refactor(FramelessWindow): use Qt API for window resizing (#81)

No longer use Win32API for window resizing. This should work under all platforms that support window resizing.

app/framelesswindow.cpp

@@ -1,33 +1,33 @@
 // 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>
-#ifdef _WIN32
-#include <windows.h>
-#endif // _WIN32
 
 FramelessWindow::FramelessWindow(QWidget *parent)
     : QWidget(parent)
     , m_centralLayout(new QVBoxLayout(this))
+    , m_oldCursorShape(Qt::ArrowCursor)
+    , m_oldEdges()
 {
 #if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
-    // The Qt::WindowMinMaxButtonsHint or Qt::WindowMinimizeButtonHint here is to
+    this->setWindowFlags(Qt::Window | Qt::FramelessWindowHint | Qt::WindowMinMaxButtonsHint);
-    // provide the ability to use Winkey + Up/Down to toggle minimize/maximize.
-    // But a bug introduced in Qt6 that this flag will break the WM_NCHITTEST event.
-    // See: QTBUG-112356 and discussion in https://github.com/BLumia/pineapple-pictures/pull/81
-    // Thanks @yyc12345 for finding out the source of the issue.
-    this->setWindowFlags(Qt::Window | Qt::FramelessWindowHint);
 #else
     // There is a bug in Qt 5 that will make pressing Meta+Up cause the app
     // fullscreen under Windows, see QTBUG-91226 to learn more.
     // The bug seems no longer exists in Qt 6 (I only tested it under Qt 6.3.0).
     this->setWindowFlags(Qt::Window | Qt::FramelessWindowHint | Qt::WindowMinimizeButtonHint);
 #endif // QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    this->setMouseTracking(true);
+    this->setAttribute(Qt::WA_Hover, true);
+    this->installEventFilter(this);
 
     m_centralLayout->setContentsMargins(QMargins());
 }
@@ -43,89 +43,103 @@ void FramelessWindow::setCentralWidget(QWidget *widget)
     m_centralWidget = widget;
 }
 
