gfx/canvas_skia.cc - chromium/src.git - Git at Google

 // Copyright (c) 2010 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.

 #include "gfx/canvas_skia.h"

 #include <limits>

 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "gfx/brush.h"
 #include "gfx/font.h"
 #include "gfx/rect.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"

 #if defined(OS_WIN)
 #include "gfx/canvas_skia_paint.h"
 #endif

 namespace {

 // A platform wrapper for a Skia shader that makes sure the underlying
 // SkShader object is unref'ed when this object is destroyed.
 class SkiaShader : public gfx::Brush {
  public:
   explicit SkiaShader(SkShader* shader) : shader_(shader) {
   }
   virtual ~SkiaShader() {
     shader_->unref();
   }

   // Accessor for shader, so it can be associated with a SkPaint.
   SkShader* shader() const { return shader_; }

  private:
   SkShader* shader_;

   DISALLOW_COPY_AND_ASSIGN(SkiaShader);
 };


 }  // namespace

 namespace gfx {

 ////////////////////////////////////////////////////////////////////////////////
 // CanvasSkia, public:

 // static
 int CanvasSkia::DefaultCanvasTextAlignment() {
   if (!base::i18n::IsRTL())
     return gfx::Canvas::TEXT_ALIGN_LEFT;
   return gfx::Canvas::TEXT_ALIGN_RIGHT;
 }

 SkBitmap CanvasSkia::ExtractBitmap() const {
   const SkBitmap& device_bitmap = getDevice()->accessBitmap(false);

   // Make a bitmap to return, and a canvas to draw into it. We don't just want
   // to call extractSubset or the copy constructor, since we want an actual copy
   // of the bitmap.
   SkBitmap result;
   device_bitmap.copyTo(&result, SkBitmap::kARGB_8888_Config);
   return result;
 }

 ////////////////////////////////////////////////////////////////////////////////
 // CanvasSkia, Canvas implementation:

 void CanvasSkia::Save() {
   save();
 }

 void CanvasSkia::SaveLayerAlpha(uint8 alpha) {
   saveLayerAlpha(NULL, alpha);
 }


 void CanvasSkia::SaveLayerAlpha(uint8 alpha, const gfx::Rect& layer_bounds) {
   SkRect bounds;
   bounds.set(SkIntToScalar(layer_bounds.x()),
              SkIntToScalar(layer_bounds.y()),
              SkIntToScalar(layer_bounds.right()),
              SkIntToScalar(layer_bounds.bottom()));
   saveLayerAlpha(&bounds, alpha);
 }

 void CanvasSkia::Restore() {
   restore();
 }

 bool CanvasSkia::ClipRectInt(int x, int y, int w, int h) {
   SkRect new_clip;
   new_clip.set(SkIntToScalar(x), SkIntToScalar(y),
                SkIntToScalar(x + w), SkIntToScalar(y + h));
   return clipRect(new_clip);
 }

 void CanvasSkia::TranslateInt(int x, int y) {
   translate(SkIntToScalar(x), SkIntToScalar(y));
 }

 void CanvasSkia::ScaleInt(int x, int y) {
   scale(SkIntToScalar(x), SkIntToScalar(y));
 }

 void CanvasSkia::FillRectInt(const SkColor& color, int x, int y, int w, int h) {
   SkPaint paint;
   paint.setColor(color);
   paint.setStyle(SkPaint::kFill_Style);
   paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
   DrawRectInt(x, y, w, h, paint);
 }

 void CanvasSkia::FillRectInt(const gfx::Brush* brush,
                              int x, int y, int w, int h) {
   const SkiaShader* shader = static_cast<const SkiaShader*>(brush);
   SkPaint paint;
   paint.setShader(shader->shader());
   // TODO(beng): set shader transform to match canvas transform.
   DrawRectInt(x, y, w, h, paint);
 }

 void CanvasSkia::DrawRectInt(const SkColor& color, int x, int y, int w, int h) {
   DrawRectInt(color, x, y, w, h, SkXfermode::kSrcOver_Mode);
 }

