Implement scrolling in QX11GLWindowSurface

Seems to have some artifacts when scrolling by 1 pixel, but apart
from that works pretty well.

Reviewed-By: TrustMe

2 files changed, 36 insertions, 13 deletions

diff --git a/src/opengl/qwindowsurface_x11gl.cpp b/src/opengl/qwindowsurface_x11gl.cpp
index c6897d5..1061008 100644
--- a/src/opengl/qwindowsurface_x11gl.cpp
+++ b/src/opengl/qwindowsurface_x11gl.cpp
@@ -51,14 +51,16 @@
 QT_BEGIN_NAMESPACE
 
 QX11GLWindowSurface::QX11GLWindowSurface(QWidget* window)
-    : QWindowSurface(window), m_GC(0), m_window(window)
+    : QWindowSurface(window), m_windowGC(0), m_pixmapGC(0), m_window(window)
 {
 }
 
 QX11GLWindowSurface::~QX11GLWindowSurface()
 {
-    if (m_GC)
-        XFree(m_GC);
+    if (m_windowGC)
+        XFree(m_windowGC);
+    if (m_pixmapGC)
+        XFree(m_pixmapGC);
 }
 
 QPaintDevice *QX11GLWindowSurface::paintDevice()
@@ -92,13 +94,13 @@ void QX11GLWindowSurface::flush(QWidget *widget, const QRegion &widgetRegion, co
 //         for  (int i = 0; i < num; ++i)
 //             qDebug() << ' ' << i << rects[i].x << rects[i].x << rects[i].y << rects[i].width << rects[i].height;
 
-    if (m_GC == 0) {
-        m_GC = XCreateGC(X11->display, m_window->handle(), 0, 0);
-        XSetGraphicsExposures(X11->display, m_GC, False);
+    if (m_windowGC == 0) {
+        m_windowGC = XCreateGC(X11->display, m_window->handle(), 0, 0);
+        XSetGraphicsExposures(X11->display, m_windowGC, False);
     }
 
-    XSetClipRectangles(X11->display, m_GC, 0, 0, rects, rectCount, YXBanded);
-    XCopyArea(X11->display, m_backBuffer.handle(), m_window->handle(), m_GC,
+    XSetClipRectangles(X11->display, m_windowGC, 0, 0, rects, rectCount, YXBanded);
+    XCopyArea(X11->display, m_backBuffer.handle(), m_window->handle(), m_windowGC,
               boundingRect.x() + offset.x(), boundingRect.y() + offset.y(),
               boundingRect.width(), boundingRect.height(),
               windowBoundingRect.x(), windowBoundingRect.y());
@@ -126,10 +128,30 @@ void QX11GLWindowSurface::setGeometry(const QRect &rect)
 
 bool QX11GLWindowSurface::scroll(const QRegion &area, int dx, int dy)
 {
-    Q_UNUSED(area);
-    Q_UNUSED(dx);
-    Q_UNUSED(dy);
-    return false;
+    if (m_backBuffer.isNull())
+        return false;
+
+    Q_ASSERT(m_backBuffer.data_ptr()->classId() == QPixmapData::X11Class);
+
+    QX11GLPixmapData* pmd = static_cast<QX11GLPixmapData*>(m_backBuffer.data_ptr().data());
+    Q_ASSERT(pmd->context());
+    pmd->context()->makeCurrent();
+    glFinish();
+    eglWaitClient();
+
+    if (!m_pixmapGC)
+        m_pixmapGC = XCreateGC(X11->display, m_backBuffer.handle(), 0, 0);
+
+    foreach (const QRect& rect, area.rects()) {
+        XCopyArea(X11->display, m_backBuffer.handle(), m_backBuffer.handle(), m_pixmapGC,
+                  rect.x(), rect.y(), rect.width(), rect.height(),
+                  rect.x()+dx, rect.y()+dy);
+    }
+
+    XSync(X11->display, False);
+    eglWaitNative(EGL_CORE_NATIVE_ENGINE);
+
+    return true;
 }
 
 /*
diff --git a/src/opengl/qwindowsurface_x11gl_p.h b/src/opengl/qwindowsurface_x11gl_p.h
index 90f3ad5..3a952e8 100644
--- a/src/opengl/qwindowsurface_x11gl_p.h
+++ b/src/opengl/qwindowsurface_x11gl_p.h
@@ -70,7 +70,8 @@ public:
     bool scroll(const QRegion &area, int dx, int dy);
 
 private:
-    GC      m_GC;
+    GC      m_windowGC;
+    GC      m_pixmapGC;
     QPixmap m_backBuffer;
     QWidget *m_window;
 };