Test that pixels are drawn to the screen

No-oped on Windows and use_webkit_compositor==1.

BUG=None
TEST=compositor_unittests --gtest_filter=LayerWithRealCompositorTest.DrawPixels


Review URL: http://codereview.chromium.org/8418036

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@108427 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 90 insertions, 0 deletions

diff --git a/ui/gfx/compositor/compositor.h b/ui/gfx/compositor/compositor.h
index 6096d0a..9343975 100644
--- a/ui/gfx/compositor/compositor.h
+++ b/ui/gfx/compositor/compositor.h
@@ -13,6 +13,7 @@
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/size.h"
 
+class SkBitmap;
 class SkCanvas;
 namespace gfx {
 class Point;
@@ -127,6 +128,9 @@ class COMPOSITOR_EXPORT Compositor : public base::RefCounted<Compositor> {
   // compositing.
   void Draw(bool force_clear);
 
+  // Reads the contents of the last rendered frame into the given bitmap.
+  virtual void ReadPixels(SkBitmap* bitmap) = 0;
+
   // Notifies the compositor that the size of the widget that it is
   // drawing to has changed.
   void WidgetSizeChanged(const gfx::Size& size) {
diff --git a/ui/gfx/compositor/compositor_cc.cc b/ui/gfx/compositor/compositor_cc.cc
index 754b6a8..780007c 100644
--- a/ui/gfx/compositor/compositor_cc.cc
+++ b/ui/gfx/compositor/compositor_cc.cc
@@ -174,6 +174,10 @@ void CompositorCC::DrawTree() {
   host_.composite();
 }
 
+void CompositorCC::ReadPixels(SkBitmap* bitmap) {
+  NOTIMPLEMENTED();
+}
+
 void CompositorCC::animateAndLayout(double frameBeginTime) {
 }
 
diff --git a/ui/gfx/compositor/compositor_cc.h b/ui/gfx/compositor/compositor_cc.h
index 1bd4b58..dcaba1e 100644
--- a/ui/gfx/compositor/compositor_cc.h
+++ b/ui/gfx/compositor/compositor_cc.h
@@ -95,6 +95,7 @@ class COMPOSITOR_EXPORT CompositorCC : public Compositor,
   virtual void OnWidgetSizeChanged() OVERRIDE;
   virtual void OnRootLayerChanged() OVERRIDE;
   virtual void DrawTree() OVERRIDE;
+  virtual void ReadPixels(SkBitmap* bitmap) OVERRIDE;
 
   // WebLayerTreeViewClient implementation.
   virtual void animateAndLayout(double frameBeginTime) OVERRIDE;
diff --git a/ui/gfx/compositor/compositor_gl.cc b/ui/gfx/compositor/compositor_gl.cc
index c28195c..92ada06 100644
--- a/ui/gfx/compositor/compositor_gl.cc
+++ b/ui/gfx/compositor/compositor_gl.cc
@@ -11,6 +11,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/singleton.h"
 #include "base/threading/thread_restrictions.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkDevice.h"
 #include "third_party/skia/include/core/SkMatrix.h"
 #include "third_party/skia/include/core/SkPoint.h"
@@ -505,6 +506,53 @@ CompositorGL::~CompositorGL() {
   gl_context_ = NULL;
 }
 
+void CompositorGL::ReadPixels(SkBitmap* bitmap) {
+  MakeCurrent();
+
+  bitmap->setConfig(SkBitmap::kARGB_8888_Config,
+                    size().width(),
+                    size().height());
+  bitmap->allocPixels();
+  SkAutoLockPixels lock(*bitmap);
+  unsigned char* pixels = static_cast<unsigned char*>(bitmap->getPixels());
+
+  // Check that it's a tight pixel packing
+  DCHECK_EQ(bitmap->rowBytes(),
+            SkBitmap::ComputeRowBytes(bitmap->config(), bitmap->width()));
+
+  GLint current_alignment = 0;
+  glGetIntegerv(GL_PACK_ALIGNMENT, &current_alignment);
+  glPixelStorei(GL_PACK_ALIGNMENT, 4);
+  glReadPixels(0,
+               0,
+               size().width(),
+               size().height(),
+               GL_RGBA,
+               GL_UNSIGNED_BYTE,
+               pixels);
+  glPixelStorei(GL_PACK_ALIGNMENT, current_alignment);
+
+  // Swizzle from RGBA to BGRA
+  size_t bitmap_size = 4 * size().width() * size().height();
+  for(size_t i = 0; i < bitmap_size; i += 4)
+    std::swap(pixels[i], pixels[i + 2]);
+
+  // Vertical flip to transform from GL co-ords
+  size_t row_size = 4 * size().width();
+  scoped_array<unsigned char> tmp_row(new unsigned char[row_size]);
+  for(int row = 0; row < size().height() / 2; row++) {
+    memcpy(tmp_row.get(),
+           &pixels[row * row_size],
+           row_size);
+    memcpy(&pixels[row * row_size],
+           &pixels[bitmap_size - (row + 1) * row_size],
+           row_size);
+    memcpy(&pixels[bitmap_size - (row + 1) * row_size],
+           tmp_row.get(),
+           row_size);
+  }
+}
+
 void CompositorGL::MakeCurrent() {
   gl_context_->MakeCurrent(gl_surface_.get());
 }
diff --git a/ui/gfx/compositor/compositor_gl.h b/ui/gfx/compositor/compositor_gl.h
index cc59c68..586e793 100644
--- a/ui/gfx/compositor/compositor_gl.h
+++ b/ui/gfx/compositor/compositor_gl.h
@@ -100,6 +100,9 @@ class COMPOSITOR_EXPORT CompositorGL : public Compositor {
                const gfx::Size& size);
   virtual ~CompositorGL();
 
