Convert the sub-rectangle for GL functions from the views coordinate to the OpenGL coordinate.

content/browser/renderer_host/render_widget_host_view_aura.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 492 matching lines @@
   unsigned char* addr = static_cast<unsigned char*>(
       output->getTopDevice()->accessBitmap(true).getPixels());
   scoped_callback_runner.Release();
   // Wrap the callback with an internal handler so that we can inject our
   // own completion handlers (where we can call AdjustSurfaceProtection).
   base::Callback<void(bool)> wrapper_callback = base::Bind(
       &RenderWidgetHostViewAura::CopyFromCompositingSurfaceFinished,
       AsWeakPtr(),
       callback);
   pending_thumbnail_tasks_.push_back(callback);
-  gfx::Rect src_subrect_in_pixel = ConvertRectToPixel(this, src_subrect);
+
+  // Convert |src_subrect| from the views coordinate (upper-left origin) into
+  // the OpenGL coordinate (lower-left origin).
+  gfx::Rect src_subrect_in_gl = src_subrect;
+  src_subrect_in_gl.set_y(
+      GetViewBounds().height() - src_subrect.y() - src_subrect.height());

[Nico, 2012/07/27 23:41:24]

- src_subrect.bottom() is a bit shorter and does the same thing.


Don't you need to scale by the scale factor here too?

[mazda, 2012/07/28 00:31:44]

Done.

Scaling is done by ConvertRectToPixel below.

+
+  gfx::Rect src_subrect_in_pixel = ConvertRectToPixel(this, src_subrect_in_gl);
   gl_helper->CopyTextureTo(container->texture_id(),
                            container->size(),
                            src_subrect_in_pixel,
                            dst_size_in_pixel,
                            addr,
                            wrapper_callback);
 }
 
 void RenderWidgetHostViewAura::OnAcceleratedCompositingStateChange() {
   // Delay processing the state change until we either get a software frame if
@@ skipping 1118 matching lines @@
     RenderWidgetHost* widget) {
   return new RenderWidgetHostViewAura(widget);
 }
 
 // static
 void RenderWidgetHostViewPort::GetDefaultScreenInfo(WebScreenInfo* results) {
   GetScreenInfoForWindow(results, NULL);
 }
 
 }  // namespace content