ui/gfx/canvas.cc - git/chromium - Git at Google

 // 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.

 #include "ui/gfx/canvas.h"

 #include <limits>

 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/skia_util.h"
 #include "ui/gfx/transform.h"

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

 namespace gfx {

 Canvas::Canvas(const gfx::Size& size,
                ui::ScaleFactor scale_factor,
                bool is_opaque)
       : scale_factor_(scale_factor),
         owned_canvas_(NULL),
         canvas_(NULL) {
   gfx::Size pixel_size = size.Scale(ui::GetScaleFactorScale(scale_factor));
   owned_canvas_.reset(new skia::PlatformCanvas(pixel_size.width(),
                                                pixel_size.height(),
                                                is_opaque));
   canvas_ = owned_canvas_.get();
 #if defined(OS_WIN) || defined(OS_MACOSX)
   // skia::PlatformCanvas instances are initialized to 0 by Cairo on Linux, but
   // uninitialized on Win and Mac.
   if (!is_opaque)
     owned_canvas_->clear(SkColorSetARGB(0, 0, 0, 0));
 #endif

   SkScalar scale = SkFloatToScalar(ui::GetScaleFactorScale(scale_factor));
   canvas_->scale(scale, scale);
 }

 Canvas::Canvas(const gfx::ImageSkiaRep& image_rep, bool is_opaque)
     : scale_factor_(image_rep.scale_factor()),
       owned_canvas_(new skia::PlatformCanvas(image_rep.pixel_width(),
                                              image_rep.pixel_height(),
                                              is_opaque)),
       canvas_(owned_canvas_.get()) {
   SkScalar scale = SkFloatToScalar(ui::GetScaleFactorScale(scale_factor_));
   canvas_->scale(scale, scale);
   DrawImageInt(gfx::ImageSkia(image_rep), 0, 0);
 }

 Canvas::Canvas()
     : scale_factor_(ui::SCALE_FACTOR_100P),
       owned_canvas_(new skia::PlatformCanvas()),
       canvas_(owned_canvas_.get()) {
 }

 Canvas::~Canvas() {
 }

 // static
 Canvas* Canvas::CreateCanvasWithoutScaling(SkCanvas* canvas,
                                            ui::ScaleFactor scale_factor) {
   return new Canvas(canvas, scale_factor);
 }

 void Canvas::RecreateBackingCanvas(const gfx::Size& size,
                                    ui::ScaleFactor scale_factor,
                                    bool is_opaque) {
   scale_factor_ = scale_factor;
   gfx::Size pixel_size = size.Scale(ui::GetScaleFactorScale(scale_factor));
   owned_canvas_.reset(new skia::PlatformCanvas(pixel_size.width(),
                                                pixel_size.height(),
                                                is_opaque));
   canvas_ = owned_canvas_.get();
   SkScalar scale = SkFloatToScalar(ui::GetScaleFactorScale(scale_factor_));
   canvas_->scale(scale, scale);
 }

 // static
 int Canvas::GetStringWidth(const string16& text, const gfx::Font& font) {
   int width = 0, height = 0;
   Canvas::SizeStringInt(text, font, &width, &height, NO_ELLIPSIS);
   return width;
 }

 // static
 int Canvas::DefaultCanvasTextAlignment() {
   return base::i18n::IsRTL() ? TEXT_ALIGN_RIGHT : TEXT_ALIGN_LEFT;
 }

 gfx::ImageSkiaRep Canvas::ExtractImageRep() const {
   const SkBitmap& device_bitmap = canvas_->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 gfx::ImageSkiaRep(result, scale_factor_);
 }

 void Canvas::DrawDashedRect(const gfx::Rect& rect, SkColor color) {
   // 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 SkColor last_color;
   static SkBitmap* dots = NULL;
   if (!dots || last_color != color) {
     int col_pixels = 32;
     int row_pixels = 32;

     delete dots;
     last_color = color;
     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] = color;
         }
       }
     }
   }

   // 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();

