ozone: Support building without cairo

skia/ext/bitmap_platform_device_linux.h

-// Copyright (c) 2012 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_BITMAP_PLATFORM_DEVICE_LINUX_H_
-#define SKIA_EXT_BITMAP_PLATFORM_DEVICE_LINUX_H_
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "base/memory/ref_counted.h"
-#include "skia/ext/platform_device.h"
-
-typedef struct _cairo_surface cairo_surface_t;
-
-// -----------------------------------------------------------------------------
-// Image byte ordering on Linux:
-//
-// Pixels are packed into 32-bit words these days. Even for 24-bit images,
-// often 8-bits will be left unused for alignment reasons. Thus, when you see
-// ARGB as the byte order you have to wonder if that's in memory order or
-// little-endian order. Here I'll write A.R.G.B to specifiy the memory order.
-//
-// GdkPixbuf's provide a nice backing store and defaults to R.G.B.A order.
-// They'll do the needed byte swapping to match the X server when drawn.
-//
-// Skia can be controled in skia/include/corecg/SkUserConfig.h (see bits about
-// SK_R32_SHIFT). For Linux we define it to be ARGB in registers. For little
-// endian machines that means B.G.R.A in memory.
-//
-// The image loaders are controlled in
-// webkit/port/platform/image-decoders/ImageDecoder.h (see setRGBA). These are
-// also configured for ARGB in registers.
-//
-// Cairo's only 32-bit mode is ARGB in registers.
-//
-// X servers commonly have a 32-bit visual with xRGB in registers (since they
-// typically don't do alpha blending of drawables at the user level. Composite
-// extensions aside.)
-//
-// We don't use GdkPixbuf because its byte order differs from the rest. Most
-// importantly, it differs from Cairo which, being a system library, is
-// something that we can't easily change.
-// -----------------------------------------------------------------------------
-
-namespace skia {
-
-// -----------------------------------------------------------------------------
-// This is the Linux bitmap backing for Skia. We create a Cairo image surface
-// to store the backing buffer. This buffer is BGRA in memory (on little-endian
-// machines).
-//
-// For now we are also using Cairo to paint to the Drawables so we provide an
-// accessor for getting the surface.
-//
-// This is all quite ok for test_shell. In the future we will want to use
-// shared memory between the renderer and the main process at least. In this
-// case we'll probably create the buffer from a precreated region of memory.
-// -----------------------------------------------------------------------------
-class BitmapPlatformDevice : public SkBitmapDevice, public PlatformDevice {
-  // A reference counted cairo surface
-  class BitmapPlatformDeviceData;
-
- public:
-  // Create a BitmapPlatformDeviceLinux from an already constructed bitmap;
-  // you should probably be using Create(). This may become private later if
-  // we ever have to share state between some native drawing UI and Skia, like
-  // the Windows and Mac versions of this class do.
-  //
-  // This object takes ownership of @data.
-  BitmapPlatformDevice(const SkBitmap& other, BitmapPlatformDeviceData* data);
-  virtual ~BitmapPlatformDevice();
-
-  // Constructs a device with size |width| * |height| with contents initialized
-  // to zero. |is_opaque| should be set if the caller knows the bitmap will be
-  // completely opaque and allows some optimizations.
-  static BitmapPlatformDevice* Create(int width, int height, bool is_opaque);
-
-  // Performs the same construction as Create.
-  // Other ports require a separate construction routine because Create does not
-  // initialize the bitmap to 0.
-  static BitmapPlatformDevice* CreateAndClear(int width, int height,
-                                              bool is_opaque);
-
-  // This doesn't take ownership of |data|. If |data| is NULL, the contents
-  // of the device are initialized to 0.
-  static BitmapPlatformDevice* Create(int width, int height, bool is_opaque,
-                                      uint8_t* data);
-
-  // Overridden from SkBaseDevice:
-  virtual void setMatrixClip(const SkMatrix& transform, const SkRegion& region,
-                             const SkClipStack&) OVERRIDE;
-
-  // Overridden from PlatformDevice:
-  virtual cairo_t* BeginPlatformPaint() OVERRIDE;
-  virtual void DrawToNativeContext(PlatformSurface surface, int x, int y,
-                                   const PlatformRect* src_rect) OVERRIDE;
-
- protected:
-  virtual SkBaseDevice* onCreateCompatibleDevice(SkBitmap::Config, int width,
-                                                 int height, bool isOpaque,
-                                                 Usage usage) OVERRIDE;
-
- private:
-  static BitmapPlatformDevice* Create(int width, int height, bool is_opaque,
-                                      cairo_surface_t* surface);
-
-  scoped_refptr<BitmapPlatformDeviceData> data_;
-
-  DISALLOW_COPY_AND_ASSIGN(BitmapPlatformDevice);
-};
-
-}  // namespace skia
-
-#endif  // SKIA_EXT_BITMAP_PLATFORM_DEVICE_LINUX_H_