Implement transform/clip support for Android WebView.

content/renderer/android/synchronous_compositor_output_surface.cc

 // Copyright (c) 2013 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/renderer/android/synchronous_compositor_output_surface.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/time.h"
 #include "cc/output/compositor_frame.h"
@@ skipping 135 matching lines @@
     SynchronousCompositorClient* compositor_client) {
   DCHECK(CalledOnValidThread());
   compositor_client_ = compositor_client;
   UpdateCompositorClientSettings();
 }
 
 bool SynchronousCompositorOutputSurface::IsHwReady() {
   return context3d() != NULL;
 }
 
+static gfx::Transform adjustTransformForClip(gfx::Transform transform,

[joth, 2013/05/25 02:56:40]

nits:

prefer namespace {} to static functions.

capitalize: AdjustTransformForClip()

cont& for transform

maybe comment why we need to remove the clip origin?

+                                             gfx::Rect clip) {
+  transform.matrix().postTranslate(-clip.x(), -clip.y(), 0);
+  return transform;
+}
+
 bool SynchronousCompositorOutputSurface::DemandDrawSw(SkCanvas* canvas) {
   DCHECK(CalledOnValidThread());
   DCHECK(canvas);
   DCHECK(!current_sw_canvas_);
   current_sw_canvas_ = canvas;
 
-  SkRect canvas_clip;
-  gfx::Rect damage_area;
-  if (canvas->getClipBounds(&canvas_clip)) {
-    damage_area = gfx::ToEnclosedRect(gfx::SkRectToRectF(canvas_clip));
-  } else {
-    damage_area = gfx::Rect(kint16max, kint16max);
-  }
+  SkIRect canvas_clip;
+  canvas->getClipDeviceBounds(&canvas_clip);
+  gfx::Rect clip = gfx::SkIRectToRect(canvas_clip);
 
-  gfx::Transform transform;
+  gfx::Transform transform(gfx::Transform::kSkipInitialization);
   transform.matrix() = canvas->getTotalMatrix();  // Converts 3x3 matrix to 4x4.
 
-  InvokeComposite(transform, damage_area);
+  client_->SetDeviceTransformAndClip(adjustTransformForClip(transform, clip),
+                                     clip);
+  InvokeComposite(clip);
 
   bool finished_draw = current_sw_canvas_ == NULL;
   current_sw_canvas_ = NULL;
   return finished_draw;
 }
 
+static gfx::Rect clipFlipY(gfx::Rect clip, gfx::Size view_size) {

[joth, 2013/05/25 02:56:40]

ditto - namespace {} / capitalize

+  clip.set_y(view_size.height() - clip.bottom());
+  return clip;
+}
+
 bool SynchronousCompositorOutputSurface::DemandDrawHw(
       gfx::Size view_size,
       const gfx::Transform& transform,
-      gfx::Rect damage_area) {
+      gfx::Rect clip) {
   DCHECK(CalledOnValidThread());
   DCHECK(client_);
 
   did_swap_buffer_ = false;
 
-  InvokeComposite(transform, damage_area);
+  client_->SetDeviceTransformAndClip(adjustTransformForClip(transform, clip),
+                                     clipFlipY(clip, view_size));

[joth, 2013/05/25 02:56:40]

any idea why we do need to flip Y for clip (in HW mode only) but not for the
SetNeedsRedrawRect() call that follows it?

+  InvokeComposite(clip);
 
   return did_swap_buffer_;
 }
 
 void SynchronousCompositorOutputSurface::InvokeComposite(
-    const gfx::Transform& transform,
     gfx::Rect damage_area) {
-  // TODO(boliu): This assumes |transform| is identity and |damage_area| is the
-  // whole view. Tracking bug to implement this: crbug.com/230463.
-  client_->SetNeedsRedrawRect(damage_area);
+  client_->SetNeedsRedrawRect(gfx::Rect(damage_area.size()));
   if (needs_begin_frame_)
     client_->BeginFrame(base::TimeTicks::Now());
 }
 
 void SynchronousCompositorOutputSurface::UpdateCompositorClientSettings() {
   if (compositor_client_) {
     compositor_client_->SetContinuousInvalidate(needs_begin_frame_);
   }
 }
 
 // Not using base::NonThreadSafe as we want to enforce a more exacting threading
 // requirement: SynchronousCompositorOutputSurface() must only be used by
 // embedders that supply their own compositor loop via
 // OverrideCompositorMessageLoop().
 bool SynchronousCompositorOutputSurface::CalledOnValidThread() const {
   return base::MessageLoop::current() && (base::MessageLoop::current() ==
       GetContentClient()->renderer()->OverrideCompositorMessageLoop());
 }
 
 }  // namespace content