ui/gfx/canvas.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/gfx/canvas.h"
   6
   7 #include <cmath>
   8 #include <limits>
   9
  10 #include "base/i18n/rtl.h"
  11 #include "base/logging.h"
  12 #include "third_party/skia/include/core/SkBitmap.h"
  13 #include "third_party/skia/include/effects/SkGradientShader.h"
  14 #include "ui/gfx/font_list.h"
  15 #include "ui/gfx/geometry/rect.h"
  16 #include "ui/gfx/geometry/rect_conversions.h"
  17 #include "ui/gfx/geometry/safe_integer_conversions.h"
  18 #include "ui/gfx/geometry/size_conversions.h"
  19 #include "ui/gfx/scoped_canvas.h"
  20 #include "ui/gfx/skia_util.h"
  21 #include "ui/gfx/transform.h"
  22
  23 namespace gfx {
  24
  25 Canvas::Canvas(const Size& size, float image_scale, bool is_opaque)
  26     : image_scale_(image_scale),
  27       canvas_(NULL) {
  28   Size pixel_size = ToCeiledSize(ScaleSize(size, image_scale));
  29   owned_canvas_ = skia::AdoptRef(skia::CreatePlatformCanvas(pixel_size.width(),
  30                                                             pixel_size.height(),
  31                                                             is_opaque));
  32   canvas_ = owned_canvas_.get();
  33 #if defined(OS_WIN) || defined(OS_MACOSX)
  34   // skia::PlatformCanvas instances are initialized to 0 by Cairo on Linux, but
  35   // uninitialized on Win and Mac.
  36   if (!is_opaque)
  37     owned_canvas_->clear(SkColorSetARGB(0, 0, 0, 0));
  38 #endif
  39
  40   SkScalar scale_scalar = SkFloatToScalar(image_scale);
  41   canvas_->scale(scale_scalar, scale_scalar);
  42 }
  43
  44 Canvas::Canvas(const ImageSkiaRep& image_rep, bool is_opaque)
  45     : image_scale_(image_rep.scale()),
  46       owned_canvas_(skia::AdoptRef(
  47           skia::CreatePlatformCanvas(image_rep.pixel_width(),
  48                                      image_rep.pixel_height(),
  49                                      is_opaque))),
  50       canvas_(owned_canvas_.get()) {
  51   SkScalar scale_scalar = SkFloatToScalar(image_scale_);
  52   canvas_->scale(scale_scalar, scale_scalar);
  53   DrawImageInt(ImageSkia(image_rep), 0, 0);
  54 }
  55
  56 Canvas::Canvas()
  57     : image_scale_(1.0),
  58       owned_canvas_(skia::AdoptRef(skia::CreatePlatformCanvas(0, 0, false))),
  59       canvas_(owned_canvas_.get()) {
  60 }
  61
  62 Canvas::Canvas(SkCanvas* canvas, float image_scale)
  63     : image_scale_(image_scale), owned_canvas_(), canvas_(canvas) {
  64   DCHECK(canvas);
  65 }
  66
  67 Canvas::~Canvas() {
  68 }
  69
  70 void Canvas::RecreateBackingCanvas(const Size& size,
  71                                    float image_scale,
  72                                    bool is_opaque) {
  73   image_scale_ = image_scale;
  74   Size pixel_size = ToFlooredSize(ScaleSize(size, image_scale));
  75   owned_canvas_ = skia::AdoptRef(skia::CreatePlatformCanvas(pixel_size.width(),
  76                                                             pixel_size.height(),
  77                                                             is_opaque));
  78   canvas_ = owned_canvas_.get();
  79   SkScalar scale_scalar = SkFloatToScalar(image_scale);
  80   canvas_->scale(scale_scalar, scale_scalar);
  81 }
  82
  83 // static
  84 void Canvas::SizeStringInt(const base::string16& text,
  85                            const FontList& font_list,
  86                            int* width,
  87                            int* height,
  88                            int line_height,
  89                            int flags) {
  90   float fractional_width = static_cast<float>(*width);
  91   float factional_height = static_cast<float>(*height);
  92   SizeStringFloat(text, font_list, &fractional_width,
  93                   &factional_height, line_height, flags);
  94   *width = ToCeiledInt(fractional_width);
  95   *height = ToCeiledInt(factional_height);
  96 }
  97
  98 // static
  99 int Canvas::GetStringWidth(const base::string16& text,
 100                            const FontList& font_list) {
 101   int width = 0, height = 0;
 102   SizeStringInt(text, font_list, &width, &height, 0, NO_ELLIPSIS);
 103   return width;
 104 }
 105
 106 // static
 107 float Canvas::GetStringWidthF(const base::string16& text,
 108                               const FontList& font_list) {
 109   float width = 0, height = 0;
 110   SizeStringFloat(text, font_list, &width, &height, 0, NO_ELLIPSIS);
 111   return width;
 112 }
 113
 114 // static
 115 int Canvas::DefaultCanvasTextAlignment() {
 116   return base::i18n::IsRTL() ? TEXT_ALIGN_RIGHT : TEXT_ALIGN_LEFT;
 117 }
 118
 119 ImageSkiaRep Canvas::ExtractImageRep() const {
 120   // Make a bitmap to return, and a canvas to draw into it. We don't just want
 121   // to call extractSubset or the copy constructor, since we want an actual copy
 122   // of the bitmap.