   DrawRect(gfx::Rect(rect.x(), rect.y(), rect.width(), 1), paint);
   DrawRect(gfx::Rect(rect.x(), rect.y() + rect.height() - 1, rect.width(), 1),
            paint);
   DrawRect(gfx::Rect(rect.x(), rect.y(), 1, rect.height()), paint);
   DrawRect(gfx::Rect(rect.x() + rect.width() - 1, rect.y(), 1, rect.height()),
            paint);
 }

 void Canvas::Save() {
   canvas_->save();
 }

 void Canvas::SaveLayerAlpha(uint8 alpha) {
   canvas_->saveLayerAlpha(NULL, alpha);
 }


 void Canvas::SaveLayerAlpha(uint8 alpha, const gfx::Rect& layer_bounds) {
   SkRect bounds(gfx::RectToSkRect(layer_bounds));
   canvas_->saveLayerAlpha(&bounds, alpha);
 }

 void Canvas::Restore() {
   canvas_->restore();
 }

 bool Canvas::ClipRect(const gfx::Rect& rect) {
   return canvas_->clipRect(gfx::RectToSkRect(rect));
 }

 bool Canvas::ClipPath(const SkPath& path) {
   return canvas_->clipPath(path);
 }

 bool Canvas::GetClipBounds(gfx::Rect* bounds) {
   SkRect out;
   bool has_non_empty_clip = canvas_->getClipBounds(&out);
   bounds->SetRect(out.left(), out.top(), out.width(), out.height());
   return has_non_empty_clip;
 }

 void Canvas::Translate(const gfx::Point& point) {
   canvas_->translate(SkIntToScalar(point.x()), SkIntToScalar(point.y()));
 }

 void Canvas::Scale(int x_scale, int y_scale) {
   canvas_->scale(SkIntToScalar(x_scale), SkIntToScalar(y_scale));
 }

 void Canvas::DrawColor(SkColor color) {
   DrawColor(color, SkXfermode::kSrcOver_Mode);
 }

 void Canvas::DrawColor(SkColor color, SkXfermode::Mode mode) {
   canvas_->drawColor(color, mode);
 }

 void Canvas::FillRect(const gfx::Rect& rect, SkColor color) {
   FillRect(rect, color, SkXfermode::kSrcOver_Mode);
 }

 void Canvas::FillRect(const gfx::Rect& rect,
                       SkColor color,
                       SkXfermode::Mode mode) {
   SkPaint paint;
   paint.setColor(color);
   paint.setStyle(SkPaint::kFill_Style);
   paint.setXfermodeMode(mode);
   DrawRect(rect, paint);
 }

 void Canvas::DrawRect(const gfx::Rect& rect, SkColor color) {
   DrawRect(rect, color, SkXfermode::kSrcOver_Mode);
 }

 void Canvas::DrawRect(const gfx::Rect& rect,
                       SkColor color,
                       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);

   DrawRect(rect, paint);
 }

 void Canvas::DrawRect(const gfx::Rect& rect, const SkPaint& paint) {
   canvas_->drawIRect(RectToSkIRect(rect), paint);
 }

 void Canvas::DrawPoint(const gfx::Point& p1, const SkPaint& paint) {
   canvas_->drawPoint(SkIntToScalar(p1.x()), SkIntToScalar(p1.y()), paint);
 }

 void Canvas::DrawLine(const gfx::Point& p1,
                       const gfx::Point& p2,
                       SkColor color) {
   SkPaint paint;
   paint.setColor(color);
   paint.setStrokeWidth(SkIntToScalar(1));
   DrawLine(p1, p2, paint);
 }

 void Canvas::DrawLine(const gfx::Point& p1,
                       const gfx::Point& p2,
                       const SkPaint& paint) {
   canvas_->drawLine(SkIntToScalar(p1.x()), SkIntToScalar(p1.y()),
                     SkIntToScalar(p2.x()), SkIntToScalar(p2.y()), paint);
 }

 void Canvas::DrawCircle(const gfx::Point& center_point,
                         int radius,
                         const SkPaint& paint) {
   canvas_->drawCircle(SkIntToScalar(center_point.x()),
       SkIntToScalar(center_point.y()), SkIntToScalar(radius), paint);
 }

