fix: proper svg icon rendering on hidpi screen.

app/actionmanager.cpp

@@ -6,22 +6,15 @@
 
 #include "mainwindow.h"
 
-#include <QCoreApplication>
+#include <QGuiApplication>
+#include <QSvgRenderer>
+#include <QPainter>
 
 #define ICON_NAME(name)\
-    QStringLiteral(":/icons/" #name "")
+    QStringLiteral(":/icons/" #name ".svg")
 
-#define SETUP_NEW_ACTION(window, action)\
-    action->setObjectName(QString::fromUtf8( #action ));\
-    window->addAction(action);
-
-#define CREATE_NEW_ACTION(window, action)\
-    action = new QAction(window);\
-    SETUP_NEW_ACTION(window, action)
-
-#define CREATE_NEW_ICON_ACTION(window, action, iconname)\
-    action = new QAction(QIcon(ICON_NAME(iconname)), QString(), window);\
-    SETUP_NEW_ACTION(window, action)
+#define ACTION_NAME(s) QStringLiteral(STRIFY(s))
+#define STRIFY(s) #s
 
 ActionManager::ActionManager()
 {
@@ -33,15 +26,36 @@ ActionManager::~ActionManager()
 
 }
 
+QIcon ActionManager::loadHidpiIcon(const QString &resp, QSize sz)
+{
+    QSvgRenderer r(resp);
+    QPixmap pm = QPixmap(sz * qApp->devicePixelRatio());
+    pm.fill(Qt::transparent);
+    QPainter p(&pm);
+    r.render(&p);
+    pm.setDevicePixelRatio(qApp->devicePixelRatio());
+    return QIcon(pm);
+}
+
 void ActionManager::setupAction(MainWindow *mainWindow)
 {
+    auto create_action = [] (QWidget *w, QAction **a, QString i, QString an) {
+        *a = new QAction(w);
+        if (!i.isNull())
+            (*a)->setIcon(ActionManager::loadHidpiIcon(i));
+        (*a)->setObjectName(an);
+        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);
+    #undef CREATE_NEW_ICON_ACTION
 
+    #define CREATE_NEW_ACTION(w, a) create_action(w, &a, QString(), ACTION_NAME(a))
     CREATE_NEW_ACTION(mainWindow, actionPrevPicture);
     CREATE_NEW_ACTION(mainWindow, actionNextPicture);
 
@@ -59,6 +73,7 @@ void ActionManager::setupAction(MainWindow *mainWindow)
     CREATE_NEW_ACTION(mainWindow, actionLocateInFileManager);
     CREATE_NEW_ACTION(mainWindow, actionProperties);
     CREATE_NEW_ACTION(mainWindow, actionQuitApp);
+    #undef CREATE_NEW_ACTION
 
     retranslateUi(mainWindow);
 

app/actionmanager.h

@@ -19,6 +19,8 @@ public:
     void retranslateUi(MainWindow *MainWindow);
     void setupShortcuts();
 
+    static QIcon loadHidpiIcon(const QString &resp, QSize sz = QSize(32, 32));
+
 public:
     QAction *actionOpen;
 

app/bottombuttongroup.cpp

@@ -37,7 +37,7 @@ BottomButtonGroup::BottomButtonGroup(const std::vector<QAction *> &actionList, Q
     auto newActionBtn = [this](QAction * action) -> QToolButton * {
         QToolButton * btn = new QToolButton(this);
         btn->setDefaultAction(action);
-        btn->setIconSize(QSize(40, 40));
+        btn->setIconSize(QSize(32, 32));
         btn->setFixedSize(40, 40);
         return btn;
     };

app/main.cpp

@@ -20,6 +20,9 @@
 int main(int argc, char *argv[])
 {
     QApplication a(argc, argv);
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+    a.setAttribute(Qt::ApplicationAttribute::AA_UseHighDpiPixmaps);
+#endif
 
     QTranslator translator;
     QString qmDir;

app/mainwindow.cpp

@@ -92,20 +92,21 @@ MainWindow::MainWindow(QWidget *parent)
             this, &MainWindow::loadGalleryBySingleLocalFile);
 
     m_closeButton = new ToolButton(true, m_graphicsView);
-    m_closeButton->setIcon(QIcon(":/icons/window-close"));
-    m_closeButton->setIconSize(QSize(50, 50));
+    m_closeButton->setIconSize(QSize(32, 32));
+    m_closeButton->setFixedSize(QSize(50, 50));
+    m_closeButton->setIconResourcePath(":/icons/window-close.svg");
 
     connect(m_closeButton, &QAbstractButton::clicked,
             this, &MainWindow::closeWindow);
 
     m_prevButton = new ToolButton(false, m_graphicsView);
-    m_prevButton->setIcon(QIcon(":/icons/go-previous"));
     m_prevButton->setIconSize(QSize(75, 75));
+    m_prevButton->setIconResourcePath(":/icons/go-previous.svg");
     m_prevButton->setVisible(false);
     m_prevButton->setOpacity(0, false);
     m_nextButton = new ToolButton(false, m_graphicsView);
-    m_nextButton->setIcon(QIcon(":/icons/go-next"));
     m_nextButton->setIconSize(QSize(75, 75));
+    m_nextButton->setIconResourcePath(":/icons/go-next.svg");
     m_nextButton->setVisible(false);
     m_nextButton->setOpacity(0, false);
 

app/toolbutton.cpp

@@ -4,6 +4,7 @@
 
 #include "toolbutton.h"
 
+#include "actionmanager.h"
 #include "opacityhelper.h"
 
 #include <QPainter>
@@ -26,6 +27,11 @@ ToolButton::ToolButton(bool hoverColor, QWidget *parent)
     setStyleSheet(qss);
 }
 
+void ToolButton::setIconResourcePath(const QString &iconp)
+{
+    this->setIcon(ActionManager::loadHidpiIcon(iconp, this->iconSize()));
+}
+
 void ToolButton::setOpacity(qreal opacity, bool animated)
 {
     m_opacityHelper->setOpacity(opacity, animated);

app/toolbutton.h

@@ -13,6 +13,7 @@ class ToolButton : public QPushButton
     Q_OBJECT
 public:
     ToolButton(bool hoverColor = false, QWidget * parent = nullptr);
+    void setIconResourcePath(const QString &iconp);
 
 public slots:
     void setOpacity(qreal opacity, bool animated = true);