Removal of dependencies on PlatformDevice classes.

skia/ext/platform_canvas.h

 // Copyright (c) 2011 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.
 
 #ifndef SKIA_EXT_PLATFORM_CANVAS_H_
 #define SKIA_EXT_PLATFORM_CANVAS_H_
 #pragma once
 
 // The platform-specific device will include the necessary platform headers
 // to get the surface type.
@@ skipping 51 matching lines @@
 #endif
 
   // Shared --------------------------------------------------------------------
 
   // These calls should surround calls to platform drawing routines, the
   // surface returned here can be used with the native platform routines
   //
   // 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.
   //
   // If there is no layer that is not all clipped out, this will return a
   // dummy device so callers do not have to check. If you are concerned about
   // performance, check the clip before doing any painting.
   //
   // This is different than SkCanvas' getDevice, because that returns the
   // bottommost device.
   //
   // 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
   // alignment reasons we may wish to increase that.
   static size_t StrideForWidth(unsigned width);
 
   // Allow callers to see the non-virtual function even though we have an
   // override of a virtual one.
   // FIXME(brettw) is this necessary?
   using SkCanvas::clipRect;
@@ skipping 27 matching lines @@
 
 // These calls should surround calls to platform drawing routines, the
 // surface returned here can be used with the native platform routines.
 //
 // 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.
 //
 // 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
 
 #endif  // SKIA_EXT_PLATFORM_CANVAS_H_