Client: Fix incorrect decoration size when QT_SCALE_FACTOR is set

[ChangeLog][QPA plugin] Fixed a bug where window decorations were to small for
for the content when QT_SCALE_FACTOR was set.

Fixes: QTBUG-72993
Change-Id: I1ed26e038c27f7c4454a6bcc04f0849e4af789e7
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

5 files changed, 51 insertions, 28 deletions

diff --git a/src/client/qwaylandabstractdecoration.cpp b/src/client/qwaylandabstractdecoration.cpp
index 32fa6e1b5..0f00b9890 100644
--- a/src/client/qwaylandabstractdecoration.cpp
+++ b/src/client/qwaylandabstractdecoration.cpp
@@ -115,16 +115,17 @@ const QImage &QWaylandAbstractDecoration::contentImage()
 {
     Q_D(QWaylandAbstractDecoration);
     if (d->m_isDirty) {
-        //Update the decoration backingstore
+        // Update the decoration backingstore
 
-        const int scale = waylandWindow()->scale();
-        const QSize imageSize = window()->frameGeometry().size() * scale;
+        const int bufferScale = waylandWindow()->scale();
+        const QSize imageSize = waylandWindow()->surfaceSize() * bufferScale;
         d->m_decorationContentImage = QImage(imageSize, QImage::Format_ARGB32_Premultiplied);
-        d->m_decorationContentImage.setDevicePixelRatio(scale);
+        // Only scale by buffer scale, not QT_SCALE_FACTOR etc.
+        d->m_decorationContentImage.setDevicePixelRatio(bufferScale);
         d->m_decorationContentImage.fill(Qt::transparent);
         this->paint(&d->m_decorationContentImage);
 
-        QRegion damage = marginsRegion(window()->geometry().size(), window()->frameMargins());
+        QRegion damage = marginsRegion(waylandWindow()->surfaceSize(), waylandWindow()->frameMargins());
         for (QRect r : damage)
             waylandWindow()->damage(r);
 
diff --git a/src/client/qwaylandwindow.cpp b/src/client/qwaylandwindow.cpp
index e81221fb5..9e95b3068 100644
--- a/src/client/qwaylandwindow.cpp
+++ b/src/client/qwaylandwindow.cpp
@@ -341,7 +341,7 @@ void QWaylandWindow::setGeometry(const QRect &rect)
         sendExposeEvent(exposeGeometry);
 
     if (mShellSurface)
-        mShellSurface->setWindowGeometry(QRect(QPoint(0, 0), window()->frameGeometry().size()));
+        mShellSurface->setWindowGeometry(windowGeometry());
 }
 
 void QWaylandWindow::resizeFromApplyConfigure(const QSize &sizeWithMargins, const QPoint &offset)
@@ -654,6 +654,23 @@ QMargins QWaylandWindow::frameMargins() const
     return QPlatformWindow::frameMargins();
 }
 
+/*!
+ * Size, with decorations (including including eventual shadows) in wl_surface coordinates
+ */
+QSize QWaylandWindow::surfaceSize() const
+{
+    return geometry().marginsAdded(frameMargins()).size();
+}
+
+/*!
+ * Window geometry as defined by the xdg-shell spec (in wl_surface coordinates)
+ * topLeft is where the shadow stops and the decorations border start.
+ */
+QRect QWaylandWindow::windowGeometry() const
+{
+    return QRect(QPoint(), surfaceSize());
+}
+
 QWaylandShellSurface *QWaylandWindow::shellSurface() const
 {
     return mShellSurface;
@@ -848,9 +865,7 @@ void QWaylandWindow::handleMouse(QWaylandInputDevice *inputDevice, const QWaylan
 
 #if QT_CONFIG(cursor)
     if (e.type == QWaylandPointerEvent::Enter) {
-        QRect windowGeometry = window()->frameGeometry();
-        windowGeometry.moveTopLeft({0, 0}); // convert to wayland surface coordinates
-        QRect contentGeometry = windowGeometry.marginsRemoved(frameMargins());
+        QRect contentGeometry = windowGeometry().marginsRemoved(frameMargins());
         if (contentGeometry.contains(e.local.toPoint()))
             restoreMouseCursor(inputDevice);
     }
diff --git a/src/client/qwaylandwindow_p.h b/src/client/qwaylandwindow_p.h
index 146767a1e..0e573f350 100644
--- a/src/client/qwaylandwindow_p.h
+++ b/src/client/qwaylandwindow_p.h
@@ -125,6 +125,8 @@ public:
     void waitForFrameSync();
 