 void Canvas::DrawRoundRect(const gfx::Rect& rect,
                            int radius,
                            const SkPaint& paint) {
   canvas_->drawRoundRect(RectToSkRect(rect), SkIntToScalar(radius),
                          SkIntToScalar(radius), paint);
 }

 void Canvas::DrawPath(const SkPath& path, const SkPaint& paint) {
   canvas_->drawPath(path, paint);
 }

 void Canvas::DrawFocusRect(const gfx::Rect& rect) {
   DrawDashedRect(rect, SK_ColorGRAY);
 }

 void Canvas::DrawImageInt(const gfx::ImageSkia& image, int x, int y) {
   SkPaint paint;
   DrawImageInt(image, x, y, paint);
 }

 void Canvas::DrawImageInt(const gfx::ImageSkia& image,
                           int x, int y,
                           const SkPaint& paint) {
   const gfx::ImageSkiaRep& image_rep = GetImageRepToPaint(image);
   if (image_rep.is_null())
     return;
   const SkBitmap& bitmap = image_rep.sk_bitmap();
   float bitmap_scale = image_rep.GetScale();

   canvas_->save();
   canvas_->scale(SkFloatToScalar(1.0f / bitmap_scale),
                  SkFloatToScalar(1.0f / bitmap_scale));
   canvas_->drawBitmap(bitmap,
                       SkFloatToScalar(x * bitmap_scale),
                       SkFloatToScalar(y * bitmap_scale),
                       &paint);
   canvas_->restore();
 }

 void Canvas::DrawImageInt(const gfx::ImageSkia& image,
                           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;
   DrawImageInt(image, src_x, src_y, src_w, src_h, dest_x, dest_y,
                dest_w, dest_h, filter, p);
 }

 void Canvas::DrawImageInt(const gfx::ImageSkia& image,
                           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) {
     NOTREACHED() << "Attempting to draw bitmap from an empty rect!";
     return;
   }

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

   float user_scale_x = static_cast<float>(dest_w) / src_w;
   float user_scale_y = static_cast<float>(dest_h) / src_h;

   const gfx::ImageSkiaRep& image_rep = GetImageRepToPaint(image,
       user_scale_x, user_scale_y);
   if (image_rep.is_null())
     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 &&
       user_scale_x == 1.0f && user_scale_y == 1.0f &&
       image_rep.scale_factor() == ui::SCALE_FACTOR_100P) {
     // 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 };
     const SkBitmap& bitmap = image_rep.sk_bitmap();
     canvas_->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.
   SkMatrix shader_scale;
   shader_scale.setScale(SkFloatToScalar(user_scale_x),
                         SkFloatToScalar(user_scale_y));
   shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
   shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));

   SkShader* shader = gfx::CreateImageRepShader(image_rep,
                                                SkShader::kRepeat_TileMode,
                                                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.
   canvas_->drawRect(dest_rect, p);
 }

 void Canvas::DrawImageInPath(const gfx::ImageSkia& image,
                              int x,
                              int y,
                              const SkPath& path,
                              const SkPaint& paint) {
   const gfx::ImageSkiaRep& image_rep = GetImageRepToPaint(image);
   if (image_rep.is_null())
     return;

   SkMatrix matrix;
   matrix.setTranslate(SkIntToScalar(x), SkIntToScalar(y));
   SkShader* shader = gfx::CreateImageRepShader(image_rep,
       SkShader::kRepeat_TileMode, matrix);