+  // Overridden from Compositor.
+  virtual void ReadPixels(SkBitmap* bitmap) OVERRIDE;
+
   void MakeCurrent();
   gfx::Size GetSize();
 
diff --git a/ui/gfx/compositor/compositor_win.cc b/ui/gfx/compositor/compositor_win.cc
index 18c71c9..38bf536 100644
--- a/ui/gfx/compositor/compositor_win.cc
+++ b/ui/gfx/compositor/compositor_win.cc
@@ -105,6 +105,8 @@ class CompositorWin : public Compositor {
 
   virtual void Blur(const gfx::Rect& bounds) OVERRIDE;
 
+  virtual void ReadPixels(SkBitmap* bitmap) OVERRIDE;
+
  protected:
   virtual void OnNotifyStart(bool clear) OVERRIDE;
   virtual void OnNotifyEnd() OVERRIDE;
@@ -501,6 +503,10 @@ void CompositorWin::Blur(const gfx::Rect& bounds) {
 #endif
 }
 
+void CompositorWin::ReadPixels(SkBitmap* bitmap) {
+  NOTIMPLEMENTED();
+}
+
 void CompositorWin::OnWidgetSizeChanged() {
   dest_render_target_view_ = NULL;
   depth_stencil_buffer_ = NULL;
diff --git a/ui/gfx/compositor/layer_unittest.cc b/ui/gfx/compositor/layer_unittest.cc
index 9443ab0..402488c 100644
--- a/ui/gfx/compositor/layer_unittest.cc
+++ b/ui/gfx/compositor/layer_unittest.cc
@@ -183,12 +183,14 @@ class NullLayerDelegate : public LayerDelegate {
 #define MAYBE_DrawTree DISABLED_DrawTree
 #define MAYBE_Hierarchy DISABLED_Hierarchy
 #define MAYBE_HierarchyNoTexture DISABLED_HierarchyNoTexture
+#define MAYBE_DrawPixels DISABLED_DrawPixels
 #else
 #define MAYBE_Delegate Delegate
 #define MAYBE_Draw Draw
 #define MAYBE_DrawTree DrawTree
 #define MAYBE_Hierarchy Hierarchy
 #define MAYBE_HierarchyNoTexture HierarchyNoTexture
+#define MAYBE_DrawPixels DrawPixels
 #endif
 
 TEST_F(LayerWithRealCompositorTest, MAYBE_Draw) {
@@ -713,4 +715,22 @@ TEST_F(LayerWithNullDelegateTest, Visibility) {
 #endif
 }
 
+// Checks that pixels are actually drawn to the screen with a read back.
+TEST_F(LayerWithRealCompositorTest, MAYBE_DrawPixels) {
+  scoped_ptr<Layer> layer(CreateColorLayer(SK_ColorRED,
+                                           gfx::Rect(0, 0, 500, 500)));
+  DrawTree(layer.get());
+
+  SkBitmap bitmap;
+  GetCompositor()->ReadPixels(&bitmap);
+
+  SkAutoLockPixels lock(bitmap);
+  bool is_all_red = true;
+  for (int x = 0; is_all_red && x < 500; x++)
+    for (int y = 0; is_all_red && y < 500; y++)
+      is_all_red = is_all_red && (bitmap.getColor(x, y) == SK_ColorRED);
+
+  EXPECT_TRUE(is_all_red);
+}
+
 } // namespace ui
diff --git a/ui/gfx/compositor/test_compositor.cc b/ui/gfx/compositor/test_compositor.cc
index 4bc6faa..c21a13e 100644
--- a/ui/gfx/compositor/test_compositor.cc
+++ b/ui/gfx/compositor/test_compositor.cc
@@ -48,6 +48,9 @@ void TestCompositor::DrawTree() {
 #endif
 }
 
+void TestCompositor::ReadPixels(SkBitmap* bitmap) {
+}
+
 ui::Compositor* TestCompositor::Create(ui::CompositorDelegate* owner) {
   return new ui::TestCompositor(owner);
 }
diff --git a/ui/gfx/compositor/test_compositor.h b/ui/gfx/compositor/test_compositor.h
index 6472496..791ef05 100644
--- a/ui/gfx/compositor/test_compositor.h
+++ b/ui/gfx/compositor/test_compositor.h
@@ -27,6 +27,7 @@ class TestCompositor : public ui::Compositor {
   virtual void OnNotifyEnd() OVERRIDE;
   virtual void Blur(const gfx::Rect& bounds) OVERRIDE;
   virtual void DrawTree() OVERRIDE;
+  virtual void ReadPixels(SkBitmap* bitmap) OVERRIDE;
 
   // A simple factory that creates a test compositor with a given delegate
   static ui::Compositor* Create(ui::CompositorDelegate* owner);