cc: Adding support for RGBA_4444 tile textures

cc/resources/raster_worker_pool.cc

Index: cc/resources/raster_worker_pool.cc
diff --git a/cc/resources/raster_worker_pool.cc b/cc/resources/raster_worker_pool.cc
index 15b8aa41133312b094cec77d073ab1c5c954e41f..fc6c2ddfaa921959a4482f9265ebc18c803d1955 100644
--- a/cc/resources/raster_worker_pool.cc
+++ b/cc/resources/raster_worker_pool.cc
@@ -11,13 +11,28 @@
 #include "cc/debug/devtools_instrumentation.h"
 #include "cc/debug/traced_value.h"
 #include "cc/resources/picture_pile_impl.h"
+#include "cc/resources/resource_provider.h"
 #include "skia/ext/lazy_pixel_ref.h"
 #include "skia/ext/paint_simplifier.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 
 namespace cc {
 
 namespace {
 
+// Subclass of Allocator that takes a suitably allocated pointer and uses
+// it as the pixel memory for the bitmap.
+class IdentityAllocator : public SkBitmap::Allocator {
+ public:
+  explicit IdentityAllocator(void* buffer) : buffer_(buffer) {}
+  virtual bool allocPixelRef(SkBitmap* dst, SkColorTable*) OVERRIDE {
+    dst->setPixels(buffer_);
+    return true;
+  }
+ private:
+  void* buffer_;
+};
+
 // Flag to indicate whether we should try and detect that
 // a tile is of solid color.
 const bool kUseColorEstimator = true;
@@ -60,7 +75,8 @@ class RasterWorkerPoolTaskImpl : public internal::RasterWorkerPoolTask {
         tile_id_(tile_id),
         source_frame_number_(source_frame_number),
         rendering_stats_(rendering_stats),
-        reply_(reply) {}
+        reply_(reply),
+        texture_format_(resource->format()) {}
 
   void RunAnalysisOnThread(unsigned thread_index) {
     TRACE_EVENT1("cc",
@@ -89,7 +105,10 @@ class RasterWorkerPoolTaskImpl : public internal::RasterWorkerPoolTask {
     analysis_.is_solid_color &= kUseColorEstimator;
   }
 
-  bool RunRasterOnThread(SkBaseDevice* device, unsigned thread_index) {
+  bool RunRasterOnThread(unsigned thread_index,
+                         void* buffer,
+                         gfx::Size size,
+                         int stride) {
     TRACE_EVENT2(
         benchmark_instrumentation::kCategory,
         benchmark_instrumentation::kRunRasterOnThread,
@@ -102,7 +121,7 @@ class RasterWorkerPoolTaskImpl : public internal::RasterWorkerPoolTask {
         devtools_instrumentation::kRasterTask, layer_id_);
 
     DCHECK(picture_pile_.get());
-    DCHECK(device);
+    DCHECK(buffer);
 
     if (analysis_.is_solid_color)
       return false;
@@ -110,8 +129,24 @@ class RasterWorkerPoolTaskImpl : public internal::RasterWorkerPoolTask {
     PicturePileImpl* picture_clone =
         picture_pile_->GetCloneForDrawingOnThread(thread_index);
 
-    SkCanvas canvas(device);
+    SkBitmap bitmap_32;

[reveman, 2013/09/13 14:32:49]

can we drop the _32 suffix here?

[kaanb, 2013/09/13 19:57:39]

Done.

+    bitmap_32.setConfig(SkBitmap::kARGB_8888_Config,
+                        size.width(),
+                        size.height(),
+                        stride);

[reveman, 2013/09/13 14:32:49]

stride is not going to be correct here unless format is RGBA_8888 or BGRA_8888.
you should probably move this into the switch statement and not set stride in
the case of RGBA_4444.

[kaanb, 2013/09/13 19:57:39]

Done.

+    switch (texture_format_) {
+      case ResourceProvider::RGBA_4444:
+        bitmap_32.allocPixels();
+        break;
+      case ResourceProvider::RGBA_8888:
+      case ResourceProvider::BGRA_8888:
+      case ResourceProvider::LUMINANCE_8:

[reveman, 2013/09/13 14:32:49]

Using SkBitmap::kARGB_8888_Config for LUMINANCE_8 doesn't look right. I'd rather
we make it explicit that this format is not supported.

[kaanb, 2013/09/13 19:57:39]

Done.

+        bitmap_32.setPixels(buffer);
+        break;
+    }
 
+    SkBitmapDevice device_32(bitmap_32);

[reveman, 2013/09/13 14:32:49]

drop _32?

[kaanb, 2013/09/13 19:57:39]

Done.

+    SkCanvas canvas(&device_32);
     skia::RefPtr<SkDrawFilter> draw_filter;
     switch (raster_mode_) {
       case LOW_QUALITY_RASTER_MODE:
@@ -149,14 +184,26 @@ class RasterWorkerPoolTaskImpl : public internal::RasterWorkerPoolTask {
       picture_clone->RasterToBitmap(
           &canvas, content_rect_, contents_scale_, NULL);
     }
+
+    if (texture_format_ == ResourceProvider::RGBA_4444) {
+      TRACE_EVENT0("cc",
+                   "RasterWorkerPoolTaskImpl::RunRasterOnThread::Downsample");

[reveman, 2013/09/13 14:32:49]

If this is worth a trace event then I prefer if you moved it to a helper
function.

[kaanb, 2013/09/13 19:57:39]

Done.

+      SkBitmap bitmap_16;
+      IdentityAllocator allocator(buffer);
+      bitmap_32.copyTo(&bitmap_16, SkBitmap::kARGB_4444_Config, &allocator);
+    }

[reveman, 2013/09/13 14:32:49]

This is currently hardcoded to only support RGBA_4444. I think it needs to be
generalized a bit. Maybe add a SkBitmapConfigFromFormat helper function that
determines the config to use with copyTo and you can also use that to determine
if the copy is needed. ie. bitmap.getConfig() !=
SkBitmapConfigFromFormat(format).

[kaanb, 2013/09/13 19:57:39]

Done.

+
     return true;
   }
 
   // Overridden from internal::RasterWorkerPoolTask:
-  virtual bool RunOnWorkerThread(SkBaseDevice* device, unsigned thread_index)
+  virtual bool RunOnWorkerThread(unsigned thread_index,
+                                 void* buffer,
+                                 gfx::Size size,
+                                 int stride)
       OVERRIDE {
     RunAnalysisOnThread(thread_index);
-    return RunRasterOnThread(device, thread_index);
+    return RunRasterOnThread(thread_index, buffer, size, stride);
   }
   virtual void CompleteOnOriginThread() OVERRIDE {
     reply_.Run(analysis_, !HasFinishedRunning() || WasCanceled());
@@ -189,6 +236,7 @@ class RasterWorkerPoolTaskImpl : public internal::RasterWorkerPoolTask {
   int source_frame_number_;
   RenderingStatsInstrumentation* rendering_stats_;
   const RasterWorkerPool::RasterTask::Reply reply_;
+  ResourceProvider::Format texture_format_;

[reveman, 2013/09/13 14:32:49]

I don't think you need this. You can get the format from resource()->format().

[kaanb, 2013/09/13 19:57:39]

Done.

 
   DISALLOW_COPY_AND_ASSIGN(RasterWorkerPoolTaskImpl);
 };