   SkPaint p(paint);
   p.setShader(shader);
   shader->unref();
   canvas_->drawPath(path, p);
 }

 void Canvas::DrawStringInt(const string16& text,
                            const gfx::Font& font,
                            SkColor color,
                            int x, int y, int w, int h) {
   DrawStringInt(text, font, color, x, y, w, h, DefaultCanvasTextAlignment());
 }

 void Canvas::DrawStringInt(const string16& text,
                            const gfx::Font& font,
                            SkColor color,
                            const gfx::Rect& display_rect) {
   DrawStringInt(text, font, color, display_rect.x(), display_rect.y(),
                 display_rect.width(), display_rect.height());
 }

 void Canvas::DrawStringInt(const string16& text,
                            const gfx::Font& font,
                            SkColor color,
                            int x, int y, int w, int h,
                            int flags) {
   DrawStringWithShadows(text,
                         font,
                         color,
                         gfx::Rect(x, y, w, h),
                         flags,
                         ShadowValues());
 }

 void Canvas::TileImageInt(const gfx::ImageSkia& image,
                           int x, int y, int w, int h) {
   TileImageInt(image, 0, 0, x, y, w, h);
 }

 void Canvas::TileImageInt(const gfx::ImageSkia& image,
                           int src_x, int src_y,
                           int dest_x, int dest_y, int w, int h) {
   TileImageInt(image, src_x, src_y, 1.0f, 1.0f, dest_x, dest_y, w, h);
 }

 void Canvas::TileImageInt(const gfx::ImageSkia& image,
                           int src_x, int src_y,
                           float tile_scale_x, float tile_scale_y,
                           int dest_x, int dest_y, int w, int h) {
   if (!IntersectsClipRectInt(dest_x, dest_y, w, h))
     return;

   const gfx::ImageSkiaRep& image_rep = GetImageRepToPaint(image,
       tile_scale_x, tile_scale_y);
   if (image_rep.is_null())
     return;

   SkMatrix shader_scale;
   shader_scale.setScale(SkFloatToScalar(tile_scale_x),
                         SkFloatToScalar(tile_scale_y));
   shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
   shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));

   SkShader* shader = gfx::CreateImageRepShader(image_rep,
                                                SkShader::kRepeat_TileMode,
                                                shader_scale);

   SkPaint paint;
   paint.setShader(shader);
   paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
   shader->unref();

   SkRect dest_rect = { SkIntToScalar(dest_x),
                        SkIntToScalar(dest_y),
                        SkIntToScalar(dest_x + w),
                        SkIntToScalar(dest_y + h) };
   canvas_->drawRect(dest_rect, paint);
 }

 gfx::NativeDrawingContext Canvas::BeginPlatformPaint() {
   return skia::BeginPlatformPaint(canvas_);
 }

 void Canvas::EndPlatformPaint() {
   skia::EndPlatformPaint(canvas_);
 }

 void Canvas::Transform(const ui::Transform& transform) {
   canvas_->concat(transform.matrix());
 }

 Canvas::Canvas(SkCanvas* canvas, ui::ScaleFactor scale_factor)
     : scale_factor_(scale_factor),
       owned_canvas_(),
       canvas_(canvas) {
   DCHECK(canvas);
 }

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

 bool Canvas::IntersectsClipRect(const gfx::Rect& rect) {
   return IntersectsClipRectInt(rect.x(), rect.y(),
                                rect.width(), rect.height());
 }

 const gfx::ImageSkiaRep& Canvas::GetImageRepToPaint(
     const gfx::ImageSkia& image) const {
   return GetImageRepToPaint(image, 1.0f, 1.0f);
 }

 const gfx::ImageSkiaRep& Canvas::GetImageRepToPaint(
     const gfx::ImageSkia& image,
     float user_additional_scale_x,
     float user_additional_scale_y) const {
   const gfx::ImageSkiaRep& image_rep = image.GetRepresentation(scale_factor_);

   if (!image_rep.is_null()) {
     SkMatrix m = canvas_->getTotalMatrix();
     float scale_x = SkScalarToFloat(SkScalarAbs(m.getScaleX())) *
         user_additional_scale_x;
     float scale_y = SkScalarToFloat(SkScalarAbs(m.getScaleY())) *
         user_additional_scale_y;

     float bitmap_scale = image_rep.GetScale();
     if (scale_x < bitmap_scale || scale_y < bitmap_scale)
       const_cast<SkBitmap&>(image_rep.sk_bitmap()).buildMipMap();
   }

   return image_rep;
 }

 }  // namespace gfx
	// 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.

