Roll skia to 8cc209111876b7c78b5ec577c9221d8ed5e21024

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_
-
-// The platform-specific device will include the necessary platform headers
-// to get the surface type.
-#include "base/basictypes.h"
-#include "skia/ext/platform_device.h"
-#include "skia/ext/refptr.h"
-#include "third_party/skia/include/core/SkBitmap.h"
-#include "third_party/skia/include/core/SkCanvas.h"
-#include "third_party/skia/include/core/SkPixelRef.h"
-#include "third_party/skia/include/core/SkPreConfig.h"
-
-namespace skia {
-
-typedef SkCanvas PlatformCanvas;
-
-//
-//  Note about error handling.
-//
-//  Creating a canvas can fail at times, most often because we fail to allocate
-//  the backing-store (pixels). This can be from out-of-memory, or something
-//  more opaque, like GDI or cairo reported a failure.
-//
-//  To allow the caller to handle the failure, every Create... factory takes an
-//  enum as its last parameter. The default value is kCrashOnFailure. If the
-//  caller passes kReturnNullOnFailure, then the caller is responsible to check
-//  the return result.
-//
-enum OnFailureType {
-  CRASH_ON_FAILURE,
-  RETURN_NULL_ON_FAILURE
-};
-
-#if defined(SK_BUILD_FOR_WIN32)
-  // The shared_section parameter is passed to gfx::PlatformDevice::create.
-  // See it for details.
-  SK_API SkCanvas* CreatePlatformCanvas(int width,
-                                        int height,
-                                        bool is_opaque,
-                                        HANDLE shared_section,
-                                        OnFailureType failure_type);
-
-  // Draws the top layer of the canvas into the specified HDC. Only works
-  // with a PlatformCanvas with a BitmapPlatformDevice.
-  SK_API void DrawToNativeContext(SkCanvas* canvas,
-                                  HDC hdc,
-                                  int x,
-                                  int y,
-                                  const RECT* src_rect);
-#elif defined(SK_BUILD_FOR_MAC)
-  SK_API SkCanvas* CreatePlatformCanvas(CGContextRef context,
-                                        int width,
-                                        int height,
-                                        bool is_opaque,
-                                        OnFailureType failure_type);
-
-  SK_API SkCanvas* CreatePlatformCanvas(int width,
-                                        int height,
-                                        bool is_opaque,
-                                        uint8_t* context,
-                                        OnFailureType failure_type);
-#elif defined(SK_BUILD_FOR_ANDROID) || defined(SK_BUILD_FOR_UNIX)
-  // Linux ---------------------------------------------------------------------
-
-  // Construct a canvas from the given memory region. The memory is not cleared
-  // first. @data must be, at least, @height * StrideForWidth(@width) bytes.
-  SK_API SkCanvas* CreatePlatformCanvas(int width,
-                                        int height,
-                                        bool is_opaque,
-                                        uint8_t* data,
-                                        OnFailureType failure_type);
-#endif
-
-static inline SkCanvas* CreatePlatformCanvas(int width,
-                                             int height,
-                                             bool is_opaque) {
-  return CreatePlatformCanvas(width, height, is_opaque, 0, CRASH_ON_FAILURE);
-}
-
-SK_API SkCanvas* CreateCanvas(const skia::RefPtr<SkBaseDevice>& device,
-                              OnFailureType failure_type);
-
-static inline SkCanvas* CreateBitmapCanvas(int width,
-                                           int height,
-                                           bool is_opaque) {
-  return CreatePlatformCanvas(width, height, is_opaque, 0, CRASH_ON_FAILURE);
-}
-
-static inline SkCanvas* TryCreateBitmapCanvas(int width,
-                                              int height,
-                                              bool is_opaque) {
-  return CreatePlatformCanvas(width, height, is_opaque, 0,
-                              RETURN_NULL_ON_FAILURE);
-}
-
-// 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.
-SK_API size_t PlatformCanvasStrideForWidth(unsigned width);
-
-// Returns the SkBaseDevice 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.
-//
-// This may return NULL, so callers need to check.
-//
-// 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().
-SK_API SkBaseDevice* GetTopDevice(const SkCanvas& canvas);
-
-// Returns true if native platform routines can be used to draw on the
-// given canvas. If this function returns false, BeginPlatformPaint will
-// return NULL PlatformSurface.
-SK_API bool SupportsPlatformPaint(const SkCanvas* canvas);
-
-// Sets the opacity of each pixel in the specified region to be opaque.
-SK_API void MakeOpaque(SkCanvas* canvas, int x, int y, int width, int height);
-
-// 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.
-SK_API PlatformSurface BeginPlatformPaint(SkCanvas* canvas);
-SK_API void EndPlatformPaint(SkCanvas* canvas);
-
-// Helper class for pairing calls to BeginPlatformPaint and EndPlatformPaint.
-// Upon construction invokes BeginPlatformPaint, and upon destruction invokes
-// EndPlatformPaint.
-class SK_API ScopedPlatformPaint {
- public:
-  explicit ScopedPlatformPaint(SkCanvas* canvas) : canvas_(canvas) {
-    platform_surface_ = BeginPlatformPaint(canvas);
-  }
-  ~ScopedPlatformPaint() { EndPlatformPaint(canvas_); }
-
-  // Returns the PlatformSurface to use for native platform drawing calls.
-  PlatformSurface GetPlatformSurface() { return platform_surface_; }
- private:
-  SkCanvas* canvas_;
-  PlatformSurface platform_surface_;
-
-  // Disallow copy and assign
-  ScopedPlatformPaint(const ScopedPlatformPaint&);
-  ScopedPlatformPaint& operator=(const ScopedPlatformPaint&);
-};
-
-// PlatformBitmap holds a PlatformSurface that can also be used as an SkBitmap.
-class SK_API PlatformBitmap {
- public:
-  PlatformBitmap();
-  ~PlatformBitmap();
-
-  // Returns true if the bitmap was able to allocate its surface.
-  bool Allocate(int width, int height, bool is_opaque);
-
-  // Returns the platform surface, or 0 if Allocate() did not return true.
-  PlatformSurface GetSurface() { return surface_; }
-
-  // Return the skia bitmap, which will be empty if Allocate() did not
-  // return true.
-  //
-  // The resulting SkBitmap holds a refcount on the underlying platform surface,
-  // so the surface will remain allocated so long as the SkBitmap or its copies
-  // stay around.
-  const SkBitmap& GetBitmap() { return bitmap_; }
-
- private:
-  SkBitmap bitmap_;
-  PlatformSurface surface_;  // initialized to 0
-  intptr_t platform_extra_;  // platform specific, initialized to 0
-
-  DISALLOW_COPY_AND_ASSIGN(PlatformBitmap);
-};
-
-}  // namespace skia
-
-#endif  // SKIA_EXT_PLATFORM_CANVAS_H_