 void CanvasSkia::DrawRectInt(const SkColor& color,
                              int x, int y, int w, int h,
                              SkXfermode::Mode mode) {
   SkPaint paint;
   paint.setColor(color);
   paint.setStyle(SkPaint::kStroke_Style);
   // Set a stroke width of 0, which will put us down the stroke rect path.  If
   // we set a stroke width of 1, for example, this will internally create a
   // path and fill it, which causes problems near the edge of the canvas.
   paint.setStrokeWidth(SkIntToScalar(0));
   paint.setXfermodeMode(mode);

   DrawRectInt(x, y, w, h, paint);
 }

 void CanvasSkia::DrawRectInt(int x, int y, int w, int h, const SkPaint& paint) {
   SkIRect rc = { x, y, x + w, y + h };
   drawIRect(rc, paint);
 }

 void CanvasSkia::DrawLineInt(const SkColor& color,
                              int x1, int y1,
                              int x2, int y2) {
   SkPaint paint;
   paint.setColor(color);
   paint.setStrokeWidth(SkIntToScalar(1));
   drawLine(SkIntToScalar(x1), SkIntToScalar(y1), SkIntToScalar(x2),
            SkIntToScalar(y2), paint);
 }

 void CanvasSkia::DrawFocusRect(int x, int y, int width, int height) {
   // Create a 2D bitmap containing alternating on/off pixels - we do this
   // so that you never get two pixels of the same color around the edges
   // of the focus rect (this may mean that opposing edges of the rect may
   // have a dot pattern out of phase to each other).
   static SkBitmap* dots = NULL;
   if (!dots) {
     int col_pixels = 32;
     int row_pixels = 32;

     dots = new SkBitmap;
     dots->setConfig(SkBitmap::kARGB_8888_Config, col_pixels, row_pixels);
     dots->allocPixels();
     dots->eraseARGB(0, 0, 0, 0);

     uint32_t* dot = dots->getAddr32(0, 0);
     for (int i = 0; i < row_pixels; i++) {
       for (int u = 0; u < col_pixels; u++) {
         if ((u % 2 + i % 2) % 2 != 0) {
           dot[i * row_pixels + u] = SK_ColorGRAY;
         }
       }
     }
   }

   // First the horizontal lines.

   // Make a shader for the bitmap with an origin of the box we'll draw. This
   // shader is refcounted and will have an initial refcount of 1.
   SkShader* shader = SkShader::CreateBitmapShader(
       *dots, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
   // Assign the shader to the paint & release our reference. The paint will
   // now own the shader and the shader will be destroyed when the paint goes
   // out of scope.
   SkPaint paint;
   paint.setShader(shader);
   shader->unref();

   DrawRectInt(x, y, width, 1, paint);
   DrawRectInt(x, y + height - 1, width, 1, paint);
   DrawRectInt(x, y, 1, height, paint);
   DrawRectInt(x + width - 1, y, 1, height, paint);
 }

 void CanvasSkia::DrawBitmapInt(const SkBitmap& bitmap, int x, int y) {
   drawBitmap(bitmap, SkIntToScalar(x), SkIntToScalar(y));
 }

 void CanvasSkia::DrawBitmapInt(const SkBitmap& bitmap,
                                int x, int y,
                                const SkPaint& paint) {
   drawBitmap(bitmap, SkIntToScalar(x), SkIntToScalar(y), &paint);
 }

 void CanvasSkia::DrawBitmapInt(const SkBitmap& bitmap,
                                int src_x, int src_y, int src_w, int src_h,
                                int dest_x, int dest_y, int dest_w, int dest_h,
                                bool filter) {
   SkPaint p;
   DrawBitmapInt(bitmap, src_x, src_y, src_w, src_h, dest_x, dest_y,
                 dest_w, dest_h, filter, p);
 }

