Implement transform/clip support for Android WebView.

content/browser/android/in_process/synchronous_compositor_output_surface.cc

 // Copyright 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/browser/android/in_process/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 136 matching lines @@
 void SynchronousCompositorOutputSurface::SwapBuffers(
     const ui::LatencyInfo& info) {
   context3d()->shallowFlushCHROMIUM();
   did_swap_buffer_ = true;
 }
 
 bool SynchronousCompositorOutputSurface::IsHwReady() {
   return context3d() != NULL;
 }
 
+namespace {
+void AdjustTransformForClip(gfx::Transform* transform, gfx::Rect clip) {
+  // The system-provided transform translates us from the screen origin to the
+  // origin of the clip rect, but CC's draw origin starts at the clip.
+  transform->matrix().postTranslate(-clip.x(), -clip.y(), 0);
+}
+} // namespace
+
 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.
+  AdjustTransformForClip(&transform, clip);
 
-  InvokeComposite(transform, damage_area);
+  surface_size_ = gfx::Size(canvas->getDeviceSize().width(),
+                            canvas->getDeviceSize().height());
+  client_->SetExternalDrawConstraints(transform, clip);
+
+  InvokeComposite(clip.size());
 
   bool finished_draw = current_sw_canvas_ == NULL;
   current_sw_canvas_ = NULL;
   return finished_draw;
 }
 
 bool SynchronousCompositorOutputSurface::DemandDrawHw(
-      gfx::Size view_size,
+      gfx::Size surface_size,
       const gfx::Transform& transform,
-      gfx::Rect damage_area) {
+      gfx::Rect clip) {
   DCHECK(CalledOnValidThread());
   DCHECK(client_);
   DCHECK(context3d());
 
   // Force a GL state restore next time a GLContextVirtual is made current.
   // TODO(boliu): Move this to the end of this function after we have fixed
   // all cases of MakeCurrent calls outside of draws. Tracked in
   // crbug.com/239856.
   gfx::GLContext* current_context = gfx::GLContext::GetCurrent();
   if (current_context)
     current_context->ReleaseCurrent(NULL);
 
   did_swap_buffer_ = false;
 
-  InvokeComposite(transform, damage_area);
+  gfx::Transform adjusted_transform = transform;
+  AdjustTransformForClip(&adjusted_transform, clip);
+  surface_size_ = surface_size;
+  client_->SetExternalDrawConstraints(adjusted_transform, clip);
+  InvokeComposite(clip.size());
 
   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);
+    gfx::Size damage_size) {
+  client_->SetNeedsRedrawRect(gfx::Rect(damage_size));
   if (needs_begin_frame_)
     client_->BeginFrame(base::TimeTicks::Now());
 }
 
 // Not using base::NonThreadSafe as we want to enforce a more exacting threading
 // requirement: SynchronousCompositorOutputSurface() must only be used on the UI
 // thread.
 bool SynchronousCompositorOutputSurface::CalledOnValidThread() const {
   return BrowserThread::CurrentlyOn(BrowserThread::UI);
 }
 
 SynchronousCompositorOutputSurfaceDelegate*
 SynchronousCompositorOutputSurface::GetDelegate() {
   return SynchronousCompositorImpl::FromRoutingID(routing_id_);
 }
 
 }  // namespace content