 123   const SkISize size = canvas_->getDeviceSize();
 124   SkBitmap result;
 125   result.allocN32Pixels(size.width(), size.height());
 126
 127   canvas_->readPixels(&result, 0, 0);
 128   return ImageSkiaRep(result, image_scale_);
 129 }
 130
 131 void Canvas::DrawDashedRect(const Rect& rect, SkColor color) {
 132   if (rect.IsEmpty())
 133     return;
 134   // Create a 2D bitmap containing alternating on/off pixels - we do this
 135   // so that you never get two pixels of the same color around the edges
 136   // of the focus rect (this may mean that opposing edges of the rect may
 137   // have a dot pattern out of phase to each other).
 138   static SkColor last_color;
 139   static SkBitmap* dots = NULL;
 140   if (!dots || last_color != color) {
 141     int col_pixels = 32;
 142     int row_pixels = 32;
 143
 144     delete dots;
 145     last_color = color;
 146     dots = new SkBitmap;
 147     dots->allocN32Pixels(col_pixels, row_pixels);
 148     dots->eraseARGB(0, 0, 0, 0);
 149
 150     uint32_t* dot = dots->getAddr32(0, 0);
 151     for (int i = 0; i < row_pixels; i++) {
 152       for (int u = 0; u < col_pixels; u++) {
 153         if ((u % 2 + i % 2) % 2 != 0) {
 154           dot[i * row_pixels + u] = color;
 155         }
 156       }
 157     }
 158   }
 159
 160   // Make a shader for the bitmap with an origin of the box we'll draw. This
 161   // shader is refcounted and will have an initial refcount of 1.
 162   skia::RefPtr<SkShader> shader = skia::AdoptRef(
 163       SkShader::CreateBitmapShader(
 164           *dots, SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode));
 165   // Assign the shader to the paint & release our reference. The paint will
 166   // now own the shader and the shader will be destroyed when the paint goes
 167   // out of scope.
