablePrevPictureAction);
-    actionNextPicture->setEnabled(enableNextPictureAction);
+    const auto* gs = gv->scene();
+    const auto* settings = Settings::instance();
+
+    // Update copy actions
+    bool canCopy = pm->currentIndex().has_value();
+    actionCopyPixmap->setEnabled(canCopy);
+    actionCopyFilePath->setEnabled(canCopy);
+
+    // Update Prev/Next Picture State
+    const int galleryFileCount = pm->totalCount();
+    const bool loopGallery = settings->loopGallery();
+    actionPrevPicture->setEnabled(galleryFileCount > 1 && (loopGallery || !pm->isFirstIndex()));
+    actionNextPicture->setEnabled(galleryFileCount > 1 && (loopGallery || !pm->isLastIndex()));
+
+    // Update Avoid Reset Transform
+    actionToggleAvoidResetTransform->setChecked(gv->isAvoidResetTransform());
+    // Update Checkerboard
+    actionToggleCheckerboard->setChecked(gv->isCheckerboard());
+    // Update Animation Graphics Action
+    bool canPauseAnimation = gs->canPauseAnimation();
+    actionTogglePauseAnimation->setEnabled(canPauseAnimation);
+    if (canPauseAnimation) {
+        actionTogglePauseAnimation->setChecked(gs->isPauseAnimation());
+    } else {
+        actionTogglePauseAnimation->setChecked(false);
+    }
+    bool canSkipAnimation = gs->canSkipAnimationFrame();
+    actionAnimationNextFrame->setEnabled(canSkipAnimation);
+
+    // Update trash, located in explorer and properties.
+    bool hasLoadedFile = pm->currentIndex().has_value();
+    actionTrash->setEnabled(hasLoadedFile);
+    actionLocateInFileManager->setEnabled(hasLoadedFile);
+    actionProperties->setEnabled(hasLoadedFile);
 }
 

app/actionmanager.h

@@ -8,6 +8,8 @@
 #include <QAction>
 
 class MainWindow;
+class PlaylistManager;
+class GraphicsView;
 
 /// Action Manager is separated from Main Window
 /// to manage all actions specifically.
@@ -19,38 +21,40 @@ public:
 
     void setupAction(MainWindow * mainWindow);
     void setupShortcuts();
-    void enablePrevNextPictureAction(bool enablePrevPictureAction, bool enableNextPictureAction);
+
+public slots:
+    void updateActionState(PlaylistManager* pm, GraphicsView* gv);
 
 public:
-    QAction *actionOpen;
-
-    QAction *actionActualSize;
-    QAction *actionToggleMaximize;
-    QAction *actionZoomIn;
-    QAction *actionZoomOut;
-    QAction *actionToggleCheckerboard;
-    QAction *actionRotateClockwise;
-    QAction *actionRotateCounterClockwise;
+    QAction *actionCopyPixmap;
+    QAction *actionCopyFilePath;
 
     QAction *actionPrevPicture;
     QAction *actionNextPicture;
 
+    QAction *actionActualSize;
+    QAction *actionFitToScreen;
+    QAction *actionFitByWidth;
+    QAction *actionFitByHeight;
+    QAction *actionZoomIn;
+    QAction *actionZoomOut;
+
+    QAction *actionFlipHorizontal;
+    QAction *actionFlipVertical;
+    QAction *actionRotateClockwise;
+    QAction *actionRotateCounterClockwise;
+
+    QAction *actionToggleAvoidResetTransform;
+    QAction *actionToggleCheckerboard;
     QAction *actionTogglePauseAnimation;
     QAction *actionAnimationNextFrame;
 
-    QAction *actionHorizontalFlip;
-    QAction *actionFitInView;
-    QAction *actionFitByWidth;
-    QAction *actionCopyPixmap;
-    QAction *actionCopyFilePath;
-    QAction *actionPaste;
     QAction *actionTrash;
-    QAction *actionToggleAvoidResetTransform;
-    QAction *actionSettings;
-    QAction *actionHelp;
     QAction *actionLocateInFileManager;
     QAction *actionProperties;
-    QAction *actionQuitApp;
+
+    QAction *actionSettings;
+    QAction *actionHelp;
 };
 
 #endif // ACTIONMANAGER_H

app/bottombuttongroup.cpp

@@ -8,42 +8,38 @@
 #include <QVBoxLayout>
 #include <QDebug>
 
-BottomButtonGroup::BottomButtonGroup(const std::vector<QAction *> &actionList, QWidget *parent)
+BottomButtonGroup::BottomButtonGroup(QWidget *parent)
     : QGroupBox (parent)
 {
     QHBoxLayout * mainLayout = new QHBoxLayout(this);
     mainLayout->setSizeConstraint(QLayout::SetFixedSize);
     this->setLayout(mainLayout);
     this->setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);
-    this->setStyleSheet("BottomButtonGroup {"
-                        "border: 1px solid gray;"
-                        "border-top-left-radius: 10px;"
-                        "border-top-right-radius: 10px;"
-                        "border-style: none;"
-                        "background-color:rgba(0,0,0,120)"
-                        "}"
-                        "QToolButton {"
-                        "background:transparent;"
-                        "}"
-                        "QToolButton:!focus {"
-                        "border-style: none;"
-                        "}");
+    this->setStyleSheet(R"#(
+BottomButtonGroup {
+    border-style: none;
+    background: transparent;
+}
+QToolButton {
+    background: transparent;
+    border-style: none;
+}
+)#");
+}
 
-    auto newActionBtn = [this](QAction * action) -> QToolButton * {
+void BottomButtonGroup::addActions(const std::vector<QAction *> & actionList) {
+    for (QAction * action : actionList) {
+        // Create button
         QToolButton * btn = new QToolButton(this);
         btn->setDefaultAction(action);
         btn->setIconSize(QSize(32, 32));
         btn->setFixedSize(40, 40);
-        return btn;
-    };
-
-    for (QAction * action : actionList) {
-        addButton(newActionBtn(action));
+        // Add button
+        layout()->addWidget(btn);
     }
-}
-
-void BottomButtonGroup::addButton(QAbstractButton *button)
-{
-    layout()->addWidget(button);
     updateGeometry();
 }
+
+void BottomButtonGroup::addAction(QAction* action) {
+    addActions({action});
+}

app/bottombuttongroup.h

@@ -14,9 +14,10 @@ class BottomButtonGroup : public QGroupBox
 {
     Q_OBJECT
 public:
-    explicit BottomButtonGroup(const std::vector<QAction *> & actionList, QWidget *parent = nullptr);
+    explicit BottomButtonGroup(QWidget *parent = nullptr);
 
-    void addButton(QAbstractButton *button);
+    void addActions(const std::vector<QAction *> & actionList);
+    void addAction(QAction* action);
 };
 
 #endif // BOTTOMBUTTONGROUP_H

app/framelesswindow.cpp

@@ -1,36 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Gary Wang <wzc782970009@gmail.com>
-// SPDX-FileCopyrightText: 2023 Tad Young <yyc12321@outlook.com>
-//
-// SPDX-License-Identifier: MIT
-
-#include "framelesswindow.h"
-
-#include <QMouseEvent>
-#include <QHoverEvent>
-#include <QApplication>
-#include <QVBoxLayout>
-#include <QWindow>
-
-FramelessWindow::FramelessWindow(QWidget *parent)
-    : QWidget(parent)
-    , m_centralLayout(new QVBoxLayout(this))
-{
-    this->setWindowFlags(Qt::Window | Qt::WindowTitleHint | Qt::WindowSystemMenuHint | Qt::WindowMinMaxButtonsHint | Qt::WindowCloseButtonHint);
-
-    // YYC MARK:
-    // 72 px is the height of Windows Photo Viewer's bottom line.
-
-    // TODO: This value may be declared as a constant.
-    m_centralLayout->setContentsMargins(QMargins(0, 0, 0, 72));
-}
-
-void FramelessWindow::setCentralWidget(QWidget *widget)
-{
-    if (m_centralWidget) {
-        m_centralLayout->removeWidget(m_centralWidget);
-        m_centralWidget->deleteLater();
-    }
-
-    m_centralLayout->addWidget(widget);
-    m_centralWidget = widget;
-}

app/framelesswindow.h

@@ -1,27 +0,0 @@
-// SPDX-FileCopyrightText: 2022 Gary Wang <wzc782970009@gmail.com>
-//
-// SPDX-License-Identifier: MIT
-
-#ifndef FRAMELESSWINDOW_H
-#define FRAMELESSWINDOW_H
-
-#include <QWidget>
-
-QT_BEGIN_NAMESPACE
-class QVBoxLayout;
-QT_END_NAMESPACE
-
-class FramelessWindow : public QWidget
-{
-    Q_OBJECT
-public:
-    explicit FramelessWindow(QWidget *parent = nullptr);
-
-    void setCentralWidget(QWidget * widget);
-
-private:
-    QVBoxLayout * m_centralLayout = nullptr;
-    QWidget * m_centralWidget = nullptr; // just a pointer, doesn't take the ownership.
-};
-
-#endif // FRAMELESSWINDOW_H

app/graphicsscene.cpp

@@ -6,6 +6,9 @@
 
 #include "settings.h"
 
+#include <QStyleHints>
+#include <QOperatingSystemVersion>
+#include <QGuiApplication>
 #include <QGraphicsSceneMouseEvent>
 #include <QMimeData>
 #include <QDebug>
@@ -16,6 +19,33 @@
 #include <QMovie>
 #include <QPainter>
 
+static const QColor& ColorSchemaToTextForeground(Qt::ColorScheme colorScheme) {
+    // YYC MARK:
+    // If we are using Windows 10 and lower system or Qt which do not support "Windows 11"
+    // theme (lower than Qt 6.7), we should only support light mode.
+    // Because Qt's dark-mode-aware "Windows 11" theme is only well-supported on Windows 11.
+#if defined(Q_OS_WIN)
+#if QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
+    colorScheme = Qt::ColorScheme::Light;
+#else
+    if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows11) {
+        colorScheme = Qt::ColorScheme::Light;
+    }
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
+#endif // defined(Q_OS_WIN)
+
+    switch (colorScheme) {
+    case Qt::ColorScheme::Dark:
+        static QColor WHITE = QColor("White");
+        return WHITE;
+    case Qt::ColorScheme::Light:
+    case Qt::ColorScheme::Unknown:
+    default:
+        static QColor BLACK = QColor("Black");
+        return BLACK;
+    }
+}
+
 class PGraphicsPixmapItem : public QGraphicsPixmapItem
 {
 public:
@@ -99,7 +129,8 @@ private:
 GraphicsScene::GraphicsScene(QObject *parent)
     : QGraphicsScene(parent)
 {
-    showText(tr("Drag image here"));
+    showText(tr("Drag image here", "The same meaning of MainWindow's hint."));
+    connect(qGuiApp->styleHints(), &QStyleHints::colorSchemeChanged, this, &GraphicsScene::updateStyle);
 }
 
 GraphicsScene::~GraphicsScene()
@@ -121,7 +152,7 @@ void GraphicsScene::showText(const QString &text)
 {
     this->clear();
     QGraphicsTextItem * textItem = this->addText(text);
-    textItem->setDefaultTextColor(QColor("White"));
+    textItem->setDefaultTextColor(ColorSchemaToTextForeground(qGuiApp->styleHints()->colorScheme()));
     m_theThing = textItem;
     this->setSceneRect(m_theThing->boundingRect());
 }
@@ -169,28 +200,58 @@ bool GraphicsScene::trySetTransformationMode(Qt::TransformationMode mode, float
     return false;
 }
 
+/// Fetch graphics item as our custom animated item.
+/// Return nullptr means this item is not animated item.
+static PGraphicsMovieItem* fetchAnimatedItem(QGraphicsItem *item) {
+    return qgraphicsitem_cast<PGraphicsMovieItem *>(item);
+}
+
+bool GraphicsScene::canPauseAnimation() const {
+    return fetchAnimatedItem(m_theThing) != nullptr;
+}
+
+bool GraphicsScene::isPauseAnimation() const {
+    auto* animatedItem = fetchAnimatedItem(m_theThing);
+    if (animatedItem != nullptr) {
+        return animatedItem->movie()->state() == QMovie::Paused;
+    } else {
+        return false;
+    }
+}
+
 bool GraphicsScene::togglePauseAnimation()
 {
-    PGraphicsMovieItem * animatedItem = qgraphicsitem_cast<PGraphicsMovieItem *>(m_theThing);
-    if (animatedItem) {
+    auto* animatedItem = fetchAnimatedItem(m_theThing);
+    if (animatedItem != nullptr) {
         animatedItem->movie()->setPaused(animatedItem->movie()->state() != QMovie::Paused);
         return true;
-    }
+    } else {
         return false;
     }
+}
+
+bool GraphicsScene::canSkipAnimationFrame() const {
+    return isPauseAnimation();
+}
 
 bool GraphicsScene::skipAnimationFrame(int delta)
 {
-    PGraphicsMovieItem * animatedItem = qgraphicsitem_cast<PGraphicsMovieItem *>(m_theThing);
-    if (animatedItem) {
+    auto* animatedItem = fetchAnimatedItem(m_theThing);
+
+    // Only paused animated item can skip frame
+    if (animatedItem == nullptr) {
+        return false;
+    }
+    if (animatedItem->movie()->state() != QMovie::Paused) {
+        return false;
+    }
+
+    // Perform skip
     const int frameCount = animatedItem->movie()->frameCount();
     const int currentFrame = animatedItem->movie()->currentFrameNumber();
     const int targetFrame = (currentFrame + delta) % frameCount;
-        animatedItem->movie()->setPaused(true);
     return animatedItem->movie()->jumpToFrame(targetFrame);
 }
-    return false;
-}
 
 QPixmap GraphicsScene::renderToPixmap()
 {
@@ -206,3 +267,14 @@ QPixmap GraphicsScene::renderToPixmap()
 
     return pixmap;
 }
+
+void GraphicsScene::updateStyle(Qt::ColorScheme colorScheme) {
+    Q_UNUSED(colorScheme)
+
+    QGraphicsItem * item = this->m_theThing;
+    if (item == nullptr) return;
+    QGraphicsTextItem * textItem = qgraphicsitem_cast<QGraphicsTextItem*>(item);
+    if (textItem == nullptr) return;
+
+    textItem->setDefaultTextColor(ColorSchemaToTextForeground(colorScheme));
+}

app/graphicsscene.h

@@ -21,11 +21,26 @@ public:
 
     bool trySetTransformationMode(Qt::TransformationMode mode, float scaleHint);
 
+    /// Check whether current thing is animation.
+    /// Only animation thing can be paused.
+    bool canPauseAnimation() const;
+    /// Check whether we are pasuing an animation graphics.
+    bool isPauseAnimation() const;
+    /// Toggle animation graphics pause state.
+    /// Return true for successfully toggle, otherwise false.
     bool togglePauseAnimation();
+    /// Check whether we can skip animation frame.
+    /// Only paused animation graphics can skip frame.
+    bool canSkipAnimationFrame() const;
+    /// Skip paused animation graphics with given frame.
+    /// Return true for successfully skip, otherwise false.
     bool skipAnimationFrame(int delta = 1);
 
     QPixmap renderToPixmap();
 
+private slots:
+    void updateStyle(Qt::ColorScheme colorScheme);
+
 private:
     QGraphicsItem * m_theThing = nullptr;
 };

app/graphicsview.cpp

@@ -7,6 +7,8 @@
 #include "graphicsscene.h"
 #include "settings.h"
 
+#include <QStyleHints>
+#include <QOperatingSystemVersion>
 #include <QDebug>
 #include <QColorSpace>
 #include <QMouseEvent>
@@ -23,11 +25,12 @@ GraphicsView::GraphicsView(QWidget *parent)
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setResizeAnchor(QGraphicsView::AnchorUnderMouse);
     setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
-    setStyleSheet("background-color: rgba(0, 0, 0, 220);"
-                  "border-radius: 3px;");
     setAcceptDrops(false);
     setCheckerboardEnabled(false);
 
