Index: skia/ext/bitmap_platform_device_cairo.h |
diff --git a/skia/ext/bitmap_platform_device_cairo.h b/skia/ext/bitmap_platform_device_cairo.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..5e6a6f3a433dcf480a3b7ca6e218de100218c3ac |
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+++ b/skia/ext/bitmap_platform_device_cairo.h |
@@ -0,0 +1,104 @@ |
+// Copyright 2013 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_CAIRO_H_ |
+#define SKIA_EXT_BITMAP_PLATFORM_DEVICE_CAIRO_H_ |
+ |
+#include <stdint.h> |
+ |
+#include "base/compiler_specific.h" |
+#include "base/macros.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 { |
+ 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 @cairo. |
+ BitmapPlatformDevice(const SkBitmap& other, cairo_t* cairo); |
+ ~BitmapPlatformDevice() override; |
+ |
+ // 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); |
+ |
+ // 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); |
+ |
+ protected: |
+ SkBaseDevice* onCreateDevice(const CreateInfo&, const SkPaint*) override; |
+ |
+ private: |
+ // Overridden from PlatformDevice: |
+ cairo_t* BeginPlatformPaint(const SkMatrix& transform, |
+ const SkIRect& clip_bounds) override; |
+ |
+ static BitmapPlatformDevice* Create(int width, int height, bool is_opaque, |
+ cairo_surface_t* surface); |
+ |
+ // Loads the current transform and clip into the context. |
+ void LoadConfig(const SkMatrix& transform, const SkIRect& clip_bounds); |
+ |
+ // Graphics context used to draw into the surface. |
+ cairo_t* cairo_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(BitmapPlatformDevice); |
+}; |
+ |
+} // namespace skia |
+ |
+#endif // SKIA_EXT_BITMAP_PLATFORM_DEVICE_CAIRO_H_ |