 void CanvasSkia::DrawBitmapInt(const SkBitmap& bitmap,
                                int src_x, int src_y, int src_w, int src_h,
                                int dest_x, int dest_y, int dest_w, int dest_h,
                                bool filter,
                                const SkPaint& paint) {
   DLOG_ASSERT(src_x + src_w < std::numeric_limits<int16_t>::max() &&
               src_y + src_h < std::numeric_limits<int16_t>::max());
   if (src_w <= 0 || src_h <= 0 || dest_w <= 0 || dest_h <= 0) {
     NOTREACHED() << "Attempting to draw bitmap to/from an empty rect!";
     return;
   }

   if (!IntersectsClipRectInt(dest_x, dest_y, dest_w, dest_h))
     return;

   SkRect dest_rect = { SkIntToScalar(dest_x),
                        SkIntToScalar(dest_y),
                        SkIntToScalar(dest_x + dest_w),
                        SkIntToScalar(dest_y + dest_h) };

   if (src_w == dest_w && src_h == dest_h) {
     // Workaround for apparent bug in Skia that causes image to occasionally
     // shift.
     SkIRect src_rect = { src_x, src_y, src_x + src_w, src_y + src_h };
     drawBitmapRect(bitmap, &src_rect, dest_rect, &paint);
     return;
   }

   // Make a bitmap shader that contains the bitmap we want to draw. This is
   // basically what SkCanvas.drawBitmap does internally, but it gives us
   // more control over quality and will use the mipmap in the source image if
   // it has one, whereas drawBitmap won't.
   SkShader* shader = SkShader::CreateBitmapShader(bitmap,
                                                   SkShader::kRepeat_TileMode,
                                                   SkShader::kRepeat_TileMode);
   SkMatrix shader_scale;
   shader_scale.setScale(SkFloatToScalar(static_cast<float>(dest_w) / src_w),
                         SkFloatToScalar(static_cast<float>(dest_h) / src_h));
   shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
   shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));
   shader->setLocalMatrix(shader_scale);

   // Set up our paint to use the shader & release our reference (now just owned
   // by the paint).
   SkPaint p(paint);
   p.setFilterBitmap(filter);
   p.setShader(shader);
   shader->unref();

   // The rect will be filled by the bitmap.
   drawRect(dest_rect, p);
 }

 void CanvasSkia::DrawStringInt(const std::wstring& text,
                                const gfx::Font& font,
                                const SkColor& color,
                                int x, int y, int w, int h) {
   DrawStringInt(text, font, color, x, y, w, h,
                 gfx::CanvasSkia::DefaultCanvasTextAlignment());
 }

 void CanvasSkia::DrawStringInt(const std::wstring& text,
                                const gfx::Font& font,
                                const SkColor& color,
                                const gfx::Rect& display_rect) {
   DrawStringInt(text, font, color, display_rect.x(), display_rect.y(),
                 display_rect.width(), display_rect.height());
 }

 void CanvasSkia::TileImageInt(const SkBitmap& bitmap,
                               int x, int y, int w, int h) {
   TileImageInt(bitmap, 0, 0, x, y, w, h);
 }

 void CanvasSkia::TileImageInt(const SkBitmap& bitmap,
                               int src_x, int src_y,
                               int dest_x, int dest_y, int w, int h) {
   if (!IntersectsClipRectInt(dest_x, dest_y, w, h))
     return;

   SkPaint paint;

   SkShader* shader = SkShader::CreateBitmapShader(bitmap,
                                                   SkShader::kRepeat_TileMode,
                                                   SkShader::kRepeat_TileMode);
   paint.setShader(shader);
   paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);