+    updateStyle(qGuiApp->styleHints()->colorScheme());
+    connect(qGuiApp->styleHints(), &QStyleHints::colorSchemeChanged, this, &GraphicsView::updateStyle);
+
     connect(horizontalScrollBar(), &QScrollBar::valueChanged, this, &GraphicsView::viewportRectChanged);
     connect(verticalScrollBar(), &QScrollBar::valueChanged, this, &GraphicsView::viewportRectChanged);
 }
@@ -137,7 +140,7 @@ void GraphicsView::resetTransform()
 
 void GraphicsView::zoomView(qreal scaleFactor)
 {
-    m_enableFitInView = false;
+    m_enableFitToScreen = false;
     scale(scaleFactor, scaleFactor);
     applyTransformationModeByScaleFactor();
     emit navigatorViewRequired(!isThingSmallerThanWindowWith(transform()), transform());
@@ -221,6 +224,19 @@ void GraphicsView::fitByOrientation(Qt::Orientation ori, bool scaleDownOnly)
     QRectF originalScene = sceneRect();
     QTransform currentTransform = transform();
     
+    // TODO: 
+    // I guess following code may be optimized by matrix arithmetic operation.
+    // There is an AI given solution. But I didn't use it.
+    // Because I want to keep the same behavior of upstream.
+
+    // // Horizontal fit: Let the position of top center of viewport, (cx, 0), be inversely mapped to scene.
+    // // And compensate the behavior of `centerOn` which put given point to the center of viewport.
+    // QTransform inv = currentTransform.inverted();
+    // QPointF viewCx = viewport()->rect().center().x();
+    // QPointF viewCy = viewport()->rect().center().y();
+    // // The target is viewport top center. Its y=0, so `centerOn` required scene point is (viewCx, -viewCy).
+    // centerOn(inv.map(QPointF(viewCx, -viewCy)));
+
     if (ori == Qt::Horizontal) {
         // For horizontal fit (fit by width), position at top (for tall images)
         // Find the scene point that corresponds to the top-center of the transformed image
@@ -273,7 +289,7 @@ void GraphicsView::fitByOrientation(Qt::Orientation ori, bool scaleDownOnly)
         centerOn(sceneLeftCenter);
     }
 
-    m_enableFitInView = false;
+    m_enableFitToScreen = false;
 
     applyTransformationModeByScaleFactor();
     emit navigatorViewRequired(!isThingSmallerThanWindowWith(transform()), transform());
@@ -296,7 +312,7 @@ void GraphicsView::displayScene()
         emit navigatorViewRequired(false, transform());
     }
 
-    m_enableFitInView = true;
+    m_enableFitToScreen = true;
     m_firstUserMediaLoaded = true;
 }
 
@@ -310,12 +326,12 @@ bool GraphicsView::isSceneBiggerThanView() const
 }
 
 // Automately do fit in view when viewport(window) smaller than image original size.
-void GraphicsView::setEnableAutoFitInView(bool enable)
+void GraphicsView::setEnableAutoFitToScreen(bool enable)
 {
-    m_enableFitInView = enable;
+    m_enableFitToScreen = enable;
 }
 
-bool GraphicsView::avoidResetTransform() const
+bool GraphicsView::isAvoidResetTransform() const
 {
     return m_avoidResetTransform;
 }
@@ -325,6 +341,15 @@ void GraphicsView::setAvoidResetTransform(bool avoidReset)
     m_avoidResetTransform = avoidReset;
 }
 
+bool GraphicsView::isCheckerboard() const {
+    return m_checkerboardEnabled;
+}
+
+void GraphicsView::toggleCheckerboard(bool invertCheckerboardColor)
+{
+    setCheckerboardEnabled(!m_checkerboardEnabled, invertCheckerboardColor);
+}
+
 inline double zeroOrOne(double number)
 {
     return qFuzzyIsNull(number) ? 0 : (number > 0 ? 1 : -1);
@@ -339,9 +364,37 @@ QTransform GraphicsView::resetScale(const QTransform & orig)
                       orig.dx(),             orig.dy());
 }
 
-void GraphicsView::toggleCheckerboard(bool invertCheckerboardColor)
-{
-    setCheckerboardEnabled(!m_checkerboardEnabled, invertCheckerboardColor);
+void GraphicsView::updateStyle(Qt::ColorScheme colorScheme) {
+    // YYC MARK:
+    // If we are using Windows 10 and lower system or Qt which do not support "Windows 11"
+    // theme (lower than Qt 6.7), we should only support light mode.
+    // Because Qt's dark-mode-aware "Windows 11" theme is only well-supported on Windows 11.
+#if defined(Q_OS_WIN)
+#if QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
+    colorScheme = Qt::ColorScheme::Light;
+#else
+    if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows11) {
+        colorScheme = Qt::ColorScheme::Light;
+    }
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
+#endif // defined(Q_OS_WIN)
+
+    switch (colorScheme) {
+    case Qt::ColorScheme::Dark:
+        setStyleSheet(R"#(
+border-style: none;
+background-color: black;
+)#");
+        break;
+    case Qt::ColorScheme::Light:
+    case Qt::ColorScheme::Unknown:
+    default:
+        setStyleSheet(R"#(
+border-style: none;
+background-color: white;
+)#");
+        break;
+    }
 }
 
 void GraphicsView::mousePressEvent(QMouseEvent *event)
@@ -387,11 +440,11 @@ void GraphicsView::wheelEvent(QWheelEvent *event)
 
 void GraphicsView::resizeEvent(QResizeEvent *event)
 {
-    if (m_enableFitInView) {
+    if (m_enableFitToScreen) {
         bool originalSizeSmallerThanWindow = isThingSmallerThanWindowWith(resetScale(transform()));
         if (originalSizeSmallerThanWindow && scaleFactor() >= 1) {
             // no longer need to do fitInView()
-            // but we leave the m_enableFitInView value unchanged in case
+            // but we leave the m_enableToScreen value unchanged in case
             // user resize down the window again.
         } else if (originalSizeSmallerThanWindow && scaleFactor() < 1) {
             resetScale();

app/graphicsview.h

@@ -38,19 +38,22 @@ public:
 
     void displayScene();
     bool isSceneBiggerThanView() const;
-    void setEnableAutoFitInView(bool enable = true);
+    void setEnableAutoFitToScreen(bool enable = true);
 
-    bool avoidResetTransform() const;
+    bool isAvoidResetTransform() const;
     void setAvoidResetTransform(bool avoidReset);
 
+    bool isCheckerboard() const;
+    void toggleCheckerboard(bool invertCheckerboardColor = false);
+
     static QTransform resetScale(const QTransform & orig);
 
 signals:
     void navigatorViewRequired(bool required, QTransform transform);
     void viewportRectChanged();
 
-public slots:
-    void toggleCheckerboard(bool invertCheckerboardColor = false);
+private slots:
+    void updateStyle(Qt::ColorScheme colorScheme);
 
 private:
     void mousePressEvent(QMouseEvent * event) override;
@@ -69,7 +72,7 @@ private:
     // Consider switch to 3 state for "no fit", "always fit" and "fit when view is smaller"?
     // ... or even more? e.g. "fit/snap width" things...
     // Currently it's "no fit" when it's false and "fit when view is smaller" when it's true.
-    bool m_enableFitInView = false;
+    bool m_enableFitToScreen = false;
     bool m_avoidResetTransform = false;
     bool m_checkerboardEnabled = false;
     bool m_useLightCheckerboard = false;

app/main.cpp

@@ -4,7 +4,6 @@
 
 #include "mainwindow.h"
 
-#include "playlistmanager.h"
 #include "settings.h"
 
 #ifdef Q_OS_MACOS
@@ -68,21 +67,19 @@ int main(int argc, char *argv[])
     a.installEventFilter(fileOpenEventHandler);
     a.connect(fileOpenEventHandler, &FileOpenEventHandler::fileOpen, [&w](const QUrl & url){
         if (w.isHidden()) {
-            w.setWindowOpacity(1);
             w.showNormal();
         } else {
             w.activateWindow();
         }
-        w.showUrls({url});
+        w.showFiles({url});
         w.initWindowSize();
     });
 
     // Handle dock icon clicks to show hidden window
     a.connect(&a, &QApplication::applicationStateChanged, [&w](Qt::ApplicationState state) {
         if (state == Qt::ApplicationActive && w.isHidden()) {
-            w.showUrls({});
-            w.galleryCurrent(true, true);
-            w.setWindowOpacity(1);
+            w.showFiles({});
+            w.galleryCurrent(false);
             w.showNormal();
             w.raise();
             w.activateWindow();
@@ -90,12 +87,8 @@ int main(int argc, char *argv[])
     });
 #endif // Q_OS_MACOS
 
-    QStringList urlStrList = parser.positionalArguments();
-    QList<QUrl> && urlList = PlaylistManager::convertToUrlList(urlStrList);
-
-    if (!urlList.isEmpty()) {
-        w.showUrls(urlList);
-    }
+    QStringList fileList = parser.positionalArguments();
+    w.showFiles(fileList);
 
     w.initWindowSize();
 

app/mainwindow.cpp

@@ -3,6 +3,7 @@
 // SPDX-License-Identifier: MIT
 
 #include "mainwindow.h"
+#include "ui_mainwindow.h"
 
 #include "settings.h"
 #include "bottombuttongroup.h"
@@ -46,76 +47,124 @@
 using namespace Qt::Literals::StringLiterals;
 
 MainWindow::MainWindow(QWidget *parent)
-    : FramelessWindow(parent)
+    : QWidget(parent)
+    , ui(new QT_PREPEND_NAMESPACE(Ui::MainWindow))
     , m_am(new ActionManager)
     , m_pm(new PlaylistManager(this))
     , m_fileSystemWatcher(new QFileSystemWatcher(this))
 {
-    this->setAttribute(Qt::WA_TranslucentBackground, true);
+    ui->setupUi(this);
+    this->setWindowFlags(Qt::Window | Qt::WindowTitleHint | Qt::WindowSystemMenuHint | Qt::WindowMinMaxButtonsHint | Qt::WindowCloseButtonHint);
+
     // YYC MARK:
     // Blumis set original value is 350 x 330.
     // It is too small for modern device,
-    // so I level it up to standard VGA resolution 640 x 480.
-    this->setMinimumSize(640, 480);
+    // so I level it up to SVGA resolution 800 x 600.
+    this->setMinimumSize(800, 600);
     this->setWindowIcon(QIcon(u":/icons/app-icon.svg"_s));
-    this->setMouseTracking(true);
     this->setAcceptDrops(true);
 
-    m_pm->setAutoLoadFilterSuffixes(supportedImageFormats());
+    // Initialize playlist manager
+    m_pm->setAllowedSuffixes(supportedImageFormats());
 
+    // Initialize graphics scene
     GraphicsScene * scene = new GraphicsScene(this);
-
-    m_gv = new GraphicsView(this);
-    m_gv->setScene(scene);
-    this->setCentralWidget(m_gv);
-
-    m_nav = new NavigatorView(this);
-    // YYC MARK:
-    // Blumia set original value is 220 x 160.
-    // So if we set its height to 72 for respecting the height of Windows Photo Viewer,
-    // the width should be set to 99 for keeping aspect ratio.
-    m_nav->setFixedSize(99, 72);
-    m_nav->setScene(scene);
-    m_nav->setMainView(m_gv);
-    m_nav->fitInView(m_nav->sceneRect(), Qt::KeepAspectRatio);
-
-    connect(m_gv, &GraphicsView::navigatorViewRequired,
+    // Setup graphics view (main photo view)
+    ui->m_gv->setScene(scene);
+    // Setup navigator view (right-bottom corner thumbnail view)
+    ui->m_nav->setScene(scene);
+    ui->m_nav->setMainView(ui->m_gv);
+    ui->m_nav->fitInView(ui->m_nav->sceneRect(), Qt::KeepAspectRatio);
+    // Binding graphics and navigator views signals
+    connect(ui->m_gv, &GraphicsView::navigatorViewRequired,
             this, [this](bool required, const QTransform & tf){
-        m_nav->setTransform(GraphicsView::resetScale(tf));
-        m_nav->fitInView(m_nav->sceneRect(), Qt::KeepAspectRatio);
-        m_nav->setVisible(required);
-        m_nav->updateMainViewportRegion();
+        ui->m_nav->setTransform(GraphicsView::resetScale(tf));
+        ui->m_nav->fitInView(ui->m_nav->sceneRect(), Qt::KeepAspectRatio);
+        ui->m_nav->setVisible(required);
+        ui->m_navPH->setVisible(required);
+        ui->m_nav->updateMainViewportRegion();
     });
+    connect(ui->m_gv, &GraphicsView::viewportRectChanged,
+            ui->m_nav, &NavigatorView::updateMainViewportRegion);
 
-    connect(m_gv, &GraphicsView::viewportRectChanged,
-            m_nav, &NavigatorView::updateMainViewportRegion);
-
+    // Setup action manager
     m_am->setupAction(this);
-
-    m_bottomButtonGroup = new BottomButtonGroup({
+    // Setup bottom button group
+    ui->m_bottomButtonGroup->addActions({
         m_am->actionActualSize,
-        m_am->actionToggleMaximize,
+        m_am->actionFitToScreen,
         m_am->actionZoomIn,
         m_am->actionZoomOut,
         m_am->actionPrevPicture,
+        m_am->actionProperties,
         m_am->actionNextPicture,
-        m_am->actionToggleCheckerboard,
-        m_am->actionRotateClockwise
-    }, this);
+        m_am->actionRotateCounterClockwise,
+        m_am->actionRotateClockwise,
+        m_am->actionFlipHorizontal,
+        m_am->actionFlipVertical,
+    });
+    // Setup right click menus
+    {
+        ui->m_subMenuCopy->addAction(m_am->actionCopyPixmap);
+        ui->m_subMenuCopy->addAction(m_am->actionCopyFilePath);
+    }
+    {
+        ui->m_subMenuTransform->addAction(m_am->actionActualSize);
+        ui->m_subMenuTransform->addAction(m_am->actionFitToScreen);
+        ui->m_subMenuTransform->addAction(m_am->actionFitByWidth);
+        ui->m_subMenuTransform->addAction(m_am->actionFitByHeight);
+        ui->m_subMenuTransform->addAction(m_am->actionZoomIn);
+        ui->m_subMenuTransform->addAction(m_am->actionZoomOut);
 
-    connect(m_pm, &PlaylistManager::totalCountChanged, this, &MainWindow::updateGalleryButtonsVisibility);
+        ui->m_subMenuTransform->addSeparator();
 