	#include "ui/gfx/canvas.h"

	#include <limits>

	#include "base/i18n/rtl.h"
	#include "base/logging.h"
	#include "third_party/skia/include/core/SkBitmap.h"
	#include "third_party/skia/include/effects/SkGradientShader.h"
	#include "ui/gfx/canvas.h"
	#include "ui/gfx/font.h"
	#include "ui/gfx/rect.h"
	#include "ui/gfx/skia_util.h"
	#include "ui/gfx/transform.h"

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

	namespace gfx {

	Canvas::Canvas(const gfx::Size& size,
	ui::ScaleFactor scale_factor,
	bool is_opaque)
	: scale_factor_(scale_factor),
	owned_canvas_(NULL),
	canvas_(NULL) {
	gfx::Size pixel_size = size.Scale(ui::GetScaleFactorScale(scale_factor));
	owned_canvas_.reset(new skia::PlatformCanvas(pixel_size.width(),
	pixel_size.height(),
	is_opaque));
	canvas_ = owned_canvas_.get();
	#if defined(OS_WIN) \|\| defined(OS_MACOSX)
	// skia::PlatformCanvas instances are initialized to 0 by Cairo on Linux, but
	// uninitialized on Win and Mac.
	if (!is_opaque)
	owned_canvas_->clear(SkColorSetARGB(0, 0, 0, 0));
	#endif

	SkScalar scale = SkFloatToScalar(ui::GetScaleFactorScale(scale_factor));
	canvas_->scale(scale, scale);
	}

	Canvas::Canvas(const gfx::ImageSkiaRep& image_rep, bool is_opaque)
	: scale_factor_(image_rep.scale_factor()),
	owned_canvas_(new skia::PlatformCanvas(image_rep.pixel_width(),
	image_rep.pixel_height(),
	is_opaque)),
	canvas_(owned_canvas_.get()) {
	SkScalar scale = SkFloatToScalar(ui::GetScaleFactorScale(scale_factor_));
	canvas_->scale(scale, scale);
	DrawImageInt(gfx::ImageSkia(image_rep), 0, 0);
	}

	Canvas::Canvas()
	: scale_factor_(ui::SCALE_FACTOR_100P),
	owned_canvas_(new skia::PlatformCanvas()),
	canvas_(owned_canvas_.get()) {
	}

	Canvas::~Canvas() {
	}

	// static
	Canvas* Canvas::CreateCanvasWithoutScaling(SkCanvas* canvas,
	ui::ScaleFactor scale_factor) {
	return new Canvas(canvas, scale_factor);
	}

	void Canvas::RecreateBackingCanvas(const gfx::Size& size,
	ui::ScaleFactor scale_factor,
	bool is_opaque) {
	scale_factor_ = scale_factor;
	gfx::Size pixel_size = size.Scale(ui::GetScaleFactorScale(scale_factor));
	owned_canvas_.reset(new skia::PlatformCanvas(pixel_size.width(),
	pixel_size.height(),
	is_opaque));
	canvas_ = owned_canvas_.get();
	SkScalar scale = SkFloatToScalar(ui::GetScaleFactorScale(scale_factor_));
	canvas_->scale(scale, scale);
	}

	// static
	int Canvas::GetStringWidth(const string16& text, const gfx::Font& font) {
	int width = 0, height = 0;
	Canvas::SizeStringInt(text, font, &width, &height, NO_ELLIPSIS);
	return width;
	}

	// static
	int Canvas::DefaultCanvasTextAlignment() {
	return base::i18n::IsRTL() ? TEXT_ALIGN_RIGHT : TEXT_ALIGN_LEFT;
	}

	gfx::ImageSkiaRep Canvas::ExtractImageRep() const {
	const SkBitmap& device_bitmap = canvas_->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 gfx::ImageSkiaRep(result, scale_factor_);
	}

	void Canvas::DrawDashedRect(const gfx::Rect& rect, SkColor color) {
	// 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 SkColor last_color;
	static SkBitmap* dots = NULL;
	if (!dots \|\| last_color != color) {
	int col_pixels = 32;
	int row_pixels = 32;

	delete dots;
	last_color = color;
	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] = color;
	}
	}
	}
	}