   // CreateBitmapShader returns a Shader with a reference count of one, we
   // need to unref after paint takes ownership of the shader.
   shader->unref();
   save();
   translate(SkIntToScalar(dest_x - src_x), SkIntToScalar(dest_y - src_y));
   ClipRectInt(src_x, src_y, w, h);
   drawPaint(paint);
   restore();
 }

 gfx::NativeDrawingContext CanvasSkia::BeginPlatformPaint() {
   return beginPlatformPaint();
 }

 void CanvasSkia::EndPlatformPaint() {
   endPlatformPaint();
 }

 CanvasSkia* CanvasSkia::AsCanvasSkia() {
   return this;
 }

 const CanvasSkia* CanvasSkia::AsCanvasSkia() const {
   return this;
 }

 ////////////////////////////////////////////////////////////////////////////////
 // CanvasSkia, private:

 bool CanvasSkia::IntersectsClipRectInt(int x, int y, int w, int h) {
   SkRect clip;
   return getClipBounds(&clip) &&
       clip.intersect(SkIntToScalar(x), SkIntToScalar(y), SkIntToScalar(x + w),
                      SkIntToScalar(y + h));
 }

 ////////////////////////////////////////////////////////////////////////////////
 // Canvas, public:

 Canvas* Canvas::CreateCanvas() {
   return new CanvasSkia;
 }

 Canvas* Canvas::CreateCanvas(int width, int height, bool is_opaque) {
   return new CanvasSkia(width, height, is_opaque);
 }

 #if defined(OS_WIN)
 // TODO(beng): move to canvas_win.cc, etc.
 class CanvasPaintWin : public CanvasSkiaPaint, public CanvasPaint {
  public:
   CanvasPaintWin(gfx::NativeView view) : CanvasSkiaPaint(view) {}

   // Overridden from CanvasPaint2:
   virtual bool IsValid() const {
     return isEmpty();
   }

   virtual gfx::Rect GetInvalidRect() const {
     return gfx::Rect(paintStruct().rcPaint);
   }

   virtual Canvas* AsCanvas() {
     return this;
   }
 };
 #endif

 CanvasPaint* CanvasPaint::CreateCanvasPaint(gfx::NativeView view) {
 #if defined(OS_WIN)
   return new CanvasPaintWin(view);
 #else
   return NULL;
 #endif
 }

 }  // namespace gfx
	// Copyright (c) 2010 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.

	#include "gfx/canvas_skia.h"

	#include <limits>

	#include "base/i18n/rtl.h"
	#include "base/logging.h"
	#include "gfx/brush.h"
	#include "gfx/font.h"
	#include "gfx/rect.h"
	#include "third_party/skia/include/effects/SkGradientShader.h"

	#if defined(OS_WIN)
	#include "gfx/canvas_skia_paint.h"
	#endif

	namespace {

	// A platform wrapper for a Skia shader that makes sure the underlying
	// SkShader object is unref'ed when this object is destroyed.
	class SkiaShader : public gfx::Brush {
	public:
	explicit SkiaShader(SkShader* shader) : shader_(shader) {
	}
	virtual ~SkiaShader() {
	shader_->unref();
	}

	// Accessor for shader, so it can be associated with a SkPaint.
	SkShader* shader() const { return shader_; }

	private:
	SkShader* shader_;

	DISALLOW_COPY_AND_ASSIGN(SkiaShader);
	};


	} // namespace

	namespace gfx {

	////////////////////////////////////////////////////////////////////////////////
	// CanvasSkia, public:

	// static
	int CanvasSkia::DefaultCanvasTextAlignment() {
	if (!base::i18n::IsRTL())
	return gfx::Canvas::TEXT_ALIGN_LEFT;
	return gfx::Canvas::TEXT_ALIGN_RIGHT;
	}

	SkBitmap CanvasSkia::ExtractBitmap() const {
	const SkBitmap& device_bitmap = getDevice()->accessBitmap(false);

	// Make a bitmap to return, and a canvas to draw into it. We don't just want
	// to call extractSubset or the copy constructor, since we want an actual copy
	// of the bitmap.
	SkBitmap result;
	device_bitmap.copyTo(&result, SkBitmap::kARGB_8888_Config);
	return result;
	}

