Removal of dependencies on PlatformDevice classes.

skia/ext/platform_canvas.h

Index: skia/ext/platform_canvas.h
===================================================================
--- skia/ext/platform_canvas.h	(revision 85672)
+++ skia/ext/platform_canvas.h	(working copy)
@@ -69,10 +69,10 @@
   // Call endPlatformPaint when you are done and want to use Skia operations
   // after calling the platform-specific beginPlatformPaint; this will
   // synchronize the bitmap to OS if necessary.
-  PlatformDevice::PlatformSurface beginPlatformPaint() const;
+  skia::platform_util::PlatformSurface beginPlatformPaint() const;

[alokp, 2011/05/18 03:25:42]

do we need these member functions? Can't we directly use the functions below in
skia namespace?

[Jeff Timanus, 2011/05/18 22:10:28]

Yes, the functions below can be directly used.  

Done.

   void endPlatformPaint() const;
 
-  // Returns the platform device pointer of the topmost rect with a non-empty
+  // Returns the SkDevice  pointer of the topmost rect with a non-empty
   // clip. In practice, this is usually either the top layer or nothing, since
   // we usually set the clip to new layers when we make them.
   //
@@ -85,7 +85,7 @@
   //
   // Danger: the resulting device should not be saved. It will be invalidated
   // by the next call to save() or restore().
-  PlatformDevice& getTopPlatformDevice() const;
+  SkDevice& getTopDevice() const;

[alokp, 2011/05/18 03:25:42]

SkCanvas also has a function named getTopDevice(). It would also return the same
object. One caveat is that when I used it last time, it caused many regressions.
I guess getting the device through an iterator changes a few other things as
well. It would be better to use SKCanvas::getTopDevice() if we can.

[Jeff Timanus, 2011/05/18 22:10:28]

I looked into the difference of behaviour between SkCanvas::getTopDevice, and
this code, and it seems that the layer iter is performing quite a few operations
on the canvas and top device:
  - SkCanvas::prepareForDeviceDraw
  - SkDevice::accessBitmap(true)

I would prefer to leave removal of this override until aver this CL has landed,
as the changes to ensure the correct behaviour using SkCanvas::getTopDevice
appear non-trivial.

 
   // Return the stride (length of a line in bytes) for the given width. Because
   // we use 32-bits per pixel, this will be roughly 4*width. However, for
@@ -133,7 +133,8 @@
 //
 // Note: These functions will eventually replace
 // PlatformCanvas::beginPlatformPaint and PlatformCanvas::endPlatformPaint.
-SK_API PlatformDevice::PlatformSurface BeginPlatformPaint(SkCanvas* canvas);
+SK_API skia::platform_util::PlatformSurface BeginPlatformPaint(
+    SkCanvas* canvas);
 SK_API void EndPlatformPaint(SkCanvas* canvas);
 
 }  // namespace skia