-    connect(m_pm->model(), &PlaylistModel::modelReset, this, std::bind(&MainWindow::galleryCurrent, this, false, false));
-    connect(m_pm, &PlaylistManager::currentIndexChanged, this, std::bind(&MainWindow::galleryCurrent, this, true, false));
+        ui->m_subMenuTransform->addAction(m_am->actionFlipHorizontal);
+        ui->m_subMenuTransform->addAction(m_am->actionFlipVertical);
+        ui->m_subMenuTransform->addAction(m_am->actionRotateClockwise);
+        ui->m_subMenuTransform->addAction(m_am->actionRotateCounterClockwise);
+    }
+    {
+        ui->m_menu->addMenu(ui->m_subMenuCopy);
+
+        ui->m_menu->addSeparator();
+
+        ui->m_menu->addAction(m_am->actionPrevPicture);
+        ui->m_menu->addAction(m_am->actionNextPicture);
+
+        ui->m_menu->addSeparator();
+
+        ui->m_menu->addMenu(ui->m_subMenuTransform);
+
+        ui->m_menu->addSeparator();
+
+        ui->m_menu->addAction(m_am->actionToggleAvoidResetTransform);
+        ui->m_menu->addAction(m_am->actionToggleCheckerboard);
+        ui->m_menu->addAction(m_am->actionTogglePauseAnimation);
+        ui->m_menu->addAction(m_am->actionAnimationNextFrame);
+
+        ui->m_menu->addSeparator();
+
+        ui->m_menu->addAction(m_am->actionTrash);
+        ui->m_menu->addAction(m_am->actionLocateInFileManager);
+        ui->m_menu->addAction(m_am->actionProperties);
+
+        ui->m_menu->addSeparator();
+
+        ui->m_menu->addAction(m_am->actionSettings);
+        ui->m_menu->addAction(m_am->actionHelp);
+    }
+
+    // Connect playlist manager and file watcher signals for photo browsering.
+    connect(m_pm, &PlaylistManager::playlistChanged, this, std::bind(&MainWindow::updateActionState, this));
+
+    connect(m_pm, &PlaylistManager::playlistChanged, this, std::bind(&MainWindow::galleryCurrent, this, false));
+    connect(m_pm, &PlaylistManager::currentIndexChanged, this, std::bind(&MainWindow::galleryCurrent, this, false));
 
     connect(m_fileSystemWatcher, &QFileSystemWatcher::fileChanged, this, [this](){
-        QTimer::singleShot(500, this, std::bind(&MainWindow::galleryCurrent, this, false, true));
+        QTimer::singleShot(500, this, std::bind(&MainWindow::galleryCurrent, this, true));
     });
 
-    QShortcut * fullscreenShorucut = new QShortcut(QKeySequence(QKeySequence::FullScreen), this);
-    connect(fullscreenShorucut, &QShortcut::activated,
-            this, &MainWindow::toggleFullscreen);
-
+    // Change window location
     centerWindow();
 
     QTimer::singleShot(0, this, [this](){
@@ -126,89 +175,37 @@ MainWindow::MainWindow(QWidget *parent)
 
 MainWindow::~MainWindow()
 {
-
+    delete ui;
 }
 
-void MainWindow::showUrls(const QList<QUrl> &urls)
+void MainWindow::showFiles(const QStringList &files)
 {
-    if (!urls.isEmpty()) {
-        const QUrl & firstUrl = urls.first();
-        if (urls.count() == 1) {
-            const QString lowerCaseUrlPath(firstUrl.path().toLower());
-            if (lowerCaseUrlPath.endsWith(".m3u8") || lowerCaseUrlPath.endsWith(".m3u")) {
-                m_pm->loadM3U8Playlist(firstUrl);
-                galleryCurrent(true, true);
-                return;
-            }
-        }
-        m_gv->showFileFromPath(firstUrl.toLocalFile());
-        m_pm->loadPlaylist(urls);
-    } else {
-        m_gv->showText(tr("File url list is empty"));
-        m_pm->setPlaylist(urls);
-        return;
+    m_pm->loadPlaylist(files);
+    ui->m_nav->fitInView(ui->m_nav->sceneRect(), Qt::KeepAspectRatio);
 }
 
-    m_nav->fitInView(m_nav->sceneRect(), Qt::KeepAspectRatio);
+void MainWindow::showFiles(const QList<QUrl>& urls)
+{
+    m_pm->loadPlaylist(urls);
+    ui->m_nav->fitInView(ui->m_nav->sceneRect(), Qt::KeepAspectRatio);
 }
 
 void MainWindow::initWindowSize()
 {
     switch (Settings::instance()->initWindowSizeBehavior()) {
-    case Settings::WindowSizeBehavior::Auto:
-        adjustWindowSizeBySceneRect();
-        break;
     case Settings::WindowSizeBehavior::Maximized:
         showMaximized();
         break;
     case Settings::WindowSizeBehavior::Windowed:
+    default:
         showNormal();
         break;
-    default:
-        adjustWindowSizeBySceneRect();
-        break;
     }
 }
 
-void MainWindow::adjustWindowSizeBySceneRect()
-{
-    if (m_pm->totalCount() < 1) return;
-
-    QSize sceneSize = m_gv->sceneRect().toRect().size();
-    QSize sceneSizeWithMargins = sceneSize + QSize(130, 125);
-
-    if (m_gv->scaleFactor() < 1 || size().expandedTo(sceneSizeWithMargins) != size()) {
-        // if it scaled down by the resize policy:
-        QSize screenSize = qApp->screenAt(QCursor::pos())->availableSize();
-        if (screenSize.expandedTo(sceneSize) == screenSize) {
-            // we can show the picture by increase the window size.
-            QSize finalSize = (screenSize.expandedTo(sceneSizeWithMargins) == screenSize) ?
-                              sceneSizeWithMargins : screenSize;
-            // We have a very reasonable sizeHint() value ;P
-            this->resize(finalSize.expandedTo(this->sizeHint()));
-
-            // We're sure the window can display the whole thing with 1:1 scale.
-            // The old window size may cause fitInView call from resize() and the
-            // above resize() call won't reset the scale back to 1:1, so we
-            // just call resetScale() here to ensure the thing is no longer scaled.
-            m_gv->resetScale();
-            centerWindow();
-        } else {
-            // toggle maximum
-            showMaximized();
-        }
-    }
-}
-
-// can be empty if it is NOT from a local file.
-QUrl MainWindow::currentImageFileUrl() const
-{
-    return m_pm->urlByIndex(m_pm->curIndex());
-}
-
 void MainWindow::clearGallery()
 {
-    m_pm->setPlaylist({});
+    m_pm->clearPlaylist();
 }
 
 void MainWindow::galleryPrev()
@@ -216,10 +213,9 @@ void MainWindow::galleryPrev()
     const bool loopGallery = Settings::instance()->loopGallery();
     if (!loopGallery && m_pm->isFirstIndex()) return;
 
-    QModelIndex index = m_pm->previousIndex();
-    if (index.isValid()) {
-        m_pm->setCurrentIndex(index);
-        m_gv->showFileFromPath(m_pm->localFileByIndex(index));
+    auto index = m_pm->previousIndex();
+    if (index.has_value()) {
+        m_pm->setCurrentIndex(*index);
     }
 }
 
@@ -228,31 +224,29 @@ void MainWindow::galleryNext()
     const bool loopGallery = Settings::instance()->loopGallery();
     if (!loopGallery && m_pm->isLastIndex()) return;
 
-    QModelIndex index = m_pm->nextIndex();
-    if (index.isValid()) {
-        m_pm->setCurrentIndex(index);
-        m_gv->showFileFromPath(m_pm->localFileByIndex(index));
+    auto index = m_pm->nextIndex();
+    if (index.has_value()) {
+        m_pm->setCurrentIndex(*index);
     }
 }
 
-// Only use this to update minor information.
-void MainWindow::galleryCurrent(bool showLoadImageHintWhenEmpty, bool reloadImage)
+void MainWindow::galleryCurrent(bool fromFileWatcher)
 {
-    QModelIndex index = m_pm->curIndex();
-    bool shouldResetfileWatcher = true;
-    if (index.isValid()) {
-        const QString & localFilePath(m_pm->localFileByIndex(index));
-        if (reloadImage) m_gv->showFileFromPath(localFilePath);
-        shouldResetfileWatcher = !updateFileWatcher(localFilePath);
-        setWindowTitle(m_pm->urlByIndex(index).fileName());
-    } else if (showLoadImageHintWhenEmpty && m_pm->totalCount() <= 0) {
-        m_gv->showText(QCoreApplication::translate("GraphicsScene", "Drag image here"));
+    auto index = m_pm->currentIndex();
+    if (index.has_value()) {
+        QString localFilePath = m_pm->localFileByIndex(*index);
+        ui->m_gv->showFileFromPath(localFilePath);
+        if (!fromFileWatcher) {
+            updateFileWatcher(localFilePath);
+            setWindowTitle(m_pm->urlByIndex(*index).fileName());
+        }
+    } else {
+        ui->m_gv->showText(tr("Drag image here"));
         setWindowTitle(QString());
+        updateFileWatcher();
     }
 
-    updateGalleryButtonsVisibility();
-
-    if (shouldResetfileWatcher) updateFileWatcher();
+    updateActionState();
 }
 
 QStringList MainWindow::supportedImageFormats()
@@ -268,53 +262,6 @@ QStringList MainWindow::supportedImageFormats()
     return formatFilters;
 }
 
-void MainWindow::showEvent(QShowEvent *event)
-{
-    updateWidgetsPosition();
-
-    return FramelessWindow::showEvent(event);
-}
-
-void MainWindow::enterEvent(QEnterEvent *event)
-{
-    return FramelessWindow::enterEvent(event);
-}
-
-void MainWindow::leaveEvent(QEvent *event)
-{
-    return FramelessWindow::leaveEvent(event);
-}
-
-void MainWindow::mouseDoubleClickEvent(QMouseEvent *event)
-{
-    // The forward/back mouse button can also used to trigger a mouse double-click event
-    // Since we use that for gallery navigation so we ignore these two buttons.
-    if (event->buttons() & Qt::ForwardButton || event->buttons() & Qt::BackButton) {
-        return;
-    }
-
-    switch (Settings::instance()->doubleClickBehavior()) {
-    case Settings::DoubleClickBehavior::Close:
-        quitAppAction();
-        event->accept();
-        break;
-    case Settings::DoubleClickBehavior::Maximize:
-        toggleMaximize();
-        event->accept();
-        break;
-    case Settings::DoubleClickBehavior::FullScreen:
-        toggleFullscreen();
-        event->accept();
-        break;
-    case Settings::DoubleClickBehavior::Ignore:
-        break;
-    }
-
-    // blumia: don't call parent constructor here, seems it will cause mouse move
-    //         event get called even if we set event->accept();
-    // return QMainWindow::mouseDoubleClickEvent(event);
-}
-
 void MainWindow::wheelEvent(QWheelEvent *event)
 {
     QPoint numDegrees = event->angleDelta() / 8;
@@ -347,94 +294,26 @@ void MainWindow::wheelEvent(QWheelEvent *event)
         }
         event->accept();
     } else {
-        FramelessWindow::wheelEvent(event);
+        QWidget::wheelEvent(event);
     }
 }
 
-void MainWindow::resizeEvent(QResizeEvent *event)
-{
-    updateWidgetsPosition();
-
-    return FramelessWindow::resizeEvent(event);
-}
-
 void MainWindow::contextMenuEvent(QContextMenuEvent *event)
 {
-    QMenu * menu = new QMenu;
-    QMenu * copyMenu = new QMenu(tr("&Copy"));
-    QUrl currentFileUrl = currentImageFileUrl();
+    ui->m_menu->exec(mapToGlobal(event->pos()));
 
-    QAction * copyPixmap = m_am->actionCopyPixmap;
-    QAction * copyFilePath = m_am->actionCopyFilePath;
-
-    copyMenu->setIcon(QIcon::fromTheme(u"edit-copy"_s));
-    copyMenu->addAction(copyPixmap);
-    if (currentFileUrl.isValid()) {
-        copyMenu->addAction(copyFilePath);
-    }
-
-    QAction * paste = m_am->actionPaste;
-
-    QAction * trash = m_am->actionTrash;
-
-    QAction * avoidResetTransform = m_am->actionToggleAvoidResetTransform;
-    avoidResetTransform->setCheckable(true);
-    avoidResetTransform->setChecked(m_gv->avoidResetTransform());
-
-    QAction * toggleSettings = m_am->actionSettings;
-    QAction * helpAction = m_am->actionHelp;
-    QAction * propertiesAction = m_am->actionProperties;
-
-#if 0
-    menu->addAction(m_am->actionOpen);
-#endif // 0
-
-    if (copyMenu->actions().count() == 1) {
-        menu->addActions(copyMenu->actions());
-    } else {
-        menu->addMenu(copyMenu);
-    }
-
-    if (canPaste()) {
-        menu->addAction(paste);
-    }
-
-    menu->addSeparator();
-
-    menu->addAction(m_am->actionHorizontalFlip);
-#if 0
-    menu->addAction(m_am->actionFitInView);
-    menu->addAction(m_am->actionFitByWidth);
-#endif // 0
-    menu->addSeparator();
-    menu->addAction(avoidResetTransform);
-    menu->addSeparator();
-    menu->addAction(toggleSettings);
-    menu->addAction(helpAction);
-    if (currentFileUrl.isValid()) {
-        menu->addSeparator();
-        if (currentFileUrl.isLocalFile()) {
-            menu->addAction(trash);
-            menu->addAction(m_am->actionLocateInFileManager);
-        }
-        menu->addAction(propertiesAction);
-    }
-    menu->exec(mapToGlobal(event->pos()));
-    menu->deleteLater();
-    copyMenu->deleteLater();
-
-    return FramelessWindow::contextMenuEvent(event);
+    return QWidget::contextMenuEvent(event);
 }
 
 void MainWindow::dragEnterEvent(QDragEnterEvent *event)
 {
-    if (event->mimeData()->hasUrls() || event->mimeData()->hasImage() || event->mimeData()->hasText()) {
+    if (event->mimeData()->hasUrls()) {
         event->acceptProposedAction();
     } else {
         event->ignore();
     }
 
-    return FramelessWindow::dragEnterEvent(event);
+    return QWidget::dragEnterEvent(event);
 }
 
 void MainWindow::dragMoveEvent(QDragMoveEvent *event)
@@ -447,26 +326,10 @@ void MainWindow::dropEvent(QDropEvent *event)
     event->acceptProposedAction();
 
     const QMimeData * mimeData = event->mimeData();
-
     if (mimeData->hasUrls()) {
-        const QList<QUrl> &urls = mimeData->urls();
-        if (urls.isEmpty()) {
-            m_gv->showText(tr("File url list is empty"));
+        showFiles(mimeData->urls());
     } else {
-            showUrls(urls);
-        }
-    } else if (mimeData->hasImage()) {
-        QImage img = qvariant_cast<QImage>(mimeData->imageData());
-        QPixmap pixmap = QPixmap::fromImage(img);
-        if (pixmap.isNull()) {
-            m_gv->showText(tr("Image data is invalid"));
-        } else {
-            m_gv->showImage(pixmap);
-        }
-    } else if (mimeData->hasText()) {
-        m_gv->showText(mimeData->text());
-    } else {
-        m_gv->showText(tr("Not supported mimedata: %1").arg(mimeData->formats().first()));
+        ui->m_gv->showText(tr("Not supported mimedata: %1").arg(mimeData->formats().first()));
     }
 }
 
@@ -482,43 +345,9 @@ void MainWindow::centerWindow()
     );
 }
 
-void MainWindow::closeWindow()
-{
-}
-
-void MainWindow::updateWidgetsPosition()
-{
-    m_bottomButtonGroup->move((width() - m_bottomButtonGroup->width()) / 2,
-                              (72 - m_bottomButtonGroup->height()) / 2 + (height() - 72));
-    m_nav->move(width() - m_nav->width(), height() - m_nav->height());
-}
-
 void MainWindow::toggleAvoidResetTransform()
 {
-    m_gv->setAvoidResetTransform(!m_gv->avoidResetTransform());
-}
-
-bool MainWindow::canPaste() const
-{
-    const QMimeData * clipboardData = QApplication::clipboard()->mimeData();
-    if (clipboardData->hasImage()) {
-        return true;
-    } else if (clipboardData->hasText()) {
-        QString clipboardText(clipboardData->text());
-        if (clipboardText.startsWith("PICTURE:")) {
-            QString maybeFilename(clipboardText.mid(8));
-            if (QFile::exists(maybeFilename)) {
-                return true;
-            }
-        }
-    }
-
-    return false;
-}
-
-void MainWindow::quitAppAction(bool force)
-{
-    closeWindow();
+    ui->m_gv->setAvoidResetTransform(!ui->m_gv->isAvoidResetTransform());
 }
 
 void MainWindow::toggleFullscreen()
@@ -544,140 +373,21 @@ QSize MainWindow::sizeHint() const
     return QSize(710, 530);
 }
 
