Fix scrolling flashing in GTK. Fixes bug #12860. r=syd,pavlov a=brendan,chofman

n

widget/src/gtk/nsWindow.cpp

@@ -1020,8 +1020,9 @@ NS_METHOD nsWindow::CreateNative(GtkObject *parentWidget)
 
   // set our background color to make people happy.
 
-  SetBackgroundColor(NS_RGB(192,192,192));
-  //gdk_window_set_back_pixmap(mSuperWin->bin_window, NULL, 0);
+  // SetBackgroundColor(NS_RGB(192,192,192));
+
+  gdk_window_set_back_pixmap(mSuperWin->bin_window, NULL, 0);
 
   // track focus in and focus out events for the shell
   if (mShell) {
@@ -1131,6 +1132,15 @@ NS_IMETHODIMP nsWindow::Scroll(PRInt32 aDx, PRInt32 aDy, nsRect *aClipRect)
 
   if (mSuperWin) {
     gdk_superwin_scroll(mSuperWin, aDx, aDy);
+    // hard process the expose events.  this will force the handling
+    // of the Expose and ConfigureNotify events that we just created
+    // by scrolling the window
+    gdk_superwin_hard_process_exposes(mSuperWin);
+    // sync the update
+    mIsUpdating = PR_FALSE;
+    Update();
+    // flush the event queue to make sure that the draw events get there.
+    XFlush(GDK_DISPLAY());
   }
   return NS_OK;
 }
@@ -2004,6 +2014,7 @@ nsWindow::HandleXlibCrossingEvent(XCrossingEvent * aCrossingEvent)
 void
 nsWindow::HandleXlibConfigureNotifyEvent(XEvent *event)
 {
+#if 0
   XEvent    config_event;
 
   while (XCheckTypedWindowEvent(event->xany.display, 
@@ -2028,7 +2039,9 @@ nsWindow::HandleXlibConfigureNotifyEvent(XEvent *event)
 #endif
   }
 
-  gdk_superwin_clear_translate_queue(mSuperWin, event->xany.serial);
+  // gdk_superwin_clear_translate_queue(mSuperWin, event->xany.serial);
+
+#endif
 
   if (mIsToplevel) {
     nsSizeEvent sevent;

widget/src/gtksuperwin/gdksuperwin.c

@@ -360,3 +360,63 @@ gdk_superwin_clear_translate_queue(GdkSuperWin *superwin, unsigned long serial)
   }
 }
 
+/* This function is generally used after you scroll the window.  It
+ * will hunt through the translation queue for this window and make
+ * sure that all of the Expose and ConfigureNotify events that could
+ * have been part of the translation queue get processed.
+ *
+ * Additionally, it makes sure that any Expose events that are still
+ * in the queue get processed for good measure.  When scrolling this
+ * make it look a lot smoother in Mozilla along the edges. */
+
+void gdk_superwin_hard_process_exposes(GdkSuperWin *superwin)
+{
+  XEvent xevent;
+  
+  GList *tmp_list;
+
+  GdkSuperWinTranslate *translate;
+  
+  // wait for the window event
+  while (superwin->translate_queue)
+  {
+    XWindowEvent(GDK_DISPLAY(),
+                 GDK_WINDOW_XWINDOW(superwin->bin_window),
+                 ( ExposureMask | SubstructureNotifyMask ),
+                 &xevent);
+    switch(xevent.xany.type) {
+    case Expose:
+      tmp_list = superwin->translate_queue;
+      while (tmp_list)
+      {
+        translate = tmp_list->data;
+        xevent.xexpose.x += translate->dx;
+        xevent.xexpose.y += translate->dy;
+        tmp_list = tmp_list->next;
+      }
+      if (superwin->bin_func)
+        superwin->bin_func(superwin, &xevent, superwin->func_data);
+      break;
+    case ConfigureNotify:
+      gdk_superwin_clear_translate_queue(superwin, xevent.xany.serial);
+      break;
+    }
+  }
+  /* try to pull all the exposes out, too. */
+  while (XCheckTypedWindowEvent(GDK_DISPLAY(),
+                                GDK_WINDOW_XWINDOW(superwin->bin_window),
+                                Expose,
+                                &xevent) == True)
+  {
+   tmp_list = superwin->translate_queue;
+   while (tmp_list)
+   {
+     translate = tmp_list->data;
+     xevent.xexpose.x += translate->dx;
+     xevent.xexpose.y += translate->dy;
+     tmp_list = tmp_list->next;
+   }
+   if (superwin->bin_func)
+     superwin->bin_func(superwin, &xevent, superwin->func_data);
+  }
+}

widget/src/gtksuperwin/gdksuperwin.h

@@ -83,6 +83,7 @@ void gdk_superwin_resize (GdkSuperWin *superwin,
 void gdk_superwin_destroy(GdkSuperWin *superwin);
 void gdk_superwin_clear_translate_queue(GdkSuperWin *superwin,
                                         unsigned long serial);
+void gdk_superwin_hard_process_exposes(GdkSuperWin *superwin);
 
 #ifdef __cplusplus
 }