Optimized window surfaces on X11 by not setting clip in the common case.

We don't need to set a clip when the flush only contains a single
region. Not setting the clip gives us a slight performance boost.

Reviewed-by: Trond

2 files changed, 13 insertions, 5 deletions

diff --git a/src/gui/painting/qwindowsurface_raster.cpp b/src/gui/painting/qwindowsurface_raster.cpp
index 2f7e879..3a118bd 100644
--- a/src/gui/painting/qwindowsurface_raster.cpp
+++ b/src/gui/painting/qwindowsurface_raster.cpp
@@ -140,7 +140,7 @@ void QRasterWindowSurface::flush(QWidget *widget, const QRegion &rgn, const QPoi
 
     // Not ready for painting yet, bail out. This can happen in
     // QWidget::create_sys()
-    if (!d->image)
+    if (!d->image || rgn.numRects() == 0)
         return;
 
 #ifdef Q_WS_WIN
@@ -203,9 +203,11 @@ void QRasterWindowSurface::flush(QWidget *widget, const QRegion &rgn, const QPoi
         wrgn.translate(-wOffset);
     QRect wbr = wrgn.boundingRect();
 
-    int num;
-    XRectangle *rects = (XRectangle *)qt_getClipRects(wrgn, num);
-    XSetClipRectangles(X11->display, d_ptr->gc, 0, 0, rects, num, YXBanded);
+    if (wrgn.numRects() != 1) {
+        int num;
+        XRectangle *rects = (XRectangle *)qt_getClipRects(wrgn, num);
+        XSetClipRectangles(X11->display, d_ptr->gc, 0, 0, rects, num, YXBanded);
+    }
 
     QRect br = rgn.boundingRect().translated(offset);
 #ifndef QT_NO_MITSHM
@@ -233,6 +235,9 @@ void QRasterWindowSurface::flush(QWidget *widget, const QRegion &rgn, const QPoi
             qt_x11_drawImage(br, wbr.topLeft(), src, widget->handle(), d_ptr->gc, X11->display, (Visual *)widget->x11Info().visual(), widget->x11Info().depth());
         }
     }
+
+    if (wrgn.numRects() != 1)
+        XSetClipMask(X11->display, d_ptr->gc, XNone);
 #endif // FALCON
 
 #ifdef Q_WS_MAC
diff --git a/src/gui/painting/qwindowsurface_x11.cpp b/src/gui/painting/qwindowsurface_x11.cpp
index 5e4433c..46c4c42 100644
--- a/src/gui/painting/qwindowsurface_x11.cpp
+++ b/src/gui/painting/qwindowsurface_x11.cpp
@@ -129,9 +129,12 @@ void QX11WindowSurface::flush(QWidget *widget, const QRegion &rgn, const QPoint
 //         qDebug() << "XSetClipRectangles";
 //         for  (int i = 0; i < num; ++i)
 //             qDebug() << ' ' << i << rects[i].x << rects[i].x << rects[i].y << rects[i].width << rects[i].height;
-    XSetClipRectangles(X11->display, gc, 0, 0, rects, num, YXBanded);
+    if (num != 1)
+        XSetClipRectangles(X11->display, gc, 0, 0, rects, num, YXBanded);
     XCopyArea(X11->display, d_ptr->device.handle(), widget->handle(), gc,
               br.x() + offset.x(), br.y() + offset.y(), br.width(), br.height(), wbr.x(), wbr.y());
+    if (num != 1)
+        XSetClipMask(X11->display, gc, XNone);
 }
 
 void QX11WindowSurface::setGeometry(const QRect &rect)