-void MainWindow::on_actionOpen_triggered()
-{
-    QStringList picturesLocations = QStandardPaths::standardLocations(QStandardPaths::PicturesLocation);
-    QUrl pictureUrl = picturesLocations.isEmpty() ? QUrl::fromLocalFile(picturesLocations.first())
-                                                  : QUrl::fromLocalFile(QDir::homePath());
-    QList<QUrl> urls(QFileDialog::getOpenFileUrls(this, QString(), pictureUrl));
-    if (!urls.isEmpty()) {
-        showUrls(urls);
-    }
-}
-
-void MainWindow::on_actionActualSize_triggered()
-{
-    m_gv->resetScale();
-    m_gv->setEnableAutoFitInView(false);
-}
-
-void MainWindow::on_actionToggleMaximize_triggered()
-{
-    toggleMaximize();
-}
-
-void MainWindow::on_actionZoomIn_triggered()
-{
-    if (m_gv->scaleFactor() < 1000) {
-        m_gv->zoomView(1.25);
-    }
-}
-
-void MainWindow::on_actionZoomOut_triggered()
-{
-    m_gv->zoomView(0.8);
-}
-
-void MainWindow::on_actionHorizontalFlip_triggered()
-{
-    m_gv->flipView();
-}
-
-void MainWindow::on_actionFitInView_triggered()
-{
-    m_gv->fitInView(m_nav->sceneRect(), Qt::KeepAspectRatio);
-    m_gv->setEnableAutoFitInView(m_gv->scaleFactor() <= 1);
-}
-
-void MainWindow::on_actionFitByWidth_triggered()
-{
-    m_gv->fitByOrientation();
-}
+// region: Action Trigger
 
 void MainWindow::on_actionCopyPixmap_triggered()
 {
     QClipboard *cb = QApplication::clipboard();
-    cb->setPixmap(m_gv->scene()->renderToPixmap());
+    cb->setPixmap(ui->m_gv->scene()->renderToPixmap());
 }
 
 void MainWindow::on_actionCopyFilePath_triggered()
 {
-    QUrl currentFileUrl(currentImageFileUrl());
-    if (currentFileUrl.isValid()) {
+    auto index = m_pm->currentIndex();
+    if (!index.has_value()) return;
+
     QClipboard *cb = QApplication::clipboard();
-        cb->setText(currentFileUrl.toLocalFile());
-    }
-}
-
-void MainWindow::on_actionPaste_triggered()
-{
-    QImage clipboardImage;
-    QUrl clipboardFileUrl;
-
-    const QMimeData * clipboardData = QApplication::clipboard()->mimeData();
-    if (clipboardData->hasImage()) {
-        QVariant imageVariant(clipboardData->imageData());
-        if (imageVariant.isValid()) {
-            clipboardImage = qvariant_cast<QImage>(imageVariant);
-        }
-    } else if (clipboardData->hasText()) {
-        QString clipboardText(clipboardData->text());
-        if (clipboardText.startsWith("PICTURE:")) {
-            QString maybeFilename(clipboardText.mid(8));
-            if (QFile::exists(maybeFilename)) {
-                clipboardFileUrl = QUrl::fromLocalFile(maybeFilename);
-            }
-        }
-    }
-
-    if (!clipboardImage.isNull()) {
-        setWindowTitle(tr("Image From Clipboard"));
-        m_gv->showImage(clipboardImage);
-        clearGallery();
-    } else if (clipboardFileUrl.isValid()) {
-        m_gv->showFileFromPath(clipboardFileUrl.toLocalFile());
-        m_pm->loadPlaylist(clipboardFileUrl);
-    }
-}
-
-void MainWindow::on_actionTrash_triggered()
-{
-    QModelIndex index = m_pm->curIndex();
-    if (!m_pm->urlByIndex(index).isLocalFile()) return;
-
-    QFile file(m_pm->localFileByIndex(index));
-    QFileInfo fileInfo(file.fileName());
-
-    QMessageBox::StandardButton result = QMessageBox::question(this, tr("Move to Trash"),
-                                                               tr("Are you sure you want to move \"%1\" to recycle bin?").arg(fileInfo.fileName()));
-    if (result == QMessageBox::Yes) {
-        bool succ = file.moveToTrash();
-        if (!succ) {
-            QMessageBox::warning(this, tr("Failed to move file to trash"),
-                                 tr("Move to trash failed, it might caused by file permission issue, file system limitation, or platform limitation."));
-        } else {
-            m_pm->removeAt(index);
-            galleryCurrent(true, true);
-        }
-    }
-}
-
-void MainWindow::on_actionToggleCheckerboard_triggered()
-{
-    // TODO: is that okay to do this since we plan to support custom shortcuts?
-    m_gv->toggleCheckerboard(QGuiApplication::queryKeyboardModifiers().testFlag(Qt::ShiftModifier));
-}
-
-void MainWindow::on_actionRotateClockwise_triggered()
-{
-    m_gv->rotateView();
-    m_gv->displayScene();
-}
-
-void MainWindow::on_actionRotateCounterClockwise_triggered()
-{
-    m_gv->rotateView(false);
-    m_gv->displayScene();
+    cb->setText(m_pm->localFileByIndex(*index));
 }
 
 void MainWindow::on_actionPrevPicture_triggered()
@@ -690,14 +400,60 @@ void MainWindow::on_actionNextPicture_triggered()
     galleryNext();
 }
 
-void MainWindow::on_actionTogglePauseAnimation_triggered()
+void MainWindow::on_actionActualSize_triggered()
 {
-    m_gv->scene()->togglePauseAnimation();
+    ui->m_gv->resetScale();
+    ui->m_gv->setEnableAutoFitToScreen(false);
 }
 
-void MainWindow::on_actionAnimationNextFrame_triggered()
+void MainWindow::on_actionFitToScreen_triggered()
 {
-    m_gv->scene()->skipAnimationFrame(1);
+    ui->m_gv->fitInView(ui->m_nav->sceneRect(), Qt::KeepAspectRatio);
+    ui->m_gv->setEnableAutoFitToScreen(ui->m_gv->scaleFactor() <= 1);
+}
+
+void MainWindow::on_actionFitByWidth_triggered()
+{
+    ui->m_gv->fitByOrientation(Qt::Orientation::Horizontal);
+}
+
+void MainWindow::on_actionFitByHeight_triggered()
+{
+    ui->m_gv->fitByOrientation(Qt::Orientation::Vertical);
+}
+
+void MainWindow::on_actionZoomIn_triggered()
+{
+    if (ui->m_gv->scaleFactor() < 1000) {
+        ui->m_gv->zoomView(1.25);
+    }
+}
+
+void MainWindow::on_actionZoomOut_triggered()
+{
+    ui->m_gv->zoomView(0.8);
+}
+
+void MainWindow::on_actionFlipHorizontal_triggered()
+{
+    ui->m_gv->flipView(true);
+}
+
+void MainWindow::on_actionFlipVertical_triggered()
+{
+    ui->m_gv->flipView(false);
+}
+
+void MainWindow::on_actionRotateClockwise_triggered()
+{
+    ui->m_gv->rotateView(true);
+    ui->m_gv->displayScene();
+}
+
+void MainWindow::on_actionRotateCounterClockwise_triggered()
+{
+    ui->m_gv->rotateView(false);
+    ui->m_gv->displayScene();
 }
 
 void MainWindow::on_actionToggleAvoidResetTransform_triggered()
@@ -705,37 +461,48 @@ void MainWindow::on_actionToggleAvoidResetTransform_triggered()
     toggleAvoidResetTransform();
 }
 
-void MainWindow::on_actionSettings_triggered()
+void MainWindow::on_actionToggleCheckerboard_triggered()
 {
-    SettingsDialog * sd = new SettingsDialog(this);
-    sd->exec();
-    sd->deleteLater();
+    ui->m_gv->toggleCheckerboard(QGuiApplication::queryKeyboardModifiers().testFlag(Qt::ShiftModifier));
 }
 
-void MainWindow::on_actionHelp_triggered()
+void MainWindow::on_actionTogglePauseAnimation_triggered()
 {
-    AboutDialog * ad = new AboutDialog(this);
-    ad->exec();
-    ad->deleteLater();
+    ui->m_gv->scene()->togglePauseAnimation();
 }
 
-void MainWindow::on_actionProperties_triggered()
+void MainWindow::on_actionAnimationNextFrame_triggered()
 {
-    QUrl currentFileUrl = currentImageFileUrl();
-    if (!currentFileUrl.isValid()) return;
+    ui->m_gv->scene()->skipAnimationFrame(1);
+}
 
-    MetadataModel * md = new MetadataModel();
-    md->setFile(currentFileUrl.toLocalFile());
+void MainWindow::on_actionTrash_triggered()
+{
+    auto index = m_pm->currentIndex();
+    if (!index.has_value()) return;
+    if (!m_pm->urlByIndex(*index).isLocalFile()) return;
 
-    MetadataDialog * ad = new MetadataDialog(this);
-    ad->setMetadataModel(md);
-    ad->exec();
-    ad->deleteLater();
+    QFile file(m_pm->localFileByIndex(*index));
+    QFileInfo fileInfo(file.fileName());
+
+    QMessageBox::StandardButton result = QMessageBox::question(this, tr("Move to Trash"),
+                                                               tr("Are you sure you want to move \"%1\" to recycle bin?").arg(fileInfo.fileName()));
+    if (result == QMessageBox::Yes) {
+        bool succ = file.moveToTrash();
+        if (!succ) {
+            QMessageBox::warning(this, tr("Failed to move file to trash"),
+                                 tr("Move to trash failed, it might caused by file permission issue, file system limitation, or platform limitation."));
+        } else {
+            m_pm->removeFromPlaylist(*index);
+        }
+    }
 }
 
 void MainWindow::on_actionLocateInFileManager_triggered()
 {
-    QUrl currentFileUrl = currentImageFileUrl();
+    auto index = m_pm->currentIndex();
+    if (!index.has_value()) return;
+    QUrl currentFileUrl = m_pm->urlByIndex(*index);
     if (!currentFileUrl.isValid()) return;
 
     QFileInfo fileInfo(currentFileUrl.toLocalFile());
@@ -768,11 +535,38 @@ void MainWindow::on_actionLocateInFileManager_triggered()
 #endif // Q_OS_WIN
 }
 
-void MainWindow::on_actionQuitApp_triggered()
+void MainWindow::on_actionProperties_triggered()
 {
-    quitAppAction(false);
+    auto index = m_pm->currentIndex();
+    if (!index.has_value()) return;
+    QUrl currentFileUrl = m_pm->urlByIndex(*index);
+    if (!currentFileUrl.isValid()) return;
+
+    MetadataModel * md = new MetadataModel();
+    md->setFile(currentFileUrl.toLocalFile());
+
+    MetadataDialog * ad = new MetadataDialog(this);
+    ad->setMetadataModel(md);
+    ad->exec();
+    ad->deleteLater();
 }
 
+void MainWindow::on_actionSettings_triggered()
+{
+    SettingsDialog * sd = new SettingsDialog(this);
+    sd->exec();
+    sd->deleteLater();
+}
+
+void MainWindow::on_actionHelp_triggered()
+{
+    AboutDialog * ad = new AboutDialog(this);
+    ad->exec();
+    ad->deleteLater();
+}
+
+// endregion
+
 bool MainWindow::updateFileWatcher(const QString &basePath)
 {
     m_fileSystemWatcher->removePaths(m_fileSystemWatcher->files());
@@ -780,11 +574,6 @@ bool MainWindow::updateFileWatcher(const QString &basePath)
     return false;
 }
 
-void MainWindow::updateGalleryButtonsVisibility()
-{
-    const int galleryFileCount = m_pm->totalCount();
-    const bool loopGallery = Settings::instance()->loopGallery();
-    m_am->enablePrevNextPictureAction(
-        galleryFileCount > 1 && (loopGallery || !m_pm->isFirstIndex()),
-        galleryFileCount > 1 && (loopGallery || !m_pm->isLastIndex()));
+void MainWindow::updateActionState() {
+    m_am->updateActionState(m_pm, ui->m_gv);
 }

app/mainwindow.h

@@ -5,23 +5,19 @@
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
 
-#include "framelesswindow.h"
-
-#include <QParallelAnimationGroup>
-#include <QPropertyAnimation>
-#include <QPushButton>
+#include <QWidget>
 
 QT_BEGIN_NAMESPACE
-class QGraphicsView;
 class QFileSystemWatcher;
+namespace Ui {
+class MainWindow;
+}
 QT_END_NAMESPACE
 
 class ActionManager;
 class PlaylistManager;
-class GraphicsView;
-class NavigatorView;
-class BottomButtonGroup;
-class MainWindow : public FramelessWindow
+
+class MainWindow : public QWidget
 {
     Q_OBJECT
 
@@ -29,36 +25,26 @@ public:
     explicit MainWindow(QWidget *parent = nullptr);
     ~MainWindow() override;
 
-    void showUrls(const QList<QUrl> &urls);
+    void showFiles(const QStringList& files);
+    void showFiles(const QList<QUrl>& urls);
     void initWindowSize();
-    void adjustWindowSizeBySceneRect();
-    QUrl currentImageFileUrl() const;
 
     void clearGallery();
     void galleryPrev();
     void galleryNext();
-    void galleryCurrent(bool showLoadImageHintWhenEmpty, bool reloadImage);
+    void galleryCurrent(bool fromFileWatcher);
 
     static QStringList supportedImageFormats();
 
 protected slots:
-    void showEvent(QShowEvent *event) override;
-    void enterEvent(QEnterEvent *event) override;
-    void leaveEvent(QEvent *event) override;
-    void mouseDoubleClickEvent(QMouseEvent *event) override;
     void wheelEvent(QWheelEvent *event) override;
-    void resizeEvent(QResizeEvent *event) override;
     void contextMenuEvent(QContextMenuEvent *event) override;
     void dragEnterEvent(QDragEnterEvent *event) override;
     void dragMoveEvent(QDragMoveEvent *event) override;
     void dropEvent(QDropEvent *event) override;
 
     void centerWindow();
-    void closeWindow();
-    void updateWidgetsPosition();
     void toggleAvoidResetTransform();
-    bool canPaste() const;
-    void quitAppAction(bool force = false);
     void toggleFullscreen();
     void toggleMaximize();
 
@@ -66,48 +52,46 @@ protected:
     QSize sizeHint() const override;
 
 private slots:
-    void on_actionOpen_triggered();
-
-    void on_actionActualSize_triggered();
-    void on_actionToggleMaximize_triggered();
-    void on_actionZoomIn_triggered();
-    void on_actionZoomOut_triggered();
-    void on_actionToggleCheckerboard_triggered();
-    void on_actionRotateClockwise_triggered();
-    void on_actionRotateCounterClockwise_triggered();
+    void on_actionCopyPixmap_triggered();
+    void on_actionCopyFilePath_triggered();
 
     void on_actionPrevPicture_triggered();
     void on_actionNextPicture_triggered();
 
+    void on_actionActualSize_triggered();
+    void on_actionFitToScreen_triggered();
+    void on_actionFitByWidth_triggered();
+    void on_actionFitByHeight_triggered();
+    void on_actionZoomIn_triggered();
+    void on_actionZoomOut_triggered();
+
+    void on_actionFlipHorizontal_triggered();
+    void on_actionFlipVertical_triggered();
+    void on_actionRotateClockwise_triggered();
+    void on_actionRotateCounterClockwise_triggered();
+
+    void on_actionToggleAvoidResetTransform_triggered();
+    void on_actionToggleCheckerboard_triggered();
     void on_actionTogglePauseAnimation_triggered();
     void on_actionAnimationNextFrame_triggered();
 
