Examples: remove OpenGL code paths from painting examples

The extra code for using the OpenGL paint engine is significant enough
to be distracting from what the examples are supposed to show. If we
want to show how to use QPainter on an OpenGL widget, then we can make
dedicated and documented examples for that, in the OpenGL category. And
we have such examples in the Qt OpenGL module anyway.

As is, the examples feel more like manual tests of the OpenGL paint
engine; if we need more coverage there, then we can add it there.

Change-Id: I7b56ea6d08c02cd0a1050ab03991656a0538498d
Reviewed-by: Laszlo Agocs <[email protected]>
Reviewed-by: Qt CI Bot <[email protected]>
Reviewed-by: Eirik Aavitsland <[email protected]>

1 files changed, 2 insertions, 78 deletions

diff --git a/examples/widgets/painting/shared/arthurwidgets.cpp b/examples/widgets/painting/shared/arthurwidgets.cpp
index 7f3e50f5e6e..4ff435783b2 100644
--- a/examples/widgets/painting/shared/arthurwidgets.cpp
+++ b/examples/widgets/painting/shared/arthurwidgets.cpp
@@ -14,11 +14,6 @@
 #include <QBoxLayout>
 #include <QRegularExpression>
 #include <QOffscreenSurface>
-#include <QOpenGLContext>
-#if QT_CONFIG(opengl)
-#include <QtOpenGL/QOpenGLPaintDevice>
-#include <QtOpenGL/QOpenGLWindow>
-#endif
 
 extern QPixmap cached(const QString &img);
 
@@ -34,61 +29,13 @@ ArthurFrame::ArthurFrame(QWidget *parent)
     pt.end();
 }
 
-
-#if QT_CONFIG(opengl)
-void ArthurFrame::enableOpenGL(bool use_opengl)
-{
-    if (m_use_opengl == use_opengl)
-        return;
-
-    m_use_opengl = use_opengl;
-
-    if (!m_glWindow && use_opengl) {
-        createGlWindow();
-        QApplication::postEvent(this, new QResizeEvent(size(), size()));
-    }
-
-    if (use_opengl) {
-        m_glWidget->show();
-    } else {
-        if (m_glWidget)
-            m_glWidget->hide();
-    }
-
-    update();
-}
-
-void ArthurFrame::createGlWindow()
-{
-    Q_ASSERT(m_use_opengl);
-
-    m_glWindow = new QOpenGLWindow();
-    QSurfaceFormat f = QSurfaceFormat::defaultFormat();
-    f.setSamples(4);
-    f.setAlphaBufferSize(8);
-    f.setStencilBufferSize(8);
-    m_glWindow->setFormat(f);
-    m_glWindow->setFlags(Qt::WindowTransparentForInput);
-    m_glWindow->resize(width(), height());
-    m_glWidget = QWidget::createWindowContainer(m_glWindow, this);
-    // create() must be called after createWindowContainer() otherwise
-    // an incorrect offsetting of the position will occur.
-    m_glWindow->create();
-}
-#endif
-
-
 void ArthurFrame::paintEvent(QPaintEvent *e)
 {
     static QImage *static_image = nullptr;
 
     QPainter painter;
 
-    if (preferImage()
-#if QT_CONFIG(opengl)
-        && !m_use_opengl
-#endif
-        ) {
+    if (preferImage()) {
         if (!static_image || static_image->size() != size()) {
             delete static_image;
             static_image = new QImage(size(), QImage::Format_RGB32);
@@ -103,18 +50,7 @@ void ArthurFrame::paintEvent(QPaintEvent *e)
         painter.fillRect(0, height() - o, o, o, bg);
         painter.fillRect(width() - o, height() - o, o, o, bg);
     } else {
-#if QT_CONFIG(opengl)
-        if (m_use_opengl && m_glWindow->isValid()) {
-            m_glWindow->makeCurrent();
-
-            painter.begin(m_glWindow);
-            painter.fillRect(QRectF(0, 0, m_glWindow->width(), m_glWindow->height()), palette().color(backgroundRole()));
-        } else {
-            painter.begin(this);
-        }
-#else
         painter.begin(this);
-#endif
     }
 
     painter.setClipRect(e->rect());
@@ -158,27 +94,15 @@ void ArthurFrame::paintEvent(QPaintEvent *e)
     painter.setBrush(Qt::NoBrush);
     painter.drawPath(clipPath);
 
-    if (preferImage()
-#if QT_CONFIG(opengl)
-        && !m_use_opengl
-#endif
-        ) {
+    if (preferImage()) {
         painter.end();
         painter.begin(this);
         painter.drawImage(e->rect(), *static_image, e->rect());
     }
-#if QT_CONFIG(opengl)
-    if (m_use_opengl)
-        m_glWindow->update();
-#endif
 }
 
 void ArthurFrame::resizeEvent(QResizeEvent *e)
 {
-#if QT_CONFIG(opengl)
-    if (m_glWidget)
-        m_glWidget->setGeometry(0, 0, e->size().width(), e->size().height());
-#endif
     QWidget::resizeEvent(e);
 }