From 3d34c9b78ee96b20c5b99358fa574ce057e9ef47 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Samuel=20R=C3=B8dal?= <samuel.rodal@nokia.com>
Date: Thu, 19 May 2011 16:18:21 +0200
Subject: Full translucent background support in xcb and xlib backend.

Make sure to pick an alpha visual also for non-GL surface types, and to
ask for alpha in the window format if the WA_TranslucentBackground
attribute is set.

Reviewed-by: Janusz Lewandowski
(cherry picked from commit 6241e39cff9311c943430ff2f31236b13618f2ac)
---
 src/plugins/platforms/xcb/qxcbwindow.cpp          |  3 ++-
 src/plugins/platforms/xcb/qxcbwindowsurface.cpp   | 11 +++++++++++
 src/plugins/platforms/xlib/qxlibwindow.cpp        |  8 +++++---
 src/plugins/platforms/xlib/qxlibwindowsurface.cpp | 14 +++++++++++++-
 4 files changed, 31 insertions(+), 5 deletions(-)

(limited to 'src/plugins/platforms')

diff --git a/src/plugins/platforms/xcb/qxcbwindow.cpp b/src/plugins/platforms/xcb/qxcbwindow.cpp
index 3365c22c39..0dd29eb8b2 100644
--- a/src/plugins/platforms/xcb/qxcbwindow.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindow.cpp
@@ -113,7 +113,8 @@ QXcbWindow::QXcbWindow(QWidget *tlw)
 
 #if defined(XCB_USE_GLX) || defined(XCB_USE_EGL)
     if (tlw->platformWindowFormat().windowApi() == QPlatformWindowFormat::OpenGL
-        && QApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::OpenGL))
+        && QApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::OpenGL)
+        || tlw->platformWindowFormat().alpha())
     {
 #if defined(XCB_USE_GLX)
         XVisualInfo *visualInfo = qglx_findVisualInfo(DISPLAY_FROM_XCB(m_screen),m_screen->screenNumber(), tlw->platformWindowFormat());
diff --git a/src/plugins/platforms/xcb/qxcbwindowsurface.cpp b/src/plugins/platforms/xcb/qxcbwindowsurface.cpp
index 38c01f9cfd..88a54dc316 100644
--- a/src/plugins/platforms/xcb/qxcbwindowsurface.cpp
+++ b/src/plugins/platforms/xcb/qxcbwindowsurface.cpp
@@ -54,6 +54,7 @@
 #include <stdio.h>
 
 #include <qdebug.h>
+#include <qpainter.h>
 
 class QXcbShmImage : public QXcbObject
 {
@@ -189,6 +190,16 @@ QPaintDevice *QXcbWindowSurface::paintDevice()
 void QXcbWindowSurface::beginPaint(const QRegion &region)
 {
     m_image->preparePaint(region);
+
+    if (m_image->image()->hasAlphaChannel()) {
+        QPainter p(m_image->image());
+        p.setCompositionMode(QPainter::CompositionMode_Source);
+        const QVector<QRect> rects = region.rects();
+        const QColor blank = Qt::transparent;
+        for (QVector<QRect>::const_iterator it = rects.begin(); it != rects.end(); ++it) {
+            p.fillRect(*it, blank);
+        }
+    }
 }
 
 void QXcbWindowSurface::endPaint(const QRegion &)
diff --git a/src/plugins/platforms/xlib/qxlibwindow.cpp b/src/plugins/platforms/xlib/qxlibwindow.cpp
index 4efcb1101c..50ea7b58e4 100644
--- a/src/plugins/platforms/xlib/qxlibwindow.cpp
+++ b/src/plugins/platforms/xlib/qxlibwindow.cpp
@@ -81,9 +81,10 @@ QXlibWindow::QXlibWindow(QWidget *window)
     int w = window->width();
     int h = window->height();
 
-    if(window->platformWindowFormat().windowApi() == QPlatformWindowFormat::OpenGL
-            && QApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::OpenGL) ) {
 #if !defined(QT_NO_OPENGL)
+    if(window->platformWindowFormat().windowApi() == QPlatformWindowFormat::OpenGL
+            && QApplicationPrivate::platformIntegration()->hasCapability(QPlatformIntegration::OpenGL)
+            || window->platformWindowFormat().alpha()) {
 #if !defined(QT_OPENGL_ES_2)
         XVisualInfo *visualInfo = qglx_findVisualInfo(mScreen->display()->nativeDisplay(),mScreen->xScreenNumber(),window->platformWindowFormat());
 #else
@@ -117,8 +118,9 @@ QXlibWindow::QXlibWindow(QWidget *window)
         } else {
             qFatal("no window!");
         }
+    } else
 #endif //!defined(QT_NO_OPENGL)
-    } else {
+    {
         mDepth = mScreen->depth();
         mFormat = (mDepth == 32) ? QImage::Format_ARGB32_Premultiplied : QImage::Format_RGB32;
         mVisual = mScreen->defaultVisual();
diff --git a/src/plugins/platforms/xlib/qxlibwindowsurface.cpp b/src/plugins/platforms/xlib/qxlibwindowsurface.cpp
index 78fe387bb8..a917f452e8 100644
--- a/src/plugins/platforms/xlib/qxlibwindowsurface.cpp
+++ b/src/plugins/platforms/xlib/qxlibwindowsurface.cpp
@@ -49,6 +49,8 @@
 #include "qxlibscreen.h"
 #include "qxlibdisplay.h"
 
+#include "qpainter.h"
+
 # include <sys/ipc.h>
 # include <sys/shm.h>
 # include <X11/extensions/XShm.h>
@@ -108,7 +110,7 @@ void QXlibWindowSurface::resizeShmImage(int width, int height)
 
     Q_ASSERT(shm_attach_status == True);
 
-    shm_img = QImage( (uchar*) image->data, image->width, image->height, image->bytes_per_line, QImage::Format_RGB32 );
+    shm_img = QImage( (uchar*) image->data, image->width, image->height, image->bytes_per_line, win->format() );
 #endif
     painted = false;
 }
@@ -213,6 +215,16 @@ void QXlibWindowSurface::beginPaint(const QRegion &region)
 {
     Q_UNUSED(region);
     resizeBuffer(size());
+
+    if (shm_img.hasAlphaChannel()) {
+        QPainter p(&shm_img);
+        p.setCompositionMode(QPainter::CompositionMode_Source);
+        const QVector<QRect> rects = region.rects();
+        const QColor blank = Qt::transparent;
+        for (QVector<QRect>::const_iterator it = rects.begin(); it != rects.end(); ++it) {
+            p.fillRect(*it, blank);
+        }
+    }
 }
 
 void QXlibWindowSurface::endPaint(const QRegion &region)
-- 
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