-    void on_actionHorizontalFlip_triggered();
-    void on_actionFitInView_triggered();
-    void on_actionFitByWidth_triggered();
-    void on_actionCopyPixmap_triggered();
-    void on_actionCopyFilePath_triggered();
-    void on_actionPaste_triggered();
     void on_actionTrash_triggered();
-    void on_actionToggleAvoidResetTransform_triggered();
+    void on_actionLocateInFileManager_triggered();
+    void on_actionProperties_triggered();
+
     void on_actionSettings_triggered();
     void on_actionHelp_triggered();
-    void on_actionProperties_triggered();
-    void on_actionLocateInFileManager_triggered();
-    void on_actionQuitApp_triggered();
 
 private:
     bool updateFileWatcher(const QString & basePath = QString());
-    void updateGalleryButtonsVisibility();
+    void updateActionState();
 
 private:
+    QT_PREPEND_NAMESPACE(Ui::MainWindow) *ui;
+    
     ActionManager *m_am;
     PlaylistManager *m_pm;
-    GraphicsView *m_gv;
-    NavigatorView *m_nav;
-
     QFileSystemWatcher *m_fileSystemWatcher;
-    BottomButtonGroup *m_bottomButtonGroup;
 };
 
 #endif // MAINWINDOW_H

app/mainwindow.ui

@@ -0,0 +1,172 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>MainWindow</class>
+ <widget class="QWidget" name="MainWindow">
+  <property name="windowModality">
+   <enum>Qt::NonModal</enum>
+  </property>
+  <property name="minimumSize">
+   <size>
+    <width>640</width>
+    <height>480</height>
+   </size>
+  </property>
+  <property name="acceptDrops">
+   <bool>true</bool>
+  </property>
+  <layout class="QVBoxLayout" name="m_centralLayout">
+   <property name="spacing">
+    <number>0</number>
+   </property>
+   <property name="leftMargin">
+    <number>0</number>
+   </property>
+   <property name="topMargin">
+    <number>0</number>
+   </property>
+   <property name="rightMargin">
+    <number>0</number>
+   </property>
+   <property name="bottomMargin">
+    <number>0</number>
+   </property>
+   <item>
+    <widget class="GraphicsView" name="m_gv">
+     <property name="frameShape">
+      <enum>QFrame::NoFrame</enum>
+     </property>
+     <property name="verticalScrollBarPolicy">
+      <enum>Qt::ScrollBarAlwaysOff</enum>
+     </property>
+     <property name="horizontalScrollBarPolicy">
+      <enum>Qt::ScrollBarAlwaysOff</enum>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <widget class="QWidget" name="bottomBar" native="true">
+     <property name="minimumSize">
+      <size>
+       <width>0</width>
+       <height>72</height>
+      </size>
+     </property>
+     <property name="maximumSize">
+      <size>
+       <width>16777215</width>
+       <height>72</height>
+      </size>
+     </property>
+     <layout class="QHBoxLayout" name="bottomBarLayout">
+      <property name="spacing">
+       <number>0</number>
+      </property>
+      <property name="leftMargin">
+       <number>0</number>
+      </property>
+      <property name="topMargin">
+       <number>0</number>
+      </property>
+      <property name="rightMargin">
+       <number>0</number>
+      </property>
+      <property name="bottomMargin">
+       <number>0</number>
+      </property>
+      <item>
+       <widget class="QWidget" name="m_navPH" native="true">
+        <property name="minimumSize">
+         <size>
+          <width>99</width>
+          <height>72</height>
+         </size>
+        </property>
+        <property name="maximumSize">
+         <size>
+          <width>99</width>
+          <height>72</height>
+         </size>
+        </property>
+       </widget>
+      </item>
+      <item>
+       <spacer name="leftSpacer">
+        <property name="orientation">
+         <enum>Qt::Horizontal</enum>
+        </property>
+       </spacer>
+      </item>
+      <item>
+       <widget class="BottomButtonGroup" name="m_bottomButtonGroup"/>
+      </item>
+      <item>
+       <spacer name="rightSpacer">
+        <property name="orientation">
+         <enum>Qt::Horizontal</enum>
+        </property>
+       </spacer>
+      </item>
+      <item>
+       <widget class="NavigatorView" name="m_nav">
+        <property name="minimumSize">
+         <size>
+          <width>99</width>
+          <height>72</height>
+         </size>
+        </property>
+        <property name="maximumSize">
+         <size>
+          <width>99</width>
+          <height>72</height>
+         </size>
+        </property>
+        <property name="frameShape">
+         <enum>QFrame::NoFrame</enum>
+        </property>
+        <property name="verticalScrollBarPolicy">
+         <enum>Qt::ScrollBarAlwaysOff</enum>
+        </property>
+        <property name="horizontalScrollBarPolicy">
+         <enum>Qt::ScrollBarAlwaysOff</enum>
+        </property>
+       </widget>
+      </item>
+     </layout>
+    </widget>
+   </item>
+  </layout>
+  <widget class="QMenu" name="m_subMenuCopy">
+   <property name="title">
+    <string>&amp;Copy</string>
+   </property>
+   <property name="icon">
+    <iconset theme="edit-copy"/>
+   </property>
+  </widget>
+  <widget class="QMenu" name="m_subMenuTransform">
+   <property name="title">
+    <string>&amp;Transform</string>
+   </property>
+  </widget>
+  <widget class="QMenu" name="m_menu"/>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>GraphicsView</class>
+   <extends>QGraphicsView</extends>
+   <header>graphicsview.h</header>
+  </customwidget>
+  <customwidget>
+   <class>NavigatorView</class>
+   <extends>QGraphicsView</extends>
+   <header>navigatorview.h</header>
+  </customwidget>
+  <customwidget>
+   <class>BottomButtonGroup</class>
+   <extends>QGroupBox</extends>
+   <header>bottombuttongroup.h</header>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections/>
+</ui>

app/metadatadialog.cpp

@@ -3,12 +3,12 @@
 // SPDX-License-Identifier: MIT
 
 #include "metadatadialog.h"
+#include "ui_metadatadialog.h"
 
 #include <QDialogButtonBox>
 #include <QPainter>
 #include <QStyledItemDelegate>
 #include <QTreeView>
-#include <QVBoxLayout>
 #include <QHeaderView>
 
 #include "metadatamodel.h"
@@ -73,30 +73,33 @@ protected:
 };
 
 MetadataDialog::MetadataDialog(QWidget *parent)
-    : QDialog(parent)
-    , m_treeView(new PropertyTreeView(this))
+    : QDialog(parent), ui(new QT_PREPEND_NAMESPACE(Ui::MetadataDialog))
 {
+    ui->setupUi(this);
+    setWindowFlag(Qt::WindowContextHelpButtonHint, false);
+
+    // YYC MARK:
+    // Because we use custom QTreeView and we do not want to expose it to public domain.
+    // So I have to use this way as the compromise.
+
+    // Create our custom QTreeView and insert them
+    m_treeView = new PropertyTreeView(this);
+    auto* layout = ui->verticalLayout;
+    const int index = layout->indexOf(ui->m_buttonBox);
+    layout->insertWidget(index, m_treeView);
+
+    // Setup our custom QTreeView
     m_treeView->setRootIsDecorated(false);
     m_treeView->setIndentation(0);
     m_treeView->setItemDelegate(new PropertyTreeItemDelegate(m_treeView));
     m_treeView->header()->resizeSection(0, sizeHint().width() / 2);
 
-    setWindowTitle(tr("Image Metadata"));
-
-    QDialogButtonBox * buttonBox = new QDialogButtonBox(QDialogButtonBox::Close);
-
-    setLayout(new QVBoxLayout);
-    layout()->addWidget(m_treeView);
-    layout()->addWidget(buttonBox);
-
-    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::close);
-
-    setWindowFlag(Qt::WindowContextHelpButtonHint, false);
+    connect(ui->m_buttonBox, &QDialogButtonBox::rejected, this, &QDialog::close);
 }
 
 MetadataDialog::~MetadataDialog()
 {
-
+    delete ui;
 }
 
 void MetadataDialog::setMetadataModel(MetadataModel * model)

app/metadatadialog.h

@@ -11,6 +11,12 @@ QT_BEGIN_NAMESPACE
 class QTreeView;
 QT_END_NAMESPACE
 
+QT_BEGIN_NAMESPACE
+namespace Ui {
+class MetadataDialog;
+}
+QT_END_NAMESPACE
+
 class MetadataModel;
 class MetadataDialog : public QDialog
 {
@@ -25,6 +31,7 @@ public:
 
 private:
     QTreeView * m_treeView = nullptr;
+    QT_PREPEND_NAMESPACE(Ui::MetadataDialog) *ui;
 };
 
 #endif // METADATADIALOG_H

app/metadatadialog.ui

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>MetadataDialog</class>
+ <widget class="QDialog" name="MetadataDialog">
+  <property name="windowModality">
+   <enum>Qt::NonModal</enum>
+  </property>
+  <property name="windowTitle">
+   <string>Image Metadata</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <widget class="QDialogButtonBox" name="m_buttonBox">
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Close</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

app/navigatorview.cpp

@@ -6,6 +6,8 @@
 
 #include "graphicsview.h"
 
+#include <QStyleHints>
+#include <QOperatingSystemVersion>
 #include <QMouseEvent>
 #include <QDebug>
 #include <QTimer>
@@ -16,8 +18,9 @@ NavigatorView::NavigatorView(QWidget *parent)
 {
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
-    setStyleSheet("background-color: rgba(0, 0, 0, 120);"
-                  "border-radius: 3px;");
+
+    updateStyle(qGuiApp->styleHints()->colorScheme());
+    connect(qGuiApp->styleHints(), &QStyleHints::colorSchemeChanged, this, &NavigatorView::updateStyle);
 }
 
 // doesn't take or manage its ownership
@@ -38,6 +41,39 @@ void NavigatorView::updateMainViewportRegion()
     });
 }
 
+void NavigatorView::updateStyle(Qt::ColorScheme colorScheme) {
+    // YYC MARK:
+    // If we are using Windows 10 and lower system or Qt which do not support "Windows 11"
+    // theme (lower than Qt 6.7), we should only support light mode.
+    // Because Qt's dark-mode-aware "Windows 11" theme is only well-supported on Windows 11.
+#if defined(Q_OS_WIN)
+#if QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
+    colorScheme = Qt::ColorScheme::Light;
+#else
+    if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows11) {
+        colorScheme = Qt::ColorScheme::Light;
+    }
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
+#endif // defined(Q_OS_WIN)
+
+    switch (colorScheme) {
+    case Qt::ColorScheme::Dark:
+    setStyleSheet(R"#(
+border-style: none;
+background-color: rgba(255, 255, 255, 70);
+)#");
+        break;
+    case Qt::ColorScheme::Light:
+    case Qt::ColorScheme::Unknown:
+    default:
+        setStyleSheet(R"#(
+border-style: none;
+background-color: rgba(0, 0, 0, 70);
+)#");
+        break;
+    }
+}
+
 void NavigatorView::mousePressEvent(QMouseEvent *event)
 {
     m_mouseDown = true;

app/navigatorview.h

@@ -19,6 +19,9 @@ public:
 public slots:
     void updateMainViewportRegion();
 
+private slots:
+    void updateStyle(Qt::ColorScheme colorScheme);
+
 private:
     void mousePressEvent(QMouseEvent * event) override;
     void mouseMoveEvent(QMouseEvent * event) override;

app/playlistmanager.cpp

@@ -3,158 +3,20 @@
 // SPDX-License-Identifier: MIT
 
 #include "playlistmanager.h"
+#include "playlistscout.h"
 
 #include <QCollator>
 #include <QDir>
 #include <QFileInfo>
 #include <QUrl>
 
-PlaylistModel::PlaylistModel(QObject *parent)
-    : QAbstractListModel(parent)
-{
-
-}
-
-PlaylistModel::~PlaylistModel()
-= default;
-
-void PlaylistModel::setPlaylist(const QList<QUrl> &urls)
-{
-    beginResetModel();
-    m_playlist = urls;
-    endResetModel();
-}
-
-QModelIndex PlaylistModel::loadPlaylist(const QList<QUrl> & urls)
-{
-    if (urls.isEmpty()) return {};
-    if (urls.count() == 1) {
-        return loadPlaylist(urls.constFirst());
-    } else {
-        setPlaylist(urls);
-        return index(0);
-    }
-}
-
-QModelIndex PlaylistModel::loadPlaylist(const QUrl &url)
-{
-    QFileInfo info(url.toLocalFile());
-    QDir dir(info.path());
-    QString && currentFileName = info.fileName();
-
-    if (dir.path() == m_currentDir) {
-        int idx = indexOf(url);
-        return idx == -1 ? appendToPlaylist(url) : index(idx);
-    }
-
-    QStringList entryList = dir.entryList(
-        m_autoLoadSuffixes,
-        QDir::Files | QDir::NoSymLinks, QDir::NoSort);
-
-    QCollator collator;
-    collator.setNumericMode(true);
-
-    std::sort(entryList.begin(), entryList.end(), collator);
-
-    QList<QUrl> playlist;
-
-    int idx = -1;
-    for (int i = 0; i < entryList.count(); i++) {
-        const QString & fileName = entryList.at(i);
-        const QString & oneEntry = dir.absoluteFilePath(fileName);
-        const QUrl & url = QUrl::fromLocalFile(oneEntry);
-        playlist.append(url);
-        if (fileName == currentFileName) {
-            idx = i;
-        }
-    }
-    if (idx == -1) {
-        idx = playlist.count();
-        playlist.append(url);
-    }
-    m_currentDir = dir.path();
-
-    setPlaylist(playlist);
-
-    return index(idx);
-}
-
-QModelIndex PlaylistModel::appendToPlaylist(const QUrl &url)
-{
-    const int lastIndex = rowCount();
-    beginInsertRows(QModelIndex(), lastIndex, lastIndex);
-    m_playlist.append(url);
-    endInsertRows();
-    return index(lastIndex);
-}
-
-bool PlaylistModel::removeAt(int index)
-{
-    if (index < 0 || index >= rowCount()) return false;
-    beginRemoveRows(QModelIndex(), index, index);
-    m_playlist.removeAt(index);
-    endRemoveRows();
-    return true;
-}
-
-int PlaylistModel::indexOf(const QUrl &url) const
-{
-    return m_playlist.indexOf(url);
-}
-
-QUrl PlaylistModel::urlByIndex(int index) const
-{
-    return m_playlist.value(index);
-}
-
-QStringList PlaylistModel::autoLoadFilterSuffixes() const
-{
-    return m_autoLoadSuffixes;
-}
-
-QHash<int, QByteArray> PlaylistModel::roleNames() const
-{
-    QHash<int, QByteArray> result = QAbstractListModel::roleNames();
-    result.insert(UrlRole, "url");
-    return result;
-}
-
-int PlaylistModel::rowCount(const QModelIndex &parent) const
-{
-    return m_playlist.count();
-}
-
-QVariant PlaylistModel::data(const QModelIndex &index, int role) const
-{
-    if (!index.isValid()) return {};
-
-    switch (role) {
-    case Qt::DisplayRole:
-        return m_playlist.at(index.row()).fileName();
-    case UrlRole:
-        return m_playlist.at(index.row());
-    }
-
-    return {};
-}
-
 PlaylistManager::PlaylistManager(QObject *parent)
     : QObject(parent)
+    , m_currentIndex(std::nullopt)
+    , m_playlist()
+    , m_allowedSuffixes()
 {
-    connect(&m_model, &PlaylistModel::rowsRemoved, this,
-            [this](const QModelIndex &, int, int) {
-                if (m_model.rowCount() <= m_currentIndex) {
-                    setProperty("currentIndex", m_currentIndex - 1);
-                }
-            });
 