     QMargins frameMargins() const override;
+    QSize surfaceSize() const;
+    QRect windowGeometry() const;
 
     static QWaylandWindow *fromWlSurface(::wl_surface *surface);
 
diff --git a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
index a8ee9a43a..6455b6fa9 100644
--- a/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
+++ b/src/hardwareintegration/client/wayland-egl/qwaylandglcontext.cpp
@@ -147,9 +147,9 @@ public:
     {
         QOpenGLTextureCache *cache = QOpenGLTextureCache::cacheForContext(m_context->context());
 
-        QRect windowRect = window->window()->frameGeometry();
+        QSize surfaceSize = window->surfaceSize();
         int scale = window->scale() ;
-        glViewport(0, 0, windowRect.width() * scale, windowRect.height() * scale);
+        glViewport(0, 0, surfaceSize.width() * scale, surfaceSize.height() * scale);
 
         glDisable(GL_DEPTH_TEST);
         glDisable(GL_BLEND);
diff --git a/src/plugins/decorations/bradient/main.cpp b/src/plugins/decorations/bradient/main.cpp
index 1bf67bbc3..96ad261b2 100644
--- a/src/plugins/decorations/bradient/main.cpp
+++ b/src/plugins/decorations/bradient/main.cpp
@@ -109,19 +109,22 @@ QWaylandBradientDecoration::QWaylandBradientDecoration()
 
 QRectF QWaylandBradientDecoration::closeButtonRect() const
 {
-    return QRectF(window()->frameGeometry().width() - BUTTON_WIDTH - BUTTON_SPACING * 0 - BUTTONS_RIGHT_MARGIN,
+    const int windowRight = waylandWindow()->windowGeometry().right() + 1;
+    return QRectF(windowRight - BUTTON_WIDTH - BUTTON_SPACING * 0 - BUTTONS_RIGHT_MARGIN,
                   (margins().top() - BUTTON_WIDTH) / 2, BUTTON_WIDTH, BUTTON_WIDTH);
 }
 
 QRectF QWaylandBradientDecoration::maximizeButtonRect() const
 {
-    return QRectF(window()->frameGeometry().width() - BUTTON_WIDTH * 2 - BUTTON_SPACING * 1 - BUTTONS_RIGHT_MARGIN,
+    const int windowRight = waylandWindow()->windowGeometry().right() + 1;
+    return QRectF(windowRight - BUTTON_WIDTH * 2 - BUTTON_SPACING * 1 - BUTTONS_RIGHT_MARGIN,
                   (margins().top() - BUTTON_WIDTH) / 2, BUTTON_WIDTH, BUTTON_WIDTH);
 }
 
 QRectF QWaylandBradientDecoration::minimizeButtonRect() const
 {
-    return QRectF(window()->frameGeometry().width() - BUTTON_WIDTH * 3 - BUTTON_SPACING * 2 - BUTTONS_RIGHT_MARGIN,
+    const int windowRight = waylandWindow()->windowGeometry().right() + 1;
+    return QRectF(windowRight - BUTTON_WIDTH * 3 - BUTTON_SPACING * 2 - BUTTONS_RIGHT_MARGIN,
                   (margins().top() - BUTTON_WIDTH) / 2, BUTTON_WIDTH, BUTTON_WIDTH);
 }
 