	// 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();

	DrawRect(gfx::Rect(rect.x(), rect.y(), rect.width(), 1), paint);
	DrawRect(gfx::Rect(rect.x(), rect.y() + rect.height() - 1, rect.width(), 1),
	paint);
	DrawRect(gfx::Rect(rect.x(), rect.y(), 1, rect.height()), paint);
	DrawRect(gfx::Rect(rect.x() + rect.width() - 1, rect.y(), 1, rect.height()),
	paint);
	}

	void Canvas::Save() {
	canvas_->save();
	}

	void Canvas::SaveLayerAlpha(uint8 alpha) {
	canvas_->saveLayerAlpha(NULL, alpha);
	}


	void Canvas::SaveLayerAlpha(uint8 alpha, const gfx::Rect& layer_bounds) {
	SkRect bounds(gfx::RectToSkRect(layer_bounds));
	canvas_->saveLayerAlpha(&bounds, alpha);
	}

	void Canvas::Restore() {
	canvas_->restore();
	}

	bool Canvas::ClipRect(const gfx::Rect& rect) {
	return canvas_->clipRect(gfx::RectToSkRect(rect));
	}

	bool Canvas::ClipPath(const SkPath& path) {
	return canvas_->clipPath(path);
	}

	bool Canvas::GetClipBounds(gfx::Rect* bounds) {
	SkRect out;
	bool has_non_empty_clip = canvas_->getClipBounds(&out);
	bounds->SetRect(out.left(), out.top(), out.width(), out.height());
	return has_non_empty_clip;
	}

	void Canvas::Translate(const gfx::Point& point) {
	canvas_->translate(SkIntToScalar(point.x()), SkIntToScalar(point.y()));
	}

	void Canvas::Scale(int x_scale, int y_scale) {
	canvas_->scale(SkIntToScalar(x_scale), SkIntToScalar(y_scale));
	}

	void Canvas::DrawColor(SkColor color) {
	DrawColor(color, SkXfermode::kSrcOver_Mode);
	}

	void Canvas::DrawColor(SkColor color, SkXfermode::Mode mode) {
	canvas_->drawColor(color, mode);
	}

	void Canvas::FillRect(const gfx::Rect& rect, SkColor color) {
	FillRect(rect, color, SkXfermode::kSrcOver_Mode);
	}

	void Canvas::FillRect(const gfx::Rect& rect,
	SkColor color,
	SkXfermode::Mode mode) {
	SkPaint paint;
	paint.setColor(color);
	paint.setStyle(SkPaint::kFill_Style);
	paint.setXfermodeMode(mode);
	DrawRect(rect, paint);
	}

	void Canvas::DrawRect(const gfx::Rect& rect, SkColor color) {
	DrawRect(rect, color, SkXfermode::kSrcOver_Mode);
	}

	void Canvas::DrawRect(const gfx::Rect& rect,
	SkColor color,
	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);

	DrawRect(rect, paint);
	}

	void Canvas::DrawRect(const gfx::Rect& rect, const SkPaint& paint) {
	canvas_->drawIRect(RectToSkIRect(rect), paint);
	}

	void Canvas::DrawPoint(const gfx::Point& p1, const SkPaint& paint) {
	canvas_->drawPoint(SkIntToScalar(p1.x()), SkIntToScalar(p1.y()), paint);
	}

	void Canvas::DrawLine(const gfx::Point& p1,
	const gfx::Point& p2,
	SkColor color) {
	SkPaint paint;
	paint.setColor(color);
	paint.setStrokeWidth(SkIntToScalar(1));
	DrawLine(p1, p2, paint);
	}

	void Canvas::DrawLine(const gfx::Point& p1,
	const gfx::Point& p2,
	const SkPaint& paint) {
	canvas_->drawLine(SkIntToScalar(p1.x()), SkIntToScalar(p1.y()),
	SkIntToScalar(p2.x()), SkIntToScalar(p2.y()), paint);
	}