-    auto onRowCountChanged = [this](){
-        emit totalCountChanged(m_model.rowCount());
-    };
-
-    connect(&m_model, &PlaylistModel::rowsInserted, this, onRowCountChanged);
-    connect(&m_model, &PlaylistModel::rowsRemoved, this, onRowCountChanged);
-    connect(&m_model, &PlaylistModel::modelReset, this, onRowCountChanged);
 }
 
 PlaylistManager::~PlaylistManager()
@@ -162,35 +24,86 @@ PlaylistManager::~PlaylistManager()
 
 }
 
-PlaylistModel *PlaylistManager::model()
-{
-    return &m_model;
+// region: Allowed Suffixes Operations
+
+const QStringList& PlaylistManager::allowedSuffixes() const {
+    return m_allowedSuffixes;
 }
 
-void PlaylistManager::setPlaylist(const QList<QUrl> &urls)
-{
-    m_model.setPlaylist(urls);
+void PlaylistManager::setAllowedSuffixes(const QStringList& nameFilters) {
+    m_allowedSuffixes = nameFilters;
+    emit allowedSuffixesChanged(m_allowedSuffixes);
 }
 
-QModelIndex PlaylistManager::loadPlaylist(const QList<QUrl> &urls)
-{
-    QModelIndex idx = m_model.loadPlaylist(urls);
-    setProperty("currentIndex", idx.row());
-    return idx;
+// endregion
+
+// region: Playlist Loader and Reset
+
+bool PlaylistManager::loadPlaylist(const QStringList& files) {
+    // Convert string list to url list first
+    QList<QUrl> urls;
+    for (const QString & file : std::as_const(files)) {
+        urls.append(urlFromString(file));
     }
 
-QModelIndex PlaylistManager::loadPlaylist(const QUrl &url)
-{
-    QModelIndex idx = m_model.loadPlaylist(url);
-    setProperty("currentIndex", idx.row());
-    return idx;
+    return loadPlaylist(urls);
 }
 
-QModelIndex PlaylistManager::loadM3U8Playlist(const QUrl &url)
-{
+bool PlaylistManager::loadPlaylist(const QList<QUrl>& urls) {
+    // Check its count, and check M3U8 playlist for single file case.
+    if (urls.isEmpty()) {
+        clearPlaylist();
+        return true;
+    } else if (urls.count() == 1) {
+        const QUrl& firstUrl = urls.first();
+        const QString lowerCaseUrlPath(firstUrl.path().toLower());
+        if (lowerCaseUrlPath.endsWith(".m3u8") || lowerCaseUrlPath.endsWith(".m3u")) {
+            return loadM3U8Playlist(firstUrl);
+        } else {
+            return loadSingleFilePlaylist(firstUrl);
+        }
+    } else {
+        return loadMultipleFilesPlaylist(std::move(urls));
+    }
+}
+
+bool PlaylistManager::loadSingleFilePlaylist(const QUrl& url) {
+    // Check URL at first
+    if (!checkUrl(url))
+        return false;
+
+    // Scout playlist by given file
+    auto scoutResult = PlaylistScout::scout(url, m_allowedSuffixes);
+    if (!scoutResult.has_value()) {
+        return false;
+    }
+
+    // Setup playlist with index
+    setPlaylist(std::move(scoutResult->playlist), scoutResult->indexHint);
+    return true;
+}
+
+bool PlaylistManager::loadMultipleFilesPlaylist(const QList<QUrl>&& urls) {
+    // Check all of them are valid
+    for (const auto& url : std::as_const(urls)) {
+        if (!checkUrl(url)) {
+            return false;
+        }
+    }
+
+    // Set playlist and return
+    setPlaylist(std::move(urls));
+    return true;
+}
+
+bool PlaylistManager::loadM3U8Playlist(const QUrl& url) {
+    // Check URL at first
+    if (!checkUrl(url))
+        return false;
+
+    QList<QUrl> urls;
     QFile file(url.toLocalFile());
     if (file.open(QIODevice::ReadOnly | QIODevice::Text)) {
-        QList<QUrl> urls;
         while (!file.atEnd()) {
             QString line = file.readLine();
             if (line.startsWith('#')) {
@@ -198,86 +111,185 @@ QModelIndex PlaylistManager::loadM3U8Playlist(const QUrl &url)
             }
             QFileInfo fileInfo(file);
             QUrl item = QUrl::fromUserInput(line, fileInfo.absolutePath());
+            if (!checkUrl(item)) {
+                return false;
+            }
             urls.append(item);
         }
-        return loadPlaylist(urls);
     } else {
-        return {};
-    }
+        return false;
     }
 
-int PlaylistManager::totalCount() const
+    setPlaylist(std::move(urls));
+    return true;
+}
+
+void PlaylistManager::setPlaylist(const QList<QUrl>&& urls, std::optional<qsizetype> indexHint) {
+    // Setup playlist
+    m_playlist = std::move(urls);
+
+    // Set index with hint
+    if (indexHint.has_value()) {
+        m_currentIndex = *indexHint;
+    }
+    sanitizeIndex();
+
+    // Raise signal
+    emit playlistChanged(totalCount());
+}
+
+void PlaylistManager::clearPlaylist() {
+    m_playlist.clear();
+    sanitizeIndex();
+    emit playlistChanged(this->totalCount());
+}
+
+// endregion
+
+// region: Playlist Operations
+
+void PlaylistManager::appendToPlaylist(const QString &file)
 {
-    return m_model.rowCount();
+    return appendToPlaylist(urlFromString(file));
 }
 
-QModelIndex PlaylistManager::previousIndex() const
+void PlaylistManager::appendToPlaylist(const QUrl &url)
 {
-    int count = totalCount();
-    if (count == 0) return {};
-
-    return m_model.index(isFirstIndex() ? count - 1 : m_currentIndex - 1);
+    m_playlist.append(url);
+    sanitizeIndex();
+    emit playlistChanged(totalCount());
 }
 
-QModelIndex PlaylistManager::nextIndex() const
+bool PlaylistManager::insertIntoPlaylist(qsizetype index, const QString &file)
 {
-    int count = totalCount();
-    if (count == 0) return {};
-
-    return m_model.index(isLastIndex() ? 0 : m_currentIndex + 1);
+    return insertIntoPlaylist(index, urlFromString(file));
 }
 
-QModelIndex PlaylistManager::curIndex() const
+bool PlaylistManager::insertIntoPlaylist(qsizetype index, const QUrl &url)
 {
-    return m_model.index(m_currentIndex);
+    if (index < 0 || index > totalCount()) {
+        return false;
+    } else {
+        m_playlist.insert(index, url);
+        sanitizeIndex();
+        emit playlistChanged(totalCount());
+        return true;
+    }
+}
+
+bool PlaylistManager::removeFromPlaylist(qsizetype index)
+{
+    if (index < 0 || index >= totalCount()) {
+        return false;
+    } else {
+        m_playlist.removeAt(index);
+        sanitizeIndex();
+        emit playlistChanged(totalCount());
+        return true;
+    }
+}
+
+// endregion
+
+// region: Index Operations
+
+qsizetype PlaylistManager::totalCount() const
+{
+    return m_playlist.count();
+}
+
+std::optional<qsizetype> PlaylistManager::previousIndex() const
+{
+    if (!m_currentIndex.has_value() || totalCount() <= 0) return std::nullopt;
+    return (isFirstIndex() ? totalCount() - 1 : *m_currentIndex - 1);
+}
+
+std::optional<qsizetype> PlaylistManager::nextIndex() const
+{
+    if (!m_currentIndex.has_value() || totalCount() <= 0) return std::nullopt;
+    return (isLastIndex() ? 0 : *m_currentIndex + 1);
 }
 
 bool PlaylistManager::isFirstIndex() const
 {
-    return m_currentIndex == 0;
+    return m_currentIndex.has_value() && *m_currentIndex == 0;
 }
 
 bool PlaylistManager::isLastIndex() const
 {
-    return m_currentIndex + 1 == totalCount();
+    return m_currentIndex.has_value() && *m_currentIndex + 1 == totalCount();
 }
 
-void PlaylistManager::setCurrentIndex(const QModelIndex &index)
+std::optional<qsizetype> PlaylistManager::currentIndex() const
 {
-    if (index.isValid() && index.row() >= 0 && index.row() < totalCount()) {
-        setProperty("currentIndex", index.row());
-    }
+    return m_currentIndex;
 }
 
-QUrl PlaylistManager::urlByIndex(const QModelIndex &index)
+bool PlaylistManager::setCurrentIndex(qsizetype index)
 {
-    return m_model.urlByIndex(index.row());
+    if (!m_currentIndex.has_value()) {
+        return false;
+    }
+    if (index < 0 || index >= totalCount()) {
+        return false;
+    }
+    if (*m_currentIndex == index) {
+        return true;
     }
 
-QString PlaylistManager::localFileByIndex(const QModelIndex &index)
+    m_currentIndex = index;
+    emit currentIndexChanged(index);
+    return true;
+}
+
+QUrl PlaylistManager::urlByIndex(qsizetype index) const
+{
+    return m_playlist.value(index);
+}
+
+QString PlaylistManager::localFileByIndex(qsizetype index) const
 {
     return urlByIndex(index).toLocalFile();
 }
 
-bool PlaylistManager::removeAt(const QModelIndex &index)
-{
-    return m_model.removeAt(index.row());
-}
+// endregion
 
-void PlaylistManager::setAutoLoadFilterSuffixes(const QStringList &nameFilters)
-{
-    m_model.setProperty("autoLoadFilterSuffixes", nameFilters);
-}
+// region: Misc
 
-QList<QUrl> PlaylistManager::convertToUrlList(const QStringList &files)
+void PlaylistManager::sanitizeIndex()
 {
-    QList<QUrl> urlList;
-    for (const QString & str : std::as_const(files)) {
-        QUrl url = QUrl::fromLocalFile(str);
-        if (url.isValid()) {
-            urlList.append(url);
+    auto cnt = totalCount();
+    if (cnt == 0) {
+        // If playlist is empty, current index should be invalid.
+        m_currentIndex = std::nullopt;
+    } else {
+        if (m_currentIndex.has_value()) {
+            // Clamp current index in playlist range.
+            // If it is already in range, not change was done.
+            auto currentIndex = *m_currentIndex;
+            if (currentIndex < 0) {
+                m_currentIndex = 0;
+            } else if (currentIndex >= cnt) {
+                m_currentIndex = cnt - 1;
+            } else {
+                ; // No change.
+            }
+        } else {
+            // If there is no set value for current index,
+            // set it at the beginning of playlist.
+            m_currentIndex = 0;
+        }
     }
 }
 
-    return urlList;
+bool PlaylistManager::checkUrl(const QUrl& url)
+{
+    return url.isValid() && url.isLocalFile();
 }
+
+QUrl PlaylistManager::urlFromString(const QString& file)
+{
+    return QUrl::fromLocalFile(file);
+}
+
+// endregion

app/playlistmanager.h

@@ -5,84 +5,126 @@
 #pragma once
 
 #include <QUrl>
-#include <QAbstractListModel>
-
-class PlaylistModel : public QAbstractListModel
-{
-    Q_OBJECT
-public:
-    enum PlaylistRole {
-        UrlRole = Qt::UserRole
-    };
-    Q_ENUM(PlaylistRole)
-    Q_PROPERTY(QStringList autoLoadFilterSuffixes MEMBER m_autoLoadSuffixes NOTIFY autoLoadFilterSuffixesChanged)
-
-    explicit PlaylistModel(QObject *parent = nullptr);
-    ~PlaylistModel() override;
-
-    void setPlaylist(const QList<QUrl> & urls);
-    QModelIndex loadPlaylist(const QList<QUrl> & urls);
-    QModelIndex loadPlaylist(const QUrl & url);
-    QModelIndex appendToPlaylist(const QUrl & url);
-    bool removeAt(int index);
-    int indexOf(const QUrl & url) const;
-    QUrl urlByIndex(int index) const;
-    QStringList autoLoadFilterSuffixes() const;
-
-    QHash<int, QByteArray> roleNames() const override;
-    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
-    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
-
-signals:
-    void autoLoadFilterSuffixesChanged(QStringList suffixes);
-
-private:
-    // model data
-    QList<QUrl> m_playlist;
-    // properties
-    QStringList m_autoLoadSuffixes = {};
-    // internal
-    QString m_currentDir;
-};
+#include <QObject>
+#include <optional>
 
+/// The manager of playlist.
 class PlaylistManager : public QObject
 {
     Q_OBJECT
 public:
-    Q_PROPERTY(int currentIndex MEMBER m_currentIndex NOTIFY currentIndexChanged)
-    Q_PROPERTY(QStringList autoLoadFilterSuffixes WRITE setAutoLoadFilterSuffixes)
-    Q_PROPERTY(PlaylistModel * model READ model CONSTANT)
-
+    /// Constructs a PlaylistManager with an optional parent QObject.
     explicit PlaylistManager(QObject* parent = nullptr);
+    /// Destructor.
     ~PlaylistManager();
 
-    PlaylistModel * model();
+    /// Get the allowed file suffixes of this playlist.
+    /// @return The current list of allowed suffixes.
+    const QStringList& allowedSuffixes() const;
+    /// Set the allowed file suffixes of this playlist.
+    /// @remark This only works for "load the whole directory by one file" case.
+    /// @param[in] nameFilters The new list of allowed suffixes.
+    void setAllowedSuffixes(const QStringList& nameFilters);
 
-    void setPlaylist(const QList<QUrl> & url);
-    Q_INVOKABLE QModelIndex loadPlaylist(const QList<QUrl> & urls);
-    Q_INVOKABLE QModelIndex loadPlaylist(const QUrl & url);
-    Q_INVOKABLE QModelIndex loadM3U8Playlist(const QUrl & url);
+    /// Load user specified files as playlist.
+    /// @remark The wrapper for another overload.
+    /// @return True for successful load, otherwise false.
+    bool loadPlaylist(const QStringList& files);
+    /// Load user specified URLs as playlist.
+    /// @remark This function automatically dispatch these files into correct sub-load functions.
+    /// @return True for successful load, otherwise false.
+    bool loadPlaylist(const QList<QUrl>& urls);
+    /// Clear the entire playlist and reset current index.
+    void clearPlaylist();
 