	////////////////////////////////////////////////////////////////////////////////
	// CanvasSkia, Canvas implementation:

	void CanvasSkia::Save() {
	save();
	}

	void CanvasSkia::SaveLayerAlpha(uint8 alpha) {
	saveLayerAlpha(NULL, alpha);
	}


	void CanvasSkia::SaveLayerAlpha(uint8 alpha, const gfx::Rect& layer_bounds) {
	SkRect bounds;
	bounds.set(SkIntToScalar(layer_bounds.x()),
	SkIntToScalar(layer_bounds.y()),
	SkIntToScalar(layer_bounds.right()),
	SkIntToScalar(layer_bounds.bottom()));
	saveLayerAlpha(&bounds, alpha);
	}

	void CanvasSkia::Restore() {
	restore();
	}

	bool CanvasSkia::ClipRectInt(int x, int y, int w, int h) {
	SkRect new_clip;
	new_clip.set(SkIntToScalar(x), SkIntToScalar(y),
	SkIntToScalar(x + w), SkIntToScalar(y + h));
	return clipRect(new_clip);
	}

	void CanvasSkia::TranslateInt(int x, int y) {
	translate(SkIntToScalar(x), SkIntToScalar(y));
	}

	void CanvasSkia::ScaleInt(int x, int y) {
	scale(SkIntToScalar(x), SkIntToScalar(y));
	}

	void CanvasSkia::FillRectInt(const SkColor& color, int x, int y, int w, int h) {
	SkPaint paint;
	paint.setColor(color);
	paint.setStyle(SkPaint::kFill_Style);
	paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
	DrawRectInt(x, y, w, h, paint);
	}

	void CanvasSkia::FillRectInt(const gfx::Brush* brush,
	int x, int y, int w, int h) {
	const SkiaShader* shader = static_cast<const SkiaShader*>(brush);
	SkPaint paint;
	paint.setShader(shader->shader());
	// TODO(beng): set shader transform to match canvas transform.
	DrawRectInt(x, y, w, h, paint);
	}

	void CanvasSkia::DrawRectInt(const SkColor& color, int x, int y, int w, int h) {
	DrawRectInt(color, x, y, w, h, SkXfermode::kSrcOver_Mode);
	}

	void CanvasSkia::DrawRectInt(const SkColor& color,
	int x, int y, int w, int h,
	SkXfermode::Mode mode) {
	SkPaint paint;
	paint.setColor(color);
	paint.setStyle(SkPaint::kStroke_Style);
	// Set a stroke width of 0, which will put us down the stroke rect path. If
	// we set a stroke width of 1, for example, this will internally create a
	// path and fill it, which causes problems near the edge of the canvas.
	paint.setStrokeWidth(SkIntToScalar(0));
	paint.setXfermodeMode(mode);

	DrawRectInt(x, y, w, h, paint);
	}

	void CanvasSkia::DrawRectInt(int x, int y, int w, int h, const SkPaint& paint) {
	SkIRect rc = { x, y, x + w, y + h };
	drawIRect(rc, paint);
	}

	void CanvasSkia::DrawLineInt(const SkColor& color,
	int x1, int y1,
	int x2, int y2) {
	SkPaint paint;
	paint.setColor(color);
	paint.setStrokeWidth(SkIntToScalar(1));
	drawLine(SkIntToScalar(x1), SkIntToScalar(y1), SkIntToScalar(x2),
	SkIntToScalar(y2), paint);
	}

	void CanvasSkia::DrawFocusRect(int x, int y, int width, int height) {
	// Create a 2D bitmap containing alternating on/off pixels - we do this
	// so that you never get two pixels of the same color around the edges
	// of the focus rect (this may mean that opposing edges of the rect may
	// have a dot pattern out of phase to each other).
	static SkBitmap* dots = NULL;
	if (!dots) {
	int col_pixels = 32;
	int row_pixels = 32;

	dots = new SkBitmap;
	dots->setConfig(SkBitmap::kARGB_8888_Config, col_pixels, row_pixels);
	dots->allocPixels();
	dots->eraseARGB(0, 0, 0, 0);

	uint32_t* dot = dots->getAddr32(0, 0);
	for (int i = 0; i < row_pixels; i++) {
	for (int u = 0; u < col_pixels; u++) {
	if ((u % 2 + i % 2) % 2 != 0) {
	dot[i * row_pixels + u] = SK_ColorGRAY;
	}
	}
	}
	}

	// First the horizontal lines.