@@ -133,13 +136,13 @@ QMargins QWaylandBradientDecoration::margins() const
 void QWaylandBradientDecoration::paint(QPaintDevice *device)
 {
     bool active = window()->handle()->isActive();
-    QRect surfaceRect(QPoint(), window()->frameGeometry().size());
+    QRect wg = waylandWindow()->windowGeometry();
     QRect clips[] =
     {
-        QRect(0, 0, surfaceRect.width(), margins().top()),
-        QRect(0, surfaceRect.height() - margins().bottom(), surfaceRect.width(), margins().bottom()),
-        QRect(0, margins().top(), margins().left(), surfaceRect.height() - margins().top() - margins().bottom()),
-        QRect(surfaceRect.width() - margins().right(), margins().top(), margins().left(), surfaceRect.height() - margins().top() - margins().bottom())
+        QRect(wg.left(), wg.top(), wg.width(), margins().top()),
+        QRect(wg.left(), (wg.bottom() + 1) - margins().bottom(), wg.width(), margins().bottom()),
+        QRect(wg.left(), margins().top(), margins().left(), wg.height() - margins().top() - margins().bottom()),
+        QRect((wg.right() + 1) - margins().right(), wg.top() + margins().top(), margins().right(), wg.height() - margins().top() - margins().bottom())
     };
 
     QRect top = clips[0];
@@ -149,7 +152,7 @@ void QWaylandBradientDecoration::paint(QPaintDevice *device)
 
     // Title bar
     QPainterPath roundedRect;
-    roundedRect.addRoundedRect(surfaceRect, 3, 3);
+    roundedRect.addRoundedRect(wg, 3, 3);
     for (int i = 0; i < 4; ++i) {
         p.save();
         p.setClipRect(clips[i]);
@@ -264,13 +267,14 @@ bool QWaylandBradientDecoration::handleMouse(QWaylandInputDevice *inputDevice, c
     Q_UNUSED(global);
 
     // Figure out what area mouse is in
-    if (local.y() <= margins().top()) {
+    QRect wg = waylandWindow()->windowGeometry();
+    if (local.y() <= wg.top() + margins().top()) {
         processMouseTop(inputDevice,local,b,mods);
-    } else if (local.y() > window()->height() + margins().top()) {
+    } else if (local.y() > wg.bottom() - margins().bottom()) {
         processMouseBottom(inputDevice,local,b,mods);
-    } else if (local.x() <= margins().left()) {
+    } else if (local.x() <= wg.left() + margins().left()) {
         processMouseLeft(inputDevice,local,b,mods);
-    } else if (local.x() > window()->width() + margins().left()) {
+    } else if (local.x() > wg.right() - margins().right()) {
         processMouseRight(inputDevice,local,b,mods);
     } else {
 #if QT_CONFIG(cursor)
@@ -308,15 +312,16 @@ bool QWaylandBradientDecoration::handleTouch(QWaylandInputDevice *inputDevice, c
 
 void QWaylandBradientDecoration::processMouseTop(QWaylandInputDevice *inputDevice, const QPointF &local, Qt::MouseButtons b, Qt::KeyboardModifiers mods)
 {
+    QRect wg = waylandWindow()->windowGeometry();
     Q_UNUSED(mods);
-    if (local.y() <= margins().bottom()) {
+    if (local.y() <= wg.top() + margins().bottom()) {
         if (local.x() <= margins().left()) {
             //top left bit
 #if QT_CONFIG(cursor)
             waylandWindow()->setMouseCursor(inputDevice, Qt::SizeFDiagCursor);
 #endif
             startResize(inputDevice, Qt::TopEdge | Qt::LeftEdge, b);
-        } else if (local.x() > window()->width() + margins().left()) {
+        } else if (local.x() > wg.right() - margins().right()) {
             //top right bit
 #if QT_CONFIG(cursor)
             waylandWindow()->setMouseCursor(inputDevice, Qt::SizeBDiagCursor);
@@ -329,9 +334,9 @@ void QWaylandBradientDecoration::processMouseTop(QWaylandInputDevice *inputDevic
 #endif
             startResize(inputDevice, Qt::TopEdge, b);
         }
-    } else if (local.x() <= margins().left()) {
+    } else if (local.x() <= wg.left() + margins().left()) {
         processMouseLeft(inputDevice, local, b, mods);
-    } else if (local.x() > window()->width() + margins().left()) {
+    } else if (local.x() > wg.right() - margins().right()) {
         processMouseRight(inputDevice, local, b, mods);
     } else if (isRightClicked(b)) {
         showWindowMenu(inputDevice);