	void Canvas::DrawCircle(const gfx::Point& center_point,
	int radius,
	const SkPaint& paint) {
	canvas_->drawCircle(SkIntToScalar(center_point.x()),
	SkIntToScalar(center_point.y()), SkIntToScalar(radius), paint);
	}

	void Canvas::DrawRoundRect(const gfx::Rect& rect,
	int radius,
	const SkPaint& paint) {
	canvas_->drawRoundRect(RectToSkRect(rect), SkIntToScalar(radius),
	SkIntToScalar(radius), paint);
	}

	void Canvas::DrawPath(const SkPath& path, const SkPaint& paint) {
	canvas_->drawPath(path, paint);
	}

	void Canvas::DrawFocusRect(const gfx::Rect& rect) {
	DrawDashedRect(rect, SK_ColorGRAY);
	}

	void Canvas::DrawImageInt(const gfx::ImageSkia& image, int x, int y) {
	SkPaint paint;
	DrawImageInt(image, x, y, paint);
	}

	void Canvas::DrawImageInt(const gfx::ImageSkia& image,
	int x, int y,
	const SkPaint& paint) {
	const gfx::ImageSkiaRep& image_rep = GetImageRepToPaint(image);
	if (image_rep.is_null())
	return;
	const SkBitmap& bitmap = image_rep.sk_bitmap();
	float bitmap_scale = image_rep.GetScale();

	canvas_->save();
	canvas_->scale(SkFloatToScalar(1.0f / bitmap_scale),
	SkFloatToScalar(1.0f / bitmap_scale));
	canvas_->drawBitmap(bitmap,
	SkFloatToScalar(x * bitmap_scale),
	SkFloatToScalar(y * bitmap_scale),
	&paint);
	canvas_->restore();
	}

	void Canvas::DrawImageInt(const gfx::ImageSkia& image,
	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;
	DrawImageInt(image, src_x, src_y, src_w, src_h, dest_x, dest_y,
	dest_w, dest_h, filter, p);
	}

	void Canvas::DrawImageInt(const gfx::ImageSkia& image,
	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) {
	NOTREACHED() << "Attempting to draw bitmap from an empty rect!";
	return;
	}

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

	float user_scale_x = static_cast<float>(dest_w) / src_w;
	float user_scale_y = static_cast<float>(dest_h) / src_h;

	const gfx::ImageSkiaRep& image_rep = GetImageRepToPaint(image,
	user_scale_x, user_scale_y);
	if (image_rep.is_null())
	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 &&
	user_scale_x == 1.0f && user_scale_y == 1.0f &&
	image_rep.scale_factor() == ui::SCALE_FACTOR_100P) {
	// 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 };
	const SkBitmap& bitmap = image_rep.sk_bitmap();
	canvas_->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.
	SkMatrix shader_scale;
	shader_scale.setScale(SkFloatToScalar(user_scale_x),
	SkFloatToScalar(user_scale_y));
	shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
	shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));

	SkShader* shader = gfx::CreateImageRepShader(image_rep,
	SkShader::kRepeat_TileMode,
	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.
	canvas_->drawRect(dest_rect, p);
	}

	void Canvas::DrawImageInPath(const gfx::ImageSkia& image,
	int x,
	int y,
	const SkPath& path,
	const SkPaint& paint) {
	const gfx::ImageSkiaRep& image_rep = GetImageRepToPaint(image);
	if (image_rep.is_null())
	return;

	SkMatrix matrix;
	matrix.setTranslate(SkIntToScalar(x), SkIntToScalar(y));
	SkShader* shader = gfx::CreateImageRepShader(image_rep,
	SkShader::kRepeat_TileMode, matrix);