-bool FramelessWindow::nativeEvent(const QByteArray &eventType, void *message, NATIVE_RESULT *result)
+void FramelessWindow::installResizeCapture(QObject* widget)
 {
-#ifdef _WIN32
+    widget->installEventFilter(this);
-    // https://stackoverflow.com/questions/43505580/qt-windows-resizable-frameless-window
-    // Too lazy to do this now.. just stackoverflow it and did a copy and paste..
-    Q_UNUSED(eventType)
-    MSG* msg = static_cast<MSG*>(message);
-
-    if (msg->message == WM_NCHITTEST) {
-        if (isMaximized()) {
-            return false;
-        }
-
-        *result = 0;
-        const LONG borderWidth = 8;
-        RECT winrect;
-        GetWindowRect(reinterpret_cast<HWND>(winId()), &winrect);
-
-        // must be short to correctly work with multiple monitors (negative coordinates)
-        short x = msg->lParam & 0x0000FFFF;
-        short y = (msg->lParam & 0xFFFF0000) >> 16;
-
-        bool resizeWidth = minimumWidth() != maximumWidth();
-        bool resizeHeight = minimumHeight() != maximumHeight();
-        if (resizeWidth) {
-            //left border
-            if (x >= winrect.left && x < winrect.left + borderWidth) {
-                *result = HTLEFT;
-            }
-            //right border
-            if (x < winrect.right && x >= winrect.right - borderWidth) {
-                *result = HTRIGHT;
-            }
-        }
-        if (resizeHeight) {
-            //bottom border
-            if (y < winrect.bottom && y >= winrect.bottom - borderWidth) {
-                *result = HTBOTTOM;
-            }
-            //top border
-            if (y >= winrect.top && y < winrect.top + borderWidth) {
-                *result = HTTOP;
-            }
-        }
-        if (resizeWidth && resizeHeight) {
-            //bottom left corner
-            if (x >= winrect.left && x < winrect.left + borderWidth &&
-                    y < winrect.bottom && y >= winrect.bottom - borderWidth)
-            {
-                *result = HTBOTTOMLEFT;
-            }
-            //bottom right corner
-            if (x < winrect.right && x >= winrect.right - borderWidth &&
-                    y < winrect.bottom && y >= winrect.bottom - borderWidth)
-            {
-                *result = HTBOTTOMRIGHT;
-            }
-            //top left corner
-            if (x >= winrect.left && x < winrect.left + borderWidth &&
-                    y >= winrect.top && y < winrect.top + borderWidth)
-            {
-                *result = HTTOPLEFT;
-            }
-            //top right corner
-            if (x < winrect.right && x >= winrect.right - borderWidth &&
-                    y >= winrect.top && y < winrect.top + borderWidth)
-            {
-                *result = HTTOPRIGHT;
-            }
-        }
-
-        if (*result != 0)
-            return true;
-
-        QWidget *action = QApplication::widgetAt(QCursor::pos());
-        if (action == this) {
-            *result = HTCAPTION;
-            return true;
-        }
-    }
-
-    return false;
-#else
-    return QWidget::nativeEvent(eventType, message, result);
-#endif // _WIN32
 }
+
+bool FramelessWindow::eventFilter(QObject* o, QEvent* e)
+{
+    switch (e->type()) {
+    case QEvent::HoverMove:
+    {
+        QWidget* wg = qobject_cast<QWidget*>(o);
+        if (wg != nullptr)
+            return mouseHover(static_cast<QHoverEvent*>(e), wg);
+
+        break;
+    }
+    case QEvent::MouseButtonPress:
+        return mousePress(static_cast<QMouseEvent*>(e));
+    }
+
+    return QWidget::eventFilter(o, e);
+}
+
+bool FramelessWindow::mouseHover(QHoverEvent* event, QWidget* wg)
+{
+    QWindow* win = window()->windowHandle();
+    Qt::Edges edges = this->getEdgesByPos(wg->mapToGlobal(event->oldPos()), win->frameGeometry());
+
+    // backup & restore cursor shape
+    if (edges && !m_oldEdges)
+        // entering the edge. backup cursor shape
+        m_oldCursorShape = win->cursor().shape();
+    if (!edges && m_oldEdges)
+        // leaving the edge. restore cursor shape
+        win->setCursor(m_oldCursorShape);
+
+    // save the latest edges status
+    m_oldEdges = edges;
+
+    // show resize cursor shape if cursor is within border
+    if (edges) {
+        win->setCursor(this->getCursorByEdge(edges, Qt::ArrowCursor));
+        return true;
+    }
+
+    return false;
+}
+
+bool FramelessWindow::mousePress(QMouseEvent* event)
+{
+    if (event->buttons() & Qt::LeftButton && !isMaximized()) {
+        QWindow* win = window()->windowHandle();
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+        Qt::Edges edges = this->getEdgesByPos(event->globalPosition().toPoint(), win->frameGeometry());
+#else
+        Qt::Edges edges = this->getEdgesByPos(event->globalPos(), win->frameGeometry());
+#endif // QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+        if (edges) {
+            win->startSystemResize(edges);
+            return true;
+        }
+    }
+
+    return false;
+}
+
+Qt::CursorShape FramelessWindow::getCursorByEdge(const Qt::Edges& edges, Qt::CursorShape default_cursor)
+{
+    if ((edges == (Qt::TopEdge | Qt::LeftEdge)) || (edges == (Qt::RightEdge | Qt::BottomEdge)))
+        return Qt::SizeFDiagCursor;
+    else if ((edges == (Qt::TopEdge | Qt::RightEdge)) || (edges == (Qt::LeftEdge | Qt::BottomEdge)))
+        return Qt::SizeBDiagCursor;
+    else if (edges & (Qt::TopEdge | Qt::BottomEdge))
+        return Qt::SizeVerCursor;
+    else if (edges & (Qt::LeftEdge | Qt::RightEdge))
+        return Qt::SizeHorCursor;
+    else
+        return default_cursor;
+}
+
+Qt::Edges FramelessWindow::getEdgesByPos(const QPoint gpos, const QRect& winrect)
+{
+    const int borderWidth = 8;
+    Qt::Edges edges;
+
+    int x = gpos.x() - winrect.x();
+    int y = gpos.y() - winrect.y();
+
+    if (x < borderWidth)
+        edges |= Qt::LeftEdge;
+    if (x > (winrect.width() - borderWidth))
+        edges |= Qt::RightEdge;
+    if (y < borderWidth)
+        edges |= Qt::TopEdge;
+    if (y > (winrect.height() - borderWidth))
+        edges |= Qt::BottomEdge;
+
+    return edges;
+}
+

app/framelesswindow.h

@@ -7,12 +7,6 @@
 
 #include <QWidget>
 
-#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
-    typedef qintptr NATIVE_RESULT;
-#else
-    typedef long NATIVE_RESULT;
-#endif // QT_VERSION_CHECK(6, 0, 0)
-
 QT_BEGIN_NAMESPACE
 class QVBoxLayout;
 QT_END_NAMESPACE
@@ -24,11 +18,20 @@ public:
     explicit FramelessWindow(QWidget *parent = nullptr);
 
     void setCentralWidget(QWidget * widget);
+    void installResizeCapture(QObject* widget);
 
 protected:
-    bool nativeEvent(const QByteArray& eventType, void* message, NATIVE_RESULT* result) override;
+    bool eventFilter(QObject *o, QEvent *e) override;
+    bool mouseHover(QHoverEvent* event, QWidget* wg);
+    bool mousePress(QMouseEvent* event);
 
 private:
+    Qt::Edges m_oldEdges;
+    Qt::CursorShape m_oldCursorShape;
+
+    Qt::CursorShape getCursorByEdge(const Qt::Edges& edges, Qt::CursorShape default_cursor);
+    Qt::Edges getEdgesByPos(const QPoint pos, const QRect& winrect);
+
     QVBoxLayout * m_centralLayout = nullptr;
     QWidget * m_centralWidget = nullptr; // just a pointer, doesn't take the ownership.
 };

app/mainwindow.cpp

@@ -162,6 +162,13 @@ MainWindow::MainWindow(QWidget *parent)
     QTimer::singleShot(0, this, [this](){
         m_am->setupShortcuts();
     });
+
+    // allow some mouse events can go through these widgets for resizing window.
+    installResizeCapture(m_closeButton);
+    installResizeCapture(m_graphicsView);
+    installResizeCapture(m_graphicsView->viewport());
+    installResizeCapture(m_gv);
+    installResizeCapture(m_gv->viewport());
 }
 
 MainWindow::~MainWindow()