QWaylandWindow: add QWaylandWindow::setScale

The logic for update window's scale is scattered in multiple places,
we should unify their behavior.

Change-Id: Ic8ba20fdbc44942aed9b4bd0b0b12dad7bee1719
Reviewed-by: Liang Qi <liang.qi@qt.io>

2 files changed, 24 insertions, 23 deletions

diff --git a/src/client/qwaylandwindow.cpp b/src/client/qwaylandwindow.cpp
index 5171a8bb0..9991ade4f 100644
--- a/src/client/qwaylandwindow.cpp
+++ b/src/client/qwaylandwindow.cpp
@@ -107,19 +107,8 @@ void QWaylandWindow::initWindow()
 
         connect(mFractionalScale.data(), &QWaylandFractionalScale::preferredScaleChanged, this, [this](qreal preferredScale) {
             preferredScale = std::max(1.0, preferredScale);
-            if (mScale == preferredScale) {
-                return;
-            }
-            mScale = preferredScale;
-            QWindowSystemInterface::handleWindowDevicePixelRatioChanged(window());
-            ensureSize();
-            if (mViewport)
-                updateViewport();
-            if (isExposed()) {
-                // redraw at the new DPR
-                window()->requestUpdate();
-                sendExposeEvent(QRect(QPoint(), geometry().size()));
-            }
+            Q_ASSERT(mViewport);
+            setScale(preferredScale);
         });
     }
 
@@ -1394,17 +1383,28 @@ void QWaylandWindow::handleScreensChanged()
         return;
 
     int scale = mLastReportedScreen->isPlaceholder() ? 1 : static_cast<QWaylandScreen *>(mLastReportedScreen)->scale();
+    setScale(scale);
+}
 
-    if (scale != mScale) {
-        mScale = scale;
-        QWindowSystemInterface::handleWindowDevicePixelRatioChanged(window());
-        if (mSurface) {
-            if (mViewport)
-                updateViewport();
-            else if (mSurface->version() >= 3)
-                mSurface->set_buffer_scale(std::ceil(mScale));
-        }
-        ensureSize();
+void QWaylandWindow::setScale(qreal newScale)
+{
+    if (qFuzzyCompare(mScale, newScale))
+        return;
+    mScale = newScale;
+
+    QWindowSystemInterface::handleWindowDevicePixelRatioChanged(window());
+    if (mSurface) {
+        if (mViewport)
+            updateViewport();
+        else if (mSurface->version() >= 3)
+            mSurface->set_buffer_scale(std::ceil(mScale));
+    }
+    ensureSize();
+
+    if (isExposed()) {
+        // redraw at the new DPR
+        window()->requestUpdate();
+        sendExposeEvent(QRect(QPoint(), geometry().size()));
     }
 }
 
diff --git a/src/client/qwaylandwindow_p.h b/src/client/qwaylandwindow_p.h
index 445a05b7f..5e064a642 100644
--- a/src/client/qwaylandwindow_p.h
+++ b/src/client/qwaylandwindow_p.h
@@ -346,6 +346,7 @@ private:
 
     void handleMouseEventWithDecoration(QWaylandInputDevice *inputDevice, const QWaylandPointerEvent &e);
     void handleScreensChanged();
+    void setScale(qreal newScale);
     void sendRecursiveExposeEvent();
 
     QWaylandWindow *closestTransientParent() const;