ui/gfx/canvas.cc

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This source file includes following definitions.
canvas_
canvas_
canvas_
CreateCanvasWithoutScaling
RecreateBackingCanvas
SizeStringInt
GetStringWidth
GetStringWidthF
DefaultCanvasTextAlignment
ExtractImageRep
DrawDashedRect
Save
SaveLayerAlpha
SaveLayerAlpha
Restore
ClipRect
ClipPath
IsClipEmpty
GetClipBounds
Translate
Scale
DrawColor
DrawColor
FillRect
FillRect
DrawRect
DrawRect
DrawRect
DrawPoint
DrawLine
DrawLine
DrawCircle
DrawRoundRect
DrawPath
DrawFocusRect
DrawSolidFocusRect
DrawImageInt
DrawImageInt
DrawImageInt
DrawImageInt
DrawImageInt
DrawImageInPath
DrawStringRect
DrawStringRectWithFlags
TileImageInt
TileImageInt
TileImageInt
BeginPlatformPaint
EndPlatformPaint
Transform
canvas_
IntersectsClipRectInt
IntersectsClipRect
GetImageRepToPaint
GetImageRepToPaint
// 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 <cmath>
#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/font_list.h"
#include "ui/gfx/rect.h"
#include "ui/gfx/size_conversions.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 Size& size, float image_scale, bool is_opaque)
    : image_scale_(image_scale),
      canvas_(NULL) {
  Size pixel_size = ToCeiledSize(ScaleSize(size, image_scale));
  owned_canvas_ = skia::AdoptRef(skia::CreatePlatformCanvas(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_scalar = SkFloatToScalar(image_scale);
  canvas_->scale(scale_scalar, scale_scalar);
}

Canvas::Canvas(const ImageSkiaRep& image_rep, bool is_opaque)
    : image_scale_(image_rep.scale()),
      owned_canvas_(skia::AdoptRef(
          skia::CreatePlatformCanvas(image_rep.pixel_width(),
                                     image_rep.pixel_height(),
                                     is_opaque))),
      canvas_(owned_canvas_.get()) {
  SkScalar scale_scalar = SkFloatToScalar(image_scale_);
  canvas_->scale(scale_scalar, scale_scalar);
  DrawImageInt(ImageSkia(image_rep), 0, 0);
}

Canvas::Canvas()
    : image_scale_(1.0),
      owned_canvas_(skia::AdoptRef(skia::CreatePlatformCanvas(0, 0, false))),
      canvas_(owned_canvas_.get()) {
}

Canvas::~Canvas() {
}

// static
Canvas* Canvas::CreateCanvasWithoutScaling(SkCanvas* canvas,
                                           float image_scale) {
  return new Canvas(canvas, image_scale);
}

void Canvas::RecreateBackingCanvas(const Size& size,
                                   float image_scale,
                                   bool is_opaque) {
  image_scale_ = image_scale;
  Size pixel_size = ToFlooredSize(ScaleSize(size, image_scale));
  owned_canvas_ = skia::AdoptRef(skia::CreatePlatformCanvas(pixel_size.width(),
                                                            pixel_size.height(),
                                                            is_opaque));
  canvas_ = owned_canvas_.get();
  SkScalar scale_scalar = SkFloatToScalar(image_scale);
  canvas_->scale(scale_scalar, scale_scalar);
}

// static
void Canvas::SizeStringInt(const base::string16& text,
                           const FontList& font_list,
                           int* width,
                           int* height,
                           int line_height,
                           int flags) {
  float fractional_width = *width;
  float factional_height = *height;
  SizeStringFloat(text, font_list, &fractional_width,
                  &factional_height, line_height, flags);
  *width = std::ceil(fractional_width);
  *height = std::ceil(factional_height);
}

// static
int Canvas::GetStringWidth(const base::string16& text,
                           const FontList& font_list) {
  int width = 0, height = 0;
  SizeStringInt(text, font_list, &width, &height, 0, NO_ELLIPSIS);
  return width;
}

// static
float Canvas::GetStringWidthF(const base::string16& text,
                              const FontList& font_list) {
  float width = 0, height = 0;
  SizeStringFloat(text, font_list, &width, &height, 0, NO_ELLIPSIS);
  return width;
}

