Fix up flawed TranslucentBackground usage in docs and examples

Following the qtbase fixes, start doing things correctly in the
QQuickWidget examples too. Remove the checkbox and use a --transparent
command line argument (like in hellogl2).

In addition --transparent --no_render_alpha can be used to verify the
most problematic case: when alpha is present and the backingstore contains
semi-transparent pixels in places where the underlying QOpenGLWidget is
opaque. Here the result must still be an opaque pixel. This was previously
ensured by a glColorMask call, now replaced by glBlendFuncSeparate in
QPlatformBackingStore.

Task-number: QTBUG-47276
Change-Id: Ia040f899405f73e95e957becee5df43683af9c39
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@theqtcompany.com>
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

1 files changed, 1 insertions, 4 deletions

diff --git a/examples/quick/quickwidgets/qquickviewcomparison/mainwindow.h b/examples/quick/quickwidgets/qquickviewcomparison/mainwindow.h
index c58523f675..5b86c93f38 100644
--- a/examples/quick/quickwidgets/qquickviewcomparison/mainwindow.h
+++ b/examples/quick/quickwidgets/qquickviewcomparison/mainwindow.h
@@ -53,7 +53,7 @@ QT_FORWARD_DECLARE_CLASS(QLayout)
 class MainWindow : public QWidget
 {
 public:
-    MainWindow();
+    MainWindow(bool transparency);
 
 protected:
     void resizeEvent(QResizeEvent*);
@@ -63,7 +63,6 @@ private slots:
     void onStatusChangedView(QQuickView::Status status);
     void onStatusChangedWidget(QQuickWidget::Status status);
     void onSceneGraphError(QQuickWindow::SceneGraphError error, const QString &message);
-    void onTransparentChanged(bool enabled);
 
 private:
     void switchTo(QWidget *view);
@@ -86,8 +85,6 @@ private:
 
     QSurfaceFormat m_format;
 
-    QCheckBox *m_checkboxTransparent;
-
     bool m_transparent;
 };