	SkPaint p(paint);
	p.setShader(shader);
	shader->unref();
	canvas_->drawPath(path, p);
	}

	void Canvas::DrawStringInt(const string16& text,
	const gfx::Font& font,
	SkColor color,
	int x, int y, int w, int h) {
	DrawStringInt(text, font, color, x, y, w, h, DefaultCanvasTextAlignment());
	}

	void Canvas::DrawStringInt(const string16& text,
	const gfx::Font& font,
	SkColor color,
	const gfx::Rect& display_rect) {
	DrawStringInt(text, font, color, display_rect.x(), display_rect.y(),
	display_rect.width(), display_rect.height());
	}

	void Canvas::DrawStringInt(const string16& text,
	const gfx::Font& font,
	SkColor color,
	int x, int y, int w, int h,
	int flags) {
	DrawStringWithShadows(text,
	font,
	color,
	gfx::Rect(x, y, w, h),
	flags,
	ShadowValues());
	}

	void Canvas::TileImageInt(const gfx::ImageSkia& image,
	int x, int y, int w, int h) {
	TileImageInt(image, 0, 0, x, y, w, h);
	}

	void Canvas::TileImageInt(const gfx::ImageSkia& image,
	int src_x, int src_y,
	int dest_x, int dest_y, int w, int h) {
	TileImageInt(image, src_x, src_y, 1.0f, 1.0f, dest_x, dest_y, w, h);
	}

	void Canvas::TileImageInt(const gfx::ImageSkia& image,
	int src_x, int src_y,
	float tile_scale_x, float tile_scale_y,
	int dest_x, int dest_y, int w, int h) {
	if (!IntersectsClipRectInt(dest_x, dest_y, w, h))
	return;

	const gfx::ImageSkiaRep& image_rep = GetImageRepToPaint(image,
	tile_scale_x, tile_scale_y);
	if (image_rep.is_null())
	return;

	SkMatrix shader_scale;
	shader_scale.setScale(SkFloatToScalar(tile_scale_x),
	SkFloatToScalar(tile_scale_y));
	shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
	shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));

	SkShader* shader = gfx::CreateImageRepShader(image_rep,
	SkShader::kRepeat_TileMode,
	shader_scale);

	SkPaint paint;
	paint.setShader(shader);
	paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
	shader->unref();

	SkRect dest_rect = { SkIntToScalar(dest_x),
	SkIntToScalar(dest_y),
	SkIntToScalar(dest_x + w),
	SkIntToScalar(dest_y + h) };
	canvas_->drawRect(dest_rect, paint);
	}

	gfx::NativeDrawingContext Canvas::BeginPlatformPaint() {
	return skia::BeginPlatformPaint(canvas_);
	}

	void Canvas::EndPlatformPaint() {
	skia::EndPlatformPaint(canvas_);
	}

	void Canvas::Transform(const ui::Transform& transform) {
	canvas_->concat(transform.matrix());
	}

	Canvas::Canvas(SkCanvas* canvas, ui::ScaleFactor scale_factor)
	: scale_factor_(scale_factor),
	owned_canvas_(),
	canvas_(canvas) {
	DCHECK(canvas);
	}

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

	bool Canvas::IntersectsClipRect(const gfx::Rect& rect) {
	return IntersectsClipRectInt(rect.x(), rect.y(),
	rect.width(), rect.height());
	}

	const gfx::ImageSkiaRep& Canvas::GetImageRepToPaint(
	const gfx::ImageSkia& image) const {
	return GetImageRepToPaint(image, 1.0f, 1.0f);
	}

	const gfx::ImageSkiaRep& Canvas::GetImageRepToPaint(
	const gfx::ImageSkia& image,
	float user_additional_scale_x,
	float user_additional_scale_y) const {
	const gfx::ImageSkiaRep& image_rep = image.GetRepresentation(scale_factor_);

	if (!image_rep.is_null()) {
	SkMatrix m = canvas_->getTotalMatrix();
	float scale_x = SkScalarToFloat(SkScalarAbs(m.getScaleX())) *
	user_additional_scale_x;
	float scale_y = SkScalarToFloat(SkScalarAbs(m.getScaleY())) *
	user_additional_scale_y;

	float bitmap_scale = image_rep.GetScale();
	if (scale_x < bitmap_scale \|\| scale_y < bitmap_scale)
	const_cast<SkBitmap&>(image_rep.sk_bitmap()).buildMipMap();
	}

	return image_rep;
	}

	} // namespace gfx