Mac: additional repaint fixes related to issue #360.

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@326 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/webwidget_host_mac.mm

@@ -35,13 +35,13 @@ WebWidgetHost* WebWidgetHost::Create(NSView* parent_view,
                                      PaintDelegate* paint_delegate) {
   WebWidgetHost* host = new WebWidgetHost();
 
-  NSRect content_rect = [parent_view bounds];
+  NSRect client_rect = [parent_view bounds];
-  host->view_ = [[NSView alloc] initWithFrame:content_rect];
+  host->view_ = [[NSView alloc] initWithFrame:client_rect];
   [parent_view addSubview:host->view_];
 
   host->webwidget_ = WebPopupMenu::create(client);
-  host->webwidget_->resize(WebSize(content_rect.size.width,
+  host->webwidget_->resize(WebSize(NSWidth(client_rect),
-                                   content_rect.size.height));
+                                   NSHeight(client_rect)));
   return host;
 }
 
@@ -50,19 +50,35 @@ void WebWidgetHost::DidInvalidateRect(const gfx::Rect& damaged_rect) {
   DLOG_IF(WARNING, painting_) << "unexpected invalidation while painting";
 #endif
 
+  const gfx::Rect client_rect(NSRectToCGRect([view_ bounds]));
   paint_rect_ = paint_rect_.Union(damaged_rect);
+  paint_rect_ = paint_rect_.Intersect(client_rect);
 
+  if (!paint_rect_.IsEmpty()) {
     // Convert scroll rectangle to the view's coordinate system.
     NSRect r = NSRectFromCGRect(damaged_rect.ToCGRect());
     r.origin.y = NSHeight([view_ frame]) - NSMaxY(r);
     [view_ setNeedsDisplayInRect:r];
   }
+}
 
 void WebWidgetHost::DidScrollRect(int dx, int dy, const gfx::Rect& clip_rect) {
   DCHECK(dx || dy);
 
   const gfx::Rect client_rect(NSRectToCGRect([view_ bounds]));
-  const gfx::Rect rect = clip_rect.Intersect(client_rect);
+  gfx::Rect rect = clip_rect.Intersect(client_rect);
+
+  // The scrolling rect must not scroll outside the clip rect, because that will
+  // clobber the scrollbars; so the rectangle is shortened a bit from the
+  // leading side of the scroll (could be either horizontally or vertically).
+  if (dx > 0)
+    rect = gfx::Rect(rect.x(), rect.y(), rect.width() - dx, rect.height());
+  else if (dx < 0)
+    rect = gfx::Rect(rect.x() - dx, rect.y(), rect.width() + dx, rect.height());
+  else if (dy > 0)
+    rect = gfx::Rect(rect.x(), rect.y(), rect.width(), rect.height() - dy);
+  else if (dy < 0)
+    rect = gfx::Rect(rect.x(), rect.y() - dy, rect.width(), rect.height() + dy);
 
   // Convert scroll rectangle to the view's coordinate system, and perform the
   // scroll directly, without invalidating the view. In theory this could cause
@@ -73,7 +89,9 @@ void WebWidgetHost::DidScrollRect(int dx, int dy, const gfx::Rect& clip_rect) {
   r.origin.y = NSHeight([view_ bounds]) - NSMaxY(r);
   [view_ scrollRect:r by:NSMakeSize(dx, -dy)];
 
+  const bool can_paint = [view_ lockFocusIfCanDraw];
   const gfx::Rect saved_paint_rect = paint_rect_;
+  gfx::Rect dirty_rect_if_cannot_paint = paint_rect_;
 
   // Repaint the rectangle that was revealed when scrolling the given rectangle.
   // We don't want to invalidate the rectangle, because that would cause the
@@ -89,20 +107,10 @@ void WebWidgetHost::DidScrollRect(int dx, int dy, const gfx::Rect& clip_rect) {
     paint_rect_ = gfx::Rect(rect.x(), rect.y(), rect.width(), dy);
   else if (dy < 0)
     paint_rect_ = gfx::Rect(rect.x(), rect.bottom() + dy, rect.width(), -dy);
-  Paint();
 
-  // Also make sure we repaint the area that the rectangle was pushed over. This
+  paint_rect_ = paint_rect_.Intersect(client_rect);
-  // is required to make sure we don't clobber the scrollbar on that side of the
+  dirty_rect_if_cannot_paint = dirty_rect_if_cannot_paint.Union(paint_rect_);
-  // view. Also do the repaint immediately here, so that we don't get into the
+  if (can_paint && !paint_rect_.IsEmpty())
-  // L-shaped issue described above.
-  if (dx > 0)
-    paint_rect_ = gfx::Rect(rect.right(), rect.y(), dx, rect.height());
-  else if (dx < 0)
-    paint_rect_ = gfx::Rect(rect.x() + dx, rect.y(), -dx, rect.height());
-  else if (dy > 0)
-    paint_rect_ = gfx::Rect(rect.x(), rect.bottom(), rect.width(), dx);
-  else if (dy < 0)
-    paint_rect_ = gfx::Rect(rect.x(), rect.y() + dy, rect.width(), -dx);
     Paint();
 
   // If any part of the scrolled rect was marked as dirty, make sure to redraw
@@ -112,10 +120,18 @@ void WebWidgetHost::DidScrollRect(int dx, int dy, const gfx::Rect& clip_rect) {
   if (!moved_paint_rect.IsEmpty()) {
     moved_paint_rect.Offset(dx, dy);
     paint_rect_ = moved_paint_rect;
+    paint_rect_ = paint_rect_.Intersect(client_rect);
+    dirty_rect_if_cannot_paint = dirty_rect_if_cannot_paint.Union(paint_rect_);
+    if (can_paint && !paint_rect_.IsEmpty())
       Paint();
   }
   
   paint_rect_ = saved_paint_rect;
+
+  if (can_paint)
+    [view_ unlockFocus];
+  else 
+    DidInvalidateRect(dirty_rect_if_cannot_paint);
 }
 
 void WebWidgetHost::ScheduleComposite() {
@@ -207,16 +223,12 @@ void WebWidgetHost::Paint() {
   [NSGraphicsContext restoreGraphicsState];
 
   // Paint to the screen
-  if ([view_ lockFocusIfCanDraw]) {
   NSGraphicsContext* view_context = [NSGraphicsContext currentContext];
-    CGContextRef context =
+  CGContextRef context = static_cast<CGContextRef>([view_context graphicsPort]);
-        static_cast<CGContextRef>([view_context graphicsPort]);
   CGRect bitmap_rect = { { update_rect.x(), update_rect.y() },
                          { update_rect.width(), update_rect.height() } };
   skia::DrawToNativeContext(canvas_.get(), context, update_rect.x(),
       client_rect.height() - update_rect.bottom(), &bitmap_rect);
-    [view_ unlockFocus];
-  }
 }
 
 void WebWidgetHost::SetTooltipText(const CefString& tooltip_text)