xcb: Add experimental legacy support for native X11 painting

This commit revives the old native QPixmap and QPaintEngine
implementations that were present in Qt4. The backing store supports
regular raster windows in this commit. Support for render-to-texture
widgets and OpenGL compositing will be added in a follow-up commit.

Change-Id: I80a9c4f0c42a6f68f571dfee930d95000d5dd950
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 70 insertions, 0 deletions

diff --git a/src/plugins/platforms/xcb/nativepainting/qbackingstore_x11_p.h b/src/plugins/platforms/xcb/nativepainting/qbackingstore_x11_p.h
new file mode 100644
index 0000000000..5f4c24ec11
--- /dev/null
+++ b/src/plugins/platforms/xcb/nativepainting/qbackingstore_x11_p.h
@@ -0,0 +1,70 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QBACKINGSTORE_X11_H
+#define QBACKINGSTORE_X11_H
+
+#include <qpa/qplatformbackingstore.h>
+
+typedef struct _XDisplay Display;
+
+QT_BEGIN_NAMESPACE
+
+class QXcbWindow;
+
+class QXcbNativeBackingStore : public QPlatformBackingStore
+{
+public:
+    QXcbNativeBackingStore(QWindow *window);
+    ~QXcbNativeBackingStore();
+
+    QPaintDevice *paintDevice() override;
+    void flush(QWindow *window, const QRegion &region, const QPoint &offset) override;
+
+    QImage toImage() const override;
+
+    void resize(const QSize &size, const QRegion &staticContents) override;
+    bool scroll(const QRegion &area, int dx, int dy) override;
+
+    void beginPaint(const QRegion &region) override;
+
+private:
+    Display *display() const;
+
+    QPixmap m_pixmap;
+    bool m_translucentBackground;
+};
+
+QT_END_NAMESPACE
+
+#endif // QBACKINGSTORE_X11_H