-    int totalCount() const;
-    QModelIndex previousIndex() const;
-    QModelIndex nextIndex() const;
-    QModelIndex curIndex() const;
+    /// Append a local file path to the playlist.
+    void appendToPlaylist(const QString& file);
+    /// Append a URL to the playlist.
+    void appendToPlaylist(const QUrl& url);
+    /// Insert a local file path at the given index.
+    /// @return True if inserted successfully, false if index is out of range.
+    bool insertIntoPlaylist(qsizetype index, const QString& file);
+    /// Insert a URL at the given index.
+    /// @return True if inserted successfully, false if index is out of range.
+    bool insertIntoPlaylist(qsizetype index, const QUrl& url);
+    /// Remove the entry at the given index.
+    /// @return True if removed successfully, false if index is out of range.
+    bool removeFromPlaylist(qsizetype index);
+
+    /// Returns the total number of items in the playlist.
+    /// @return Total count of entries in the playlist.
+    qsizetype totalCount() const;
+    /// Try fetching previous index.
+    /// @details This previous index is gallery-loop-aware.
+    /// @return std::nullopt if playlist is empty, otherwise the previous index considering gallery loop.
+    std::optional<qsizetype> previousIndex() const;
+    /// Try fetching next index.
+    /// @details This next index is gallery-loop-aware.
+    /// @return std::nullopt if playlist is empty, otherwise the next index considering gallery loop.
+    std::optional<qsizetype> nextIndex() const;
+    /// Check whether current index is the first index.
+    /// @return False if current index is not the first index or playlist is empty, otherwise true.
     bool isFirstIndex() const;
+    /// Check whether current index is the last index.
+    /// @return False if current index is not the last index or playlist is empty, otherwise true.
     bool isLastIndex() const;
-    void setCurrentIndex(const QModelIndex & index);
-    QUrl urlByIndex(const QModelIndex & index);
-    QString localFileByIndex(const QModelIndex & index);
-    bool removeAt(const QModelIndex & index);
-
-    void setAutoLoadFilterSuffixes(const QStringList &nameFilters);
-
-    static QList<QUrl> convertToUrlList(const QStringList & files);
+    /// Returns the current index.
+    /// @return std::nullopt if the playlist is empty, otherwise the current index.
+    std::optional<qsizetype> currentIndex() const;
+    /// Set the current index.
+    /// @remark Index only can be set when playlist is not empty.
+    /// @return True if successful set, including "not changed" set, otherwise false.
+    /// This return value only indicates whether we can set index and given index is valid for setting.
+    /// If "no changed" set occurs, this function returns true, but doesn't raise current index changed signal.
+    bool setCurrentIndex(qsizetype index);
+    /// Returns the URL at the given index.
+    /// @return The URL if index is valid.
+    /// This class guarantee that this QUrl is pointing to a local file.
+    QUrl urlByIndex(qsizetype index) const;
+    /// Returns the local file path at the given index.
+    /// @return The local file path if index is valid.
+    /// This class guarantee that local file path always is valid.
+    QString localFileByIndex(qsizetype index) const;
 
 signals:
-    void currentIndexChanged(int index);
-    void totalCountChanged(int count);
+    void allowedSuffixesChanged(const QStringList& suffixes);
+    /// Raised when index was changed bu setter.
+    /// The argument holds the new current index.
+    /// Please note that this signal will NOT be raised by the whole playlist change caused index change.
+    void currentIndexChanged(qsizetype index);
+    /// The whole playlist was changed, involving loading, editing and deleting some or full entries.
+    /// The argument holds the total count of new play list.
+    void playlistChanged(qsizetype count);
 
 private:
-    int m_currentIndex = -1;
-    PlaylistModel m_model;
+    /// The fundamental playlist setter.
+    /// @details All playlist load functions will call this function to set playlist at last.
+    /// @param[in] urls ALl urls in this list should be checked by checkUrl() function.
+    /// @param[in] indexHint Try to set current index to this index if possible.
+    void setPlaylist(const QList<QUrl>&& urls, std::optional<qsizetype> indexHint = std::nullopt);
+    /// Load playlist from a single file.
+    /// @details This function scans the same directory for siblings matching allowed suffixes, sorted naturally.
+    /// @return True if the playlist was loaded successfully, false otherwise.
+    bool loadSingleFilePlaylist(const QUrl& url);
+    /// Load playlist from multiple URLs directly.
+    /// @return True if all URLs are valid, false otherwise.
+    bool loadMultipleFilesPlaylist(const QList<QUrl>&& urls);
+    /// Load playlist from an M3U/M3U8 playlist file.
+    /// @return True if loaded successfully, false otherwise.
+    bool loadM3U8Playlist(const QUrl& url);
+
+    /// Make sure that current index is valid.
+    /// @details This function usually is used by those functions manipulating playlist.
+    void sanitizeIndex();
+
+    /// Check whether given QUrl is proper to be put into playlist.
+    /// @details Only the url pointing to local file can be put into playlist.
+    static bool checkUrl(const QUrl& url);
+    /// Convert a string to local file into a QUrl.
+    /// @param[in] file The string pointing to local file.
+    static QUrl urlFromString(const QString& file);
+
+    std::optional<qsizetype> m_currentIndex;
+    QList<QUrl> m_playlist;
+    QStringList m_allowedSuffixes;
 };

app/playlistscout.cpp

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: 2026 yyc12345 <yyc12321@outlook.com>
+//
+// SPDX-License-Identifier: MIT
+
+#include "playlistscout.h"
+
+#include "playlistscouts/qtscout.h"
+#include "playlistscouts/explorerscout.h"
+
+std::optional<PlaylistScout::ScoutResult> PlaylistScout::scout(
+    const QUrl &url, const QStringList &allowedSuffixes) {
+
+#ifdef Q_OS_WIN
+    // In Windows, Qt approach can not aware Windows Explorer custom sort order.
+    // So we need to try using Win32 functions for fetching it at first.
+    if (auto rv = PlaylistScout::Explorer::scout(url, allowedSuffixes); rv.has_value()) {
+        return rv;
+    }
+#endif // Q_OS_WIN
+
+    // TODO: We may add macOS Finder, KDE Dolphin and etc supports in future.
+
+    // Qt way is the last fallback.
+    return PlaylistScout::Qt::scout(url, allowedSuffixes);
+}

app/playlistscout.h

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: 2026 yyc12345 <yyc12321@outlook.com>
+//
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <QUrl>
+#include <QStringList>
+#include <QList>
+#include <optional>
+
+namespace PlaylistScout {
+    /// The result of scout
+    struct ScoutResult {
+        /// The final fetched playlist (it can be empty).
+        /// Each item must be a QUrl pointing to a local file.
+        QList<QUrl> playlist;
+        /// The index of given file located in playlist.
+        /// Nullopt if it is not presented in playlist.
+        std::optional<qsizetype> indexHint;
+    };
+
+    /// @brief Scout available image files in given file's parent dir with given allowed suffixes.
+    /// @param[in] url The path to file whose parent dir is our target dir for finding image files.
+    /// @param[in] allowedSuffixes 
+    /// Each items in this list is a wildcard pattern for matching allowed file name, like \c *.png .
+    /// The fetched item will be preserved if its name matching any of them.
+    /// If this list is empty, there is no restrictions for finding files.
+    /// @return Scout result if success, otherwise nullopt.
+    std::optional<ScoutResult> scout(const QUrl &url, const QStringList &allowedSuffixes);
+}

app/playlistscouts/explorerscout.cpp

@@ -0,0 +1,332 @@
+// SPDX-FileCopyrightText: 2026 yyc12345 <yyc12321@outlook.com>
+//
+// SPDX-License-Identifier: MIT
+
+#include "explorerscout.h"
+
+#ifdef Q_OS_WIN
+
+#include <QDir>
+#include <QDebug>
+#include <QFileInfo>
+#include <QRegularExpression>
+
+#include <optional>
+
+#include <exdisp.h>     // IShellWindows, CLSID_ShellWindows
+#include <servprov.h>   // IServiceProvider
+#include <shlguid.h>    // SID_STopLevelBrowser
+#include <shlobj.h>
+
+// YYC MARK:
+// We use custom RAII wrappers instead of existing COM smart pointers because the
+// project may be built with MinGW, which does not have good compatibility with
+// CComPtr and Microsoft's WRL ComPtr (<wrl/client.h>).
+// Furthermore, PIDLs are not COM objects (they are freed via ILFree, not Release),
+// so no standard smart pointer covers them regardless of compiler.
+
+/// RAII wrapper for COM initialization (CoInitialize / CoUninitialize).
+/// Must be declared before any COM objects (e.g., ComPtr, UniquePidl) so that
+/// CoUninitialize runs after all COM objects are released during scope exit.
+class ComGuard {
+public:
+    ComGuard() : m_hr(CoInitialize(nullptr)) {}
+    ~ComGuard() { if (SUCCEEDED(m_hr)) CoUninitialize(); }
+    ComGuard(const ComGuard&) = delete;
+    ComGuard& operator=(const ComGuard&) = delete;
+
+    bool IsInitialized() const { return SUCCEEDED(m_hr); }
+
+private:
+    HRESULT m_hr;
+};
+
+/// RAII wrapper for COM interface pointers.
+template <typename T>
+class ComPtr {
+public:
+    ComPtr() = default;
+    ComPtr(std::nullptr_t) {}
+    ~ComPtr() { Reset(); }
+    ComPtr(const ComPtr&) = delete;
+    ComPtr& operator=(const ComPtr&) = delete;
+    ComPtr(ComPtr&& other) noexcept : m_ptr(other.m_ptr) { other.m_ptr = nullptr; }
+    ComPtr& operator=(ComPtr&& other) noexcept {
+        if (this != &other) {
+            Reset();
+            m_ptr = other.m_ptr;
+            other.m_ptr = nullptr;
+        }
+        return *this;
+    }
+
+    T* operator->() const { return m_ptr; }
+    T* Get() const { return m_ptr; }
+    T** GetAddressOf() { return &m_ptr; }
+    explicit operator bool() const { return m_ptr != nullptr; }
+    void Reset() { if (m_ptr) { m_ptr->Release(); m_ptr = nullptr; } }
+
+private:
+    T* m_ptr = nullptr;
+};
+
+/// RAII wrapper for PIDL (Item ID List).
+class UniquePidl {
+public:
+    UniquePidl() = default;
+    explicit UniquePidl(LPITEMIDLIST pidl) : m_pidl(pidl) {}
+    ~UniquePidl() { Reset(); }
+    UniquePidl(const UniquePidl&) = delete;
+    UniquePidl& operator=(const UniquePidl&) = delete;
+    UniquePidl(UniquePidl&& other) noexcept : m_pidl(other.m_pidl) { other.m_pidl = nullptr; }
+    UniquePidl& operator=(UniquePidl&& other) noexcept {
+        if (this != &other) {
+            Reset();
+            m_pidl = other.m_pidl;
+            other.m_pidl = nullptr;
+        }
+        return *this;
+    }
+
+    LPCITEMIDLIST Get() const { return m_pidl; }
+    LPITEMIDLIST* GetAddressOf() { return &m_pidl; }
+    explicit operator bool() const { return m_pidl != nullptr; }
+    void Reset() { if (m_pidl) { ILFree(m_pidl); m_pidl = nullptr; } }
+
+private:
+    LPITEMIDLIST m_pidl = nullptr;
+};
+
+/// Outputs a diagnostic warning for debugging Windows Explorer integration failures.
+static void ReportError(const QString& detail)
+{
+    qWarning("Windows Explorer file list fetch error: %s",
+             qPrintable(detail));
+}
+
+/// Normalizes a Windows directory path for case-insensitive comparison:
+/// converts to native separators, lowercases, and ensures a trailing backslash.
+static QString NormalizePath(const QString& path)
+{
+    QString result = QDir::toNativeSeparators(path).toLower();
+    if (!result.endsWith(QChar('\\'))) {
+        result += QChar('\\');
+    }
+    return result;
+}
+
+/// Checks whether the Explorer window represented by the given IDispatch is
+/// displaying the target folder. Returns its IFolderView2 on match, or null.
+static ComPtr<IFolderView2> TryMatchWindow(IDispatch* dispatch, const QString& normalizedTarget)
+{
+    // Navigate: IDispatch -> IServiceProvider -> IShellBrowser.
+    ComPtr<IServiceProvider> serviceProvider;
+    if (FAILED(dispatch->QueryInterface(IID_PPV_ARGS(serviceProvider.GetAddressOf())))) {
+        return nullptr;
+    }
+
+    ComPtr<IShellBrowser> shellBrowser;
+    if (FAILED(serviceProvider->QueryService(SID_STopLevelBrowser,
+            IID_PPV_ARGS(shellBrowser.GetAddressOf())))) {
+        return nullptr;
+    }
+
+    // IShellBrowser -> active IShellView.
+    ComPtr<IShellView> shellView;
+    if (FAILED(shellBrowser->QueryActiveShellView(shellView.GetAddressOf()))) {
+        return nullptr;
+    }
+
+    // Retrieve the folder's path via IPersistIDList.
+    ComPtr<IPersistIDList> persistIdList;
+    if (FAILED(shellView->QueryInterface(IID_PPV_ARGS(persistIdList.GetAddressOf())))) {
+        return nullptr;
+    }
+
+    UniquePidl folderPidl;
+    if (FAILED(persistIdList->GetIDList(folderPidl.GetAddressOf()))) {
+        return nullptr;
+    }
+
+    PWSTR pathStr = nullptr;
+    if (FAILED(SHGetNameFromIDList(folderPidl.Get(), SIGDN_DESKTOPABSOLUTEPARSING, &pathStr))) {
+        return nullptr;
+    }
+
+    QString windowPath = NormalizePath(QString::fromWCharArray(pathStr));
+    CoTaskMemFree(pathStr);
+
+    if (windowPath != normalizedTarget) {
+        return nullptr;
+    }
+
+    // Path matches — query IFolderView2 from the ShellView.
+    ComPtr<IFolderView2> folderView2;
+    if (FAILED(shellView->QueryInterface(IID_PPV_ARGS(folderView2.GetAddressOf())))) {
+        return nullptr;
+    }
+    return folderView2;
+}
+
+/// Tries to find a live Explorer window that is currently displaying the given
+/// folder path. Returns the IFolderView2 from that window, or an empty ComPtr.
+///
+/// Explorer's sort order is stored only in the running Explorer process's memory.
+/// Creating a new shell view via IShellFolder::CreateViewObject yields a default
+/// sort (always by name), so we must find the actual live IFolderView2 instead.
+///
+/// Reference:
+/// - https://www.stephenli.ca/getting-windows-explorers-current-directory-sort-order
+/// - https://github.com/d2phap/ImageGlass/blob/75a296287f338edcf409eee3917531b25ff5d927/v9/Components/ImageGlass.Base/FileSystem/FileFinder.cs
+/// - NuGet Package: D2Phap.EggShell
+static ComPtr<IFolderView2> FindLiveFolderView(const QString& targetFolderPath)
+{
+    // Create the Shell windows collection (all open Explorer windows).
+    ComPtr<IShellWindows> shellWindows;
+    if (FAILED(CoCreateInstance(CLSID_ShellWindows, nullptr, CLSCTX_ALL,
+            IID_PPV_ARGS(shellWindows.GetAddressOf())))) {
+        ReportError("Failed to create IShellWindows instance");
+        return nullptr;
+    }
+
+    QString normalizedTarget = NormalizePath(targetFolderPath);
+
+    // 1. Try the Desktop window first — it may contain the file the user opened.
+    {
+        VARIANT varLoc;
+        VariantInit(&varLoc);
+        varLoc.vt = VT_I4;
+        varLoc.lVal = 0;
+
+        VARIANT varLocRoot;
+        VariantInit(&varLocRoot);
+
+        long desktopHwnd = 0;
+        ComPtr<IDispatch> desktopDispatch;
+        HRESULT findHr = shellWindows->FindWindowSW(
+            &varLoc, &varLocRoot, SWC_DESKTOP,
+            &desktopHwnd, SWFO_NEEDDISPATCH,
+            desktopDispatch.GetAddressOf());
+
+        VariantClear(&varLoc);
+        VariantClear(&varLocRoot);
+
+        if (SUCCEEDED(findHr) && desktopDispatch) {
+            ComPtr<IFolderView2> result = TryMatchWindow(desktopDispatch.Get(), normalizedTarget);
+            if (result) return result;
+        }
+    }
+
+    // 2. Iterate regular Explorer windows.
+    LONG count = 0;
+    shellWindows->get_Count(&count);
+
+    for (LONG i = 0; i < count; i++) {
+        VARIANT varIndex;
+        VariantInit(&varIndex);
+        varIndex.vt = VT_I4;
+        varIndex.lVal = i;
+
+        ComPtr<IDispatch> dispatch;
+        HRESULT itemHr = shellWindows->Item(varIndex, dispatch.GetAddressOf());
+        VariantClear(&varIndex);
+
+        if (FAILED(itemHr) || !dispatch) {
+            continue;
+        }
+
+        ComPtr<IFolderView2> result = TryMatchWindow(dispatch.Get(), normalizedTarget);
+        if (result) return result;
+    }
+
+    return nullptr;
+}
+
+std::optional<PlaylistScout::ScoutResult> PlaylistScout::Explorer::scout(
+    const QUrl &url, const QStringList &allowedSuffixes) {
+    PlaylistScout::ScoutResult rv;
+
+    QFileInfo info(url.toLocalFile());
+    QString folderPath = info.path();
+    QString currentFileName = info.fileName();
+
+    // Pre-compile wildcard suffix filters into regular expressions for performance.
+    QList<QRegularExpression> nameRegexps;
+    for (const QString &pattern : allowedSuffixes) {
+        nameRegexps.append(QRegularExpression(
+            QRegularExpression::wildcardToRegularExpression(pattern),
+            QRegularExpression::CaseInsensitiveOption));
+    }
+
+    // Initialize COM. The ComGuard must be declared before any COM objects
+    // below so that CoUninitialize runs after all of them are released.
+    ComGuard comGuard;
+    if (!comGuard.IsInitialized()) {
+        ReportError("COM initialization failed");
+        return std::nullopt;
+    }
+
+    // Find a live Explorer window that is currently displaying the target folder.
+    ComPtr<IFolderView2> folderView2 = FindLiveFolderView(folderPath);
+    if (!folderView2) {
+        ReportError("No open Explorer window matches the folder: " + folderPath);
+        return std::nullopt;
+    }
+
+    // Get items already sorted in Explorer's view order, as an IShellItemArray.
+    // SVGIO_ALLVIEW returns all items; SVGIO_FLAG_VIEWORDER respects the view's sort.
+    ComPtr<IShellItemArray> itemArray;
+    if (FAILED(folderView2->Items(SVGIO_ALLVIEW | SVGIO_FLAG_VIEWORDER,
+            IID_PPV_ARGS(itemArray.GetAddressOf())))) {
+        ReportError("IFolderView2::Items(SVGIO_ALLVIEW | SVGIO_FLAG_VIEWORDER) failed");
+        return std::nullopt;
+    }
+
+    DWORD itemCount = 0;
+    itemArray->GetCount(&itemCount);
+
+    // Enumerate sorted items, filter by pattern, and build the playlist.
+    for (DWORD i = 0; i < itemCount; i++) {
+        ComPtr<IShellItem> shellItem;
+        if (FAILED(itemArray->GetItemAt(i, shellItem.GetAddressOf()))) {
+            continue;
+        }
+
+        // Get the full parsing path of the item.
+        PWSTR pathStr = nullptr;
+        if (FAILED(shellItem->GetDisplayName(SIGDN_DESKTOPABSOLUTEPARSING, &pathStr)) || !pathStr) {
+            continue;
+        }
+        QString filePath = QString::fromWCharArray(pathStr);
+        CoTaskMemFree(pathStr);
+
+        // Skip directories — the view may include folders alongside files.
+        QFileInfo fileInfo(filePath);
+        if (!fileInfo.isFile()) {
+            continue;
+        }
+
+        QString fileName = fileInfo.fileName();
+
+        // Match against compiled wildcard patterns.
+        bool matches = nameRegexps.isEmpty();
+        for (const QRegularExpression &re : std::as_const(nameRegexps)) {
+            if (re.match(fileName).hasMatch()) {
+                matches = true;
+                break;
+            }
+        }
+        if (!matches) {
+            continue;
+        }
+
+        rv.playlist.append(QUrl::fromLocalFile(filePath));
+        if (fileName == currentFileName) {
+            rv.indexHint = rv.playlist.size() - 1;
+        }
+    }
+
+    return rv;
+}
+
+#endif // Q_OS_WIN