	// Make a shader for the bitmap with an origin of the box we'll draw. This
	// shader is refcounted and will have an initial refcount of 1.
	SkShader* shader = SkShader::CreateBitmapShader(
	*dots, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);
	// Assign the shader to the paint & release our reference. The paint will
	// now own the shader and the shader will be destroyed when the paint goes
	// out of scope.
	SkPaint paint;
	paint.setShader(shader);
	shader->unref();

	DrawRectInt(x, y, width, 1, paint);
	DrawRectInt(x, y + height - 1, width, 1, paint);
	DrawRectInt(x, y, 1, height, paint);
	DrawRectInt(x + width - 1, y, 1, height, paint);
	}

	void CanvasSkia::DrawBitmapInt(const SkBitmap& bitmap, int x, int y) {
	drawBitmap(bitmap, SkIntToScalar(x), SkIntToScalar(y));
	}

	void CanvasSkia::DrawBitmapInt(const SkBitmap& bitmap,
	int x, int y,
	const SkPaint& paint) {
	drawBitmap(bitmap, SkIntToScalar(x), SkIntToScalar(y), &paint);
	}

	void CanvasSkia::DrawBitmapInt(const SkBitmap& bitmap,
	int src_x, int src_y, int src_w, int src_h,
	int dest_x, int dest_y, int dest_w, int dest_h,
	bool filter) {
	SkPaint p;
	DrawBitmapInt(bitmap, src_x, src_y, src_w, src_h, dest_x, dest_y,
	dest_w, dest_h, filter, p);
	}

	void CanvasSkia::DrawBitmapInt(const SkBitmap& bitmap,
	int src_x, int src_y, int src_w, int src_h,
	int dest_x, int dest_y, int dest_w, int dest_h,
	bool filter,
	const SkPaint& paint) {
	DLOG_ASSERT(src_x + src_w < std::numeric_limits<int16_t>::max() &&
	src_y + src_h < std::numeric_limits<int16_t>::max());
	if (src_w <= 0 \|\| src_h <= 0 \|\| dest_w <= 0 \|\| dest_h <= 0) {
	NOTREACHED() << "Attempting to draw bitmap to/from an empty rect!";
	return;
	}

	if (!IntersectsClipRectInt(dest_x, dest_y, dest_w, dest_h))
	return;

	SkRect dest_rect = { SkIntToScalar(dest_x),
	SkIntToScalar(dest_y),
	SkIntToScalar(dest_x + dest_w),
	SkIntToScalar(dest_y + dest_h) };

	if (src_w == dest_w && src_h == dest_h) {
	// Workaround for apparent bug in Skia that causes image to occasionally
	// shift.
	SkIRect src_rect = { src_x, src_y, src_x + src_w, src_y + src_h };
	drawBitmapRect(bitmap, &src_rect, dest_rect, &paint);
	return;
	}

	// Make a bitmap shader that contains the bitmap we want to draw. This is
	// basically what SkCanvas.drawBitmap does internally, but it gives us
	// more control over quality and will use the mipmap in the source image if
	// it has one, whereas drawBitmap won't.
	SkShader* shader = SkShader::CreateBitmapShader(bitmap,
	SkShader::kRepeat_TileMode,
	SkShader::kRepeat_TileMode);
	SkMatrix shader_scale;
	shader_scale.setScale(SkFloatToScalar(static_cast<float>(dest_w) / src_w),
	SkFloatToScalar(static_cast<float>(dest_h) / src_h));
	shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
	shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));
	shader->setLocalMatrix(shader_scale);

