diff options
Diffstat (limited to 'skia/ext/platform_canvas.h')
| -rw-r--r-- | skia/ext/platform_canvas.h | 122 |
1 files changed, 109 insertions, 13 deletions
diff --git a/skia/ext/platform_canvas.h b/skia/ext/platform_canvas.h index e0883e3..f16fa1f 100644 --- a/skia/ext/platform_canvas.h +++ b/skia/ext/platform_canvas.h @@ -2,26 +2,122 @@ // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. -// Declare a platform-neutral name for this platform's canvas class -// that can be used by upper-level classes that just need to pass a reference -// around. +#ifndef SKIA_EXT_PLATFORM_CANVAS_H_ +#define SKIA_EXT_PLATFORM_CANVAS_H_ -#if defined(WIN32) -#include "skia/ext/platform_canvas_win.h" -#elif defined(__APPLE__) -#include "skia/ext/platform_canvas_mac.h" -#elif defined(__linux__) -#include "skia/ext/platform_canvas_linux.h" -#endif +// The platform-specific device will include the necessary platform headers +// to get the surface type. +#include "skia/ext/platform_device.h" +#include "third_party/skia/include/core/SkCanvas.h" namespace skia { +// This class is a specialization of the regular SkCanvas that is designed to +// work with a PlatformDevice to manage platform-specific drawing. It allows +// using both Skia operations and platform-specific operations. +class PlatformCanvas : public SkCanvas { + public: + // Set is_opaque if you are going to erase the bitmap and not use + // transparency: this will enable some optimizations. + // If you use the version with no arguments, you MUST call initialize() + PlatformCanvas(); + PlatformCanvas(int width, int height, bool is_opaque); + virtual ~PlatformCanvas(); + #if defined(WIN32) -typedef PlatformCanvasWin PlatformCanvas; + // Windows ------------------------------------------------------------------ + + // The shared_section parameter is passed to gfx::PlatformDevice::create. + // See it for details. + PlatformCanvas(int width, int height, bool is_opaque, HANDLE shared_section); + + // For two-part init, call if you use the no-argument constructor above. Note + // that we want this to optionally match the Linux initialize if you only + // pass 3 arguments, hence the evil default argument. + bool initialize(int width, int height, bool is_opaque, + HANDLE shared_section = NULL); + #elif defined(__APPLE__) -typedef PlatformCanvasMac PlatformCanvas; + // Mac ----------------------------------------------------------------------- + + PlatformCanvas(int width, int height, bool is_opaque, + CGContextRef context); + PlatformCanvas(int width, int height, bool is_opaque, uint8_t* context); + + // For two-part init, call if you use the no-argument constructor above + bool initialize(int width, int height, bool is_opaque, uint8_t* data = NULL); + #elif defined(__linux__) -typedef PlatformCanvasLinux PlatformCanvas; + // Linux --------------------------------------------------------------------- + + // Construct a canvas from the given memory region. The memory is not cleared + // first. @data must be, at least, @height * StrideForWidth(@width) bytes. + PlatformCanvas(int width, int height, bool is_opaque, uint8_t* data); + + // For two-part init, call if you use the no-argument constructor above + bool initialize(int width, int height, bool is_opaque, uint8_t* data = NULL); + #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(); + void endPlatformPaint(); + + // Returns the platform device 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; + + // 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; + + protected: + // Creates a device store for use by the canvas. We override this so that + // the device is always our own so we know that we can use platform + // operations on it. + virtual SkDevice* createDevice(SkBitmap::Config, + int width, + int height, + bool is_opaque, + bool isForLayer); + + private: + // Unimplemented. This is to try to prevent people from calling this function + // on SkCanvas. SkCanvas' version is not virtual, so we can't prevent this + // 100%, but hopefully this will make people notice and not use the function. + // Calling SkCanvas' version will create a new device which is not compatible + // with us and we will crash if somebody tries to draw into it with + // CoreGraphics. + virtual SkDevice* setBitmapDevice(const SkBitmap& bitmap); + + // Disallow copy and assign. + PlatformCanvas(const PlatformCanvas&); + PlatformCanvas& operator=(const PlatformCanvas&); +}; } // namespace skia + +#endif // SKIA_EXT_PLATFORM_CANVAS_H_ |