app/playlistscouts/explorerscout.h

@@ -0,0 +1,16 @@
+// SPDX-FileCopyrightText: 2026 yyc12345 <yyc12321@outlook.com>
+//
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include "../playlistscout.h"
+#include <QtSystemDetection>
+
+#ifdef Q_OS_WIN
+
+namespace PlaylistScout::Explorer {
+    std::optional<ScoutResult> scout(const QUrl &url, const QStringList &allowedSuffixes);
+}
+
+#endif // Q_OS_WIN

app/playlistscouts/qtscout.cpp

@@ -0,0 +1,40 @@
+// SPDX-FileCopyrightText: 2025 Gary Wang <git@blumia.net>
+// SPDX-FileCopyrightText: 2026 yyc12345 <yyc12321@outlook.com>
+//
+// SPDX-License-Identifier: MIT
+
+#include "qtscout.h"
+
+#include <QFileInfo>
+#include <QDir>
+#include <QCollator>
+
+std::optional<PlaylistScout::ScoutResult> PlaylistScout::Qt::scout(
+    const QUrl &url, const QStringList &allowedSuffixes) {
+    PlaylistScout::ScoutResult rv;
+
+    QFileInfo info(url.toLocalFile());
+    QDir dir(info.path());
+    QString currentFileName = info.fileName();
+
+    QStringList entryList = dir.entryList(
+        allowedSuffixes, QDir::Files | QDir::NoSymLinks, QDir::NoSort);
+
+    QCollator collator;
+    collator.setNumericMode(true);
+
+    std::sort(entryList.begin(), entryList.end(), collator);
+
+    for (qsizetype i = 0; i < entryList.count(); i++) {
+        const QString &fileName = entryList.at(i);
+        const QString &oneEntry = dir.absoluteFilePath(fileName);
+        const QUrl &url = QUrl::fromLocalFile(oneEntry);
+
+        rv.playlist.append(url);
+        if (fileName == currentFileName) {
+            rv.indexHint = i;
+        }
+    }
+
+    return rv;
+}

app/playlistscouts/qtscout.h

@@ -0,0 +1,11 @@
+// SPDX-FileCopyrightText: 2026 yyc12345 <yyc12321@outlook.com>
+//
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include "../playlistscout.h"
+
+namespace PlaylistScout::Qt {
+    std::optional<ScoutResult> scout(const QUrl &url, const QStringList &allowedSuffixes);
+}

app/settings.cpp

@@ -65,12 +65,6 @@ bool Settings::svgTiny12Only() const
 #endif // QT_VERSION < QT_VERSION_CHECK(6, 9, 3)
 }
 
-Settings::DoubleClickBehavior Settings::doubleClickBehavior() const
-{
-    QString result = m_qsettings->value("double_click_behavior", "").toString();
-    return QEnumHelper::fromString<DoubleClickBehavior>(result, DoubleClickBehavior::Ignore);
-}
-
 Settings::MouseWheelBehavior Settings::mouseWheelBehavior() const
 {
     QString result = m_qsettings->value("mouse_wheel_behavior", "").toString();
@@ -107,12 +101,6 @@ void Settings::setSvgTiny12Only(bool on)
     m_qsettings->sync();
 }
 
-void Settings::setDoubleClickBehavior(DoubleClickBehavior dcb)
-{
-    m_qsettings->setValue("double_click_behavior", QEnumHelper::toString(dcb));
-    m_qsettings->sync();
-}
-
 void Settings::setMouseWheelBehavior(MouseWheelBehavior mwb)
 {
     m_qsettings->setValue("mouse_wheel_behavior", QEnumHelper::toString(mwb));

app/settings.h

@@ -11,23 +11,13 @@ class Settings : public QObject
 {
     Q_OBJECT
 public:
-    enum DoubleClickBehavior {
-        Ignore,
-        Close,
-        Maximize,
-        FullScreen,
-    };
-    Q_ENUM(DoubleClickBehavior)
-
     enum MouseWheelBehavior {
         Zoom,
         Switch,
     };
     Q_ENUM(MouseWheelBehavior)
 
-    // TODO: I want to remove Auto behavior in future.
     enum WindowSizeBehavior {
-        Auto,
         Maximized,
         Windowed,
     };
@@ -38,7 +28,6 @@ public:
     bool useLightCheckerboard() const;
     bool loopGallery() const;
     bool svgTiny12Only() const;
-    DoubleClickBehavior doubleClickBehavior() const;
     MouseWheelBehavior mouseWheelBehavior() const;
     WindowSizeBehavior initWindowSizeBehavior() const;
     Qt::HighDpiScaleFactorRoundingPolicy hiDpiScaleFactorBehavior() const;
@@ -46,7 +35,6 @@ public:
     void setUseLightCheckerboard(bool light);
     void setLoopGallery(bool on);
     void setSvgTiny12Only(bool on);
-    void setDoubleClickBehavior(DoubleClickBehavior dcb);
     void setMouseWheelBehavior(MouseWheelBehavior mwb);
     void setInitWindowSizeBehavior(WindowSizeBehavior wsb);
     void setHiDpiScaleFactorBehavior(Qt::HighDpiScaleFactorRoundingPolicy hidpi);

app/settingsdialog.cpp

@@ -49,15 +49,6 @@ private:
     Pairs pairs;
 };
 
-static EnumComboBoxTransformer<Settings::DoubleClickBehavior> DC_OPTIONS {
-    {
-        {Settings::DoubleClickBehavior::Ignore, QCoreApplication::translate("SettingsDialog", "Do nothing")},
-        {Settings::DoubleClickBehavior::Close, QCoreApplication::translate("SettingsDialog", "Close the window")},
-        {Settings::DoubleClickBehavior::Maximize, QCoreApplication::translate("SettingsDialog", "Toggle maximize")},
-        {Settings::DoubleClickBehavior::FullScreen, QCoreApplication::translate("SettingsDialog", "Toggle fullscreen")}
-    }
-};
-
 static EnumComboBoxTransformer<Settings::MouseWheelBehavior, QString> MW_OPTIONS {
     {
         { Settings::MouseWheelBehavior::Zoom, QCoreApplication::translate("SettingsDialog", "Zoom in and out") },
@@ -67,7 +58,6 @@ static EnumComboBoxTransformer<Settings::MouseWheelBehavior, QString> MW_OPTIONS
 
 static EnumComboBoxTransformer<Settings::WindowSizeBehavior, QString> IWS_OPTIONS {
     {
-        { Settings::WindowSizeBehavior::Auto, QCoreApplication::translate("SettingsDialog", "Auto size") },
         { Settings::WindowSizeBehavior::Maximized, QCoreApplication::translate("SettingsDialog", "Maximized") },
         { Settings::WindowSizeBehavior::Windowed, QCoreApplication::translate("SettingsDialog", "Windowed") }
     }
@@ -83,7 +73,7 @@ static EnumComboBoxTransformer<Qt::HighDpiScaleFactorRoundingPolicy, QString> HI
 };
 
 SettingsDialog::SettingsDialog(QWidget *parent)
-    : QDialog(parent), ui(new Ui::SettingsDialog)
+    : QDialog(parent), ui(new QT_PREPEND_NAMESPACE(Ui::SettingsDialog))
 {
     ui->setupUi(this);
     setWindowFlag(Qt::WindowContextHelpButtonHint, false);
@@ -92,9 +82,6 @@ SettingsDialog::SettingsDialog(QWidget *parent)
     ui->m_useLightCheckerboard->setChecked(settings->useLightCheckerboard());
     ui->m_loopGallery->setChecked(settings->loopGallery());
     ui->m_svgTiny12Only->setChecked(settings->svgTiny12Only());
-    ui->m_doubleClickBehavior->setModel(DC_OPTIONS.buildComboBoxModel(this));
-    Settings::DoubleClickBehavior dcb = settings->doubleClickBehavior();
-    ui->m_doubleClickBehavior->setCurrentIndex(DC_OPTIONS.to_index(dcb));
     ui->m_mouseWheelBehavior->setModel(MW_OPTIONS.buildComboBoxModel(this));
     Settings::MouseWheelBehavior mwb = settings->mouseWheelBehavior();
     ui->m_mouseWheelBehavior->setCurrentIndex(MW_OPTIONS.to_index(mwb));
@@ -125,10 +112,6 @@ SettingsDialog::SettingsDialog(QWidget *parent)
         Settings::instance()->setSvgTiny12Only(state == Qt::Checked);
     });
 
-    connect(ui->m_doubleClickBehavior, QOverload<int>::of(&QComboBox::currentIndexChanged), this, [ = ](int index){
-        Settings::instance()->setDoubleClickBehavior(DC_OPTIONS.to_value(index));
-    });
-
     connect(ui->m_mouseWheelBehavior, QOverload<int>::of(&QComboBox::currentIndexChanged), this, [ = ](int index){
         Settings::instance()->setMouseWheelBehavior(MW_OPTIONS.to_value(index));
     });

app/settingsdialog.ui

@@ -41,43 +41,33 @@
          </widget>
         </item>
        <item row="3" column="0">
-         <widget class="QLabel" name="m_doubleClickBehaviorLabel">
-         <property name="text">
-          <string>Double-click behavior</string>
-         </property>
-        </widget>
-       </item>
-       <item row="3" column="1">
-        <widget class="QComboBox" name="m_doubleClickBehavior"/>
-       </item>
-       <item row="4" column="0">
          <widget class="QLabel" name="m_mouseWheelBehaviorLabel">
          <property name="text">
           <string>Mouse wheel behavior</string>
          </property>
         </widget>
        </item>
-       <item row="4" column="1">
+       <item row="3" column="1">
         <widget class="QComboBox" name="m_mouseWheelBehavior"/>
        </item>
-       <item row="5" column="0">
+       <item row="4" column="0">
          <widget class="QLabel" name="m_initWindowSizeBehaviorLabel">
          <property name="text">
           <string>Default window size</string>
          </property>
         </widget>
        </item>
-       <item row="5" column="1">
+       <item row="4" column="1">
         <widget class="QComboBox" name="m_initWindowSizeBehavior"/>
        </item>
-       <item row="6" column="0">
+       <item row="5" column="0">
          <widget class="QLabel" name="m_hiDpiRoundingPolicyBehaviorLabel">
          <property name="text">
           <string>HiDPI scale factor rounding policy</string>
          </property>
         </widget>
        </item>
-       <item row="6" column="1">
+       <item row="5" column="1">
         <widget class="QComboBox" name="m_hiDpiRoundingPolicyBehavior"/>
        </item>
       </layout>

assets/plain/help.html

@@ -21,4 +21,9 @@
         <br/>
         <span>%9</span>
     </li>
+    <li>
+        <b>%10</b><span>:</span>
+        <br/>
+        <span>%11</span>
+    </li>
 </ul>

assets/plain/translators.html

@@ -1,21 +0,0 @@
-<ul>
-<li><u>Catalan</u>: Toni Estévez</li>
-<li><u>Chinese (Simplified)</u>: Percy Hong</li>
-<li><u>Dutch</u>: Heimen Stoffels</li>
-<li><u>French</u>: J. Lavoie, K. Herbert, Maxime Leroy</li>
-<li><u>German</u>: K. Herbert, J. Lavoie, sal0max</li>
-<li><u>Indonesian</u>: liimee, Reza Almanda</li>
-<li><u>Italian</u>: albanobattistella</li>
-<li><u>Japanese</u>: Black Cat, mmahhi, Percy Hong</li>
-<li><u>Korean</u>: VenusGirl</li>
-<li><u>Norwegian Bokmål</u>: Allan Nordhøy, ovl-1</li>
-<li><u>Punjabi (Pakistan)</u>: bgo-eiu</li>
-<li><u>Russian</u>: Sergey Shornikov, Artem, Andrey</li>
-<li><u>Sinhala</u>: HelaBasa</li>
-<li><u>Slovenian</u>: Andrej Poženel - SDT</li>
-<li><u>Spanish</u>: Toni Estévez, Génesis Toxical, William(ѕ)ⁿ, gallegonovato</li>
-<li><u>Tamil</u>: தமிழ்நேரம் (TamilNeram)</li>
-<li><u>Turkish</u>: E-Akcaer, Oğuz Ersen, Sabri Ünal</li>
-<li><u>Ukrainian</u>: Dan, volkov, Сергій</li>
-<li><u>Vietnamese</u>: Loc Huynh</li>
-</ul>