	// Set up our paint to use the shader & release our reference (now just owned
	// by the paint).
	SkPaint p(paint);
	p.setFilterBitmap(filter);
	p.setShader(shader);
	shader->unref();

	// The rect will be filled by the bitmap.
	drawRect(dest_rect, p);
	}

	void CanvasSkia::DrawStringInt(const std::wstring& text,
	const gfx::Font& font,
	const SkColor& color,
	int x, int y, int w, int h) {
	DrawStringInt(text, font, color, x, y, w, h,
	gfx::CanvasSkia::DefaultCanvasTextAlignment());
	}

	void CanvasSkia::DrawStringInt(const std::wstring& text,
	const gfx::Font& font,
	const SkColor& color,
	const gfx::Rect& display_rect) {
	DrawStringInt(text, font, color, display_rect.x(), display_rect.y(),
	display_rect.width(), display_rect.height());
	}

	void CanvasSkia::TileImageInt(const SkBitmap& bitmap,
	int x, int y, int w, int h) {
	TileImageInt(bitmap, 0, 0, x, y, w, h);
	}

	void CanvasSkia::TileImageInt(const SkBitmap& bitmap,
	int src_x, int src_y,
	int dest_x, int dest_y, int w, int h) {
	if (!IntersectsClipRectInt(dest_x, dest_y, w, h))
	return;

	SkPaint paint;

	SkShader* shader = SkShader::CreateBitmapShader(bitmap,
	SkShader::kRepeat_TileMode,
	SkShader::kRepeat_TileMode);
	paint.setShader(shader);
	paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);

	// CreateBitmapShader returns a Shader with a reference count of one, we
	// need to unref after paint takes ownership of the shader.
	shader->unref();
	save();
	translate(SkIntToScalar(dest_x - src_x), SkIntToScalar(dest_y - src_y));
	ClipRectInt(src_x, src_y, w, h);
	drawPaint(paint);
	restore();
	}

	gfx::NativeDrawingContext CanvasSkia::BeginPlatformPaint() {
	return beginPlatformPaint();
	}

	void CanvasSkia::EndPlatformPaint() {
	endPlatformPaint();
	}

	CanvasSkia* CanvasSkia::AsCanvasSkia() {
	return this;
	}

	const CanvasSkia* CanvasSkia::AsCanvasSkia() const {
	return this;
	}

	////////////////////////////////////////////////////////////////////////////////
	// CanvasSkia, private:

	bool CanvasSkia::IntersectsClipRectInt(int x, int y, int w, int h) {
	SkRect clip;
	return getClipBounds(&clip) &&
	clip.intersect(SkIntToScalar(x), SkIntToScalar(y), SkIntToScalar(x + w),
	SkIntToScalar(y + h));
	}

	////////////////////////////////////////////////////////////////////////////////
	// Canvas, public:

	Canvas* Canvas::CreateCanvas() {
	return new CanvasSkia;
	}

	Canvas* Canvas::CreateCanvas(int width, int height, bool is_opaque) {
	return new CanvasSkia(width, height, is_opaque);
	}

	#if defined(OS_WIN)
	// TODO(beng): move to canvas_win.cc, etc.
	class CanvasPaintWin : public CanvasSkiaPaint, public CanvasPaint {
	public:
	CanvasPaintWin(gfx::NativeView view) : CanvasSkiaPaint(view) {}

	// Overridden from CanvasPaint2:
	virtual bool IsValid() const {
	return isEmpty();
	}

	virtual gfx::Rect GetInvalidRect() const {
	return gfx::Rect(paintStruct().rcPaint);
	}

	virtual Canvas* AsCanvas() {
	return this;
	}
	};
	#endif

	CanvasPaint* CanvasPaint::CreateCanvasPaint(gfx::NativeView view) {
	#if defined(OS_WIN)
	return new CanvasPaintWin(view);
	#else
	return NULL;
	#endif
	}

	} // namespace gfx