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

ImageSkiaRep Canvas::ExtractImageRep() const {
  // 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.
  const SkISize size = canvas_->getDeviceSize();
  SkBitmap result;
  result.allocN32Pixels(size.width(), size.height());

  canvas_->readPixels(&result, 0, 0);
  return ImageSkiaRep(result, image_scale_);
}

void Canvas::DrawDashedRect(const 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->allocN32Pixels(col_pixels, row_pixels);
    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.
  skia::RefPtr<SkShader> shader = skia::AdoptRef(
      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.get());

  DrawRect(Rect(rect.x(), rect.y(), rect.width(), 1), paint);
  DrawRect(Rect(rect.x(), rect.y() + rect.height() - 1, rect.width(), 1),
           paint);
  DrawRect(Rect(rect.x(), rect.y(), 1, rect.height()), paint);
  DrawRect(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 Rect& layer_bounds) {
  SkRect bounds(RectToSkRect(layer_bounds));
  canvas_->saveLayerAlpha(&bounds, alpha);
}

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

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

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

bool Canvas::IsClipEmpty() const {
  return canvas_->isClipEmpty();
}

bool Canvas::GetClipBounds(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 Vector2d& offset) {
  canvas_->translate(SkIntToScalar(offset.x()), SkIntToScalar(offset.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 Rect& rect, SkColor color) {
  FillRect(rect, color, SkXfermode::kSrcOver_Mode);
}

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

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

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

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

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

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

void Canvas::DrawSolidFocusRect(const Rect& rect, SkColor color) {
  SkPaint paint;
  paint.setColor(color);
  paint.setStrokeWidth(SkIntToScalar(1));
  // Note: We cannot use DrawRect since it would create a path and fill it which
  // would cause problems near the edge of the canvas.
  int x1 = std::min(rect.x(), rect.right());
  int x2 = std::max(rect.x(), rect.right());
  int y1 = std::min(rect.y(), rect.bottom());
  int y2 = std::max(rect.y(), rect.bottom());
  DrawLine(Point(x1, y1), Point(x2, y1), paint);
  DrawLine(Point(x1, y2), Point(x2, y2), paint);
  DrawLine(Point(x1, y1), Point(x1, y2), paint);
  DrawLine(Point(x2, y1), Point(x2, y2 + 1), paint);
}

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

void Canvas::DrawImageInt(const ImageSkia& image, int x, int y, uint8 a) {
  SkPaint paint;
  paint.setAlpha(a);
  DrawImageInt(image, x, y, paint);
}

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

  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 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 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 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() == 1.0f) {
    // 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));

  skia::RefPtr<SkShader> shader = 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.get());

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

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

  SkMatrix matrix;
  matrix.setTranslate(SkIntToScalar(x), SkIntToScalar(y));
  skia::RefPtr<SkShader> shader = CreateImageRepShader(
      image_rep,
      SkShader::kRepeat_TileMode,
      matrix);

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

void Canvas::DrawStringRect(const base::string16& text,
                            const FontList& font_list,
                            SkColor color,
                            const Rect& display_rect) {
  DrawStringRectWithFlags(text, font_list, color, display_rect,
                          DefaultCanvasTextAlignment());
}

void Canvas::DrawStringRectWithFlags(const base::string16& text,
                                     const FontList& font_list,
                                     SkColor color,
                                     const Rect& display_rect,
                                     int flags) {
  DrawStringRectWithShadows(text, font_list, color, display_rect, 0, flags,
                            ShadowValues());
}

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

void Canvas::TileImageInt(const 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 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 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));

  skia::RefPtr<SkShader> shader = CreateImageRepShader(
      image_rep,
      SkShader::kRepeat_TileMode,
      shader_scale);

  SkPaint paint;
  paint.setShader(shader.get());
  paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);

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

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

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

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

Canvas::Canvas(SkCanvas* canvas, float image_scale)
    : image_scale_(image_scale),
      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 Rect& rect) {
  return IntersectsClipRectInt(rect.x(), rect.y(),
                               rect.width(), rect.height());
}

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

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

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

  return image_rep;
}

}  // namespace gfx
/* [<][>][^][v][top][bottom][index][help] */
root/ui/gfx/canvas.cc

DEFINITIONS