 168   SkPaint paint;
 169   paint.setShader(shader.get());
 170
 171   DrawRect(Rect(rect.x(), rect.y(), rect.width(), 1), paint);
 172   DrawRect(Rect(rect.x(), rect.y() + rect.height() - 1, rect.width(), 1),
 173            paint);
 174   DrawRect(Rect(rect.x(), rect.y(), 1, rect.height()), paint);
 175   DrawRect(Rect(rect.x() + rect.width() - 1, rect.y(), 1, rect.height()),
 176            paint);
 177 }
 178
 179 void Canvas::Save() {
 180   canvas_->save();
 181 }
 182
 183 void Canvas::SaveLayerAlpha(uint8 alpha) {
 184   canvas_->saveLayerAlpha(NULL, alpha);
 185 }
 186
 187 void Canvas::SaveLayerAlpha(uint8 alpha, const Rect& layer_bounds) {
 188   SkRect bounds(RectToSkRect(layer_bounds));
 189   canvas_->saveLayerAlpha(&bounds, alpha);
 190 }
 191
 192 void Canvas::Restore() {
 193   canvas_->restore();
 194 }
 195
 196 void Canvas::ClipRect(const Rect& rect) {
 197   canvas_->clipRect(RectToSkRect(rect));
 198 }
 199
 200 void Canvas::ClipPath(const SkPath& path, bool do_anti_alias) {
 201   canvas_->clipPath(path, SkRegion::kIntersect_Op, do_anti_alias);
 202 }
 203
 204 bool Canvas::IsClipEmpty() const {
 205   return canvas_->isClipEmpty();
 206 }
 207
 208 bool Canvas::GetClipBounds(Rect* bounds) {
 209   SkRect out;
 210   if (canvas_->getClipBounds(&out)) {
 211     *bounds = ToEnclosingRect(SkRectToRectF(out));
 212     return true;
 213   }
 214   *bounds = gfx::Rect();
 215   return false;
 216 }
 217
 218 void Canvas::Translate(const Vector2d& offset) {
 219   canvas_->translate(SkIntToScalar(offset.x()), SkIntToScalar(offset.y()));
 220 }
 221
 222 void Canvas::Scale(int x_scale, int y_scale) {
 223   canvas_->scale(SkIntToScalar(x_scale), SkIntToScalar(y_scale));
 224 }
 225
 226 void Canvas::DrawColor(SkColor color) {
 227   DrawColor(color, SkXfermode::kSrcOver_Mode);
 228 }
 229
 230 void Canvas::DrawColor(SkColor color, SkXfermode::Mode mode) {
 231   canvas_->drawColor(color, mode);
 232 }
 233
 234 void Canvas::FillRect(const Rect& rect, SkColor color) {
 235   FillRect(rect, color, SkXfermode::kSrcOver_Mode);
 236 }
 237
 238 void Canvas::FillRect(const Rect& rect,
 239                       SkColor color,
 240                       SkXfermode::Mode mode) {
 241   SkPaint paint;
 242   paint.setColor(color);
 243   paint.setStyle(SkPaint::kFill_Style);
 244   paint.setXfermodeMode(mode);
 245   DrawRect(rect, paint);
 246 }
 247
 248 void Canvas::DrawRect(const Rect& rect, SkColor color) {
 249   DrawRect(rect, color, SkXfermode::kSrcOver_Mode);
 250 }
 251
 252 void Canvas::DrawRect(const Rect& rect,
 253                       SkColor color,
 254                       SkXfermode::Mode mode) {
 255   SkPaint paint;
 256   paint.setColor(color);
 257   paint.setStyle(SkPaint::kStroke_Style);
 258   // Set a stroke width of 0, which will put us down the stroke rect path.  If
 259   // we set a stroke width of 1, for example, this will internally create a
 260   // path and fill it, which causes problems near the edge of the canvas.
 261   paint.setStrokeWidth(SkIntToScalar(0));
 262   paint.setXfermodeMode(mode);
 263
 264   DrawRect(rect, paint);
 265 }
 266
 267 void Canvas::DrawRect(const Rect& rect, const SkPaint& paint) {
 268   canvas_->drawIRect(RectToSkIRect(rect), paint);
 269 }
 270
 271 void Canvas::DrawPoint(const Point& p1, const SkPaint& paint) {
 272   canvas_->drawPoint(SkIntToScalar(p1.x()), SkIntToScalar(p1.y()), paint);
 273 }
 274
 275 void Canvas::DrawLine(const Point& p1, const Point& p2, SkColor color) {
 276   SkPaint paint;
 277   paint.setColor(color);
 278   paint.setStrokeWidth(SkIntToScalar(1));
 279   DrawLine(p1, p2, paint);
 280 }
 281
 282 void Canvas::DrawLine(const Point& p1, const Point& p2, const SkPaint& paint) {
 283   canvas_->drawLine(SkIntToScalar(p1.x()), SkIntToScalar(p1.y()),
 284                     SkIntToScalar(p2.x()), SkIntToScalar(p2.y()), paint);
 285 }
 286
 287 void Canvas::DrawCircle(const Point& center_point,
 288                         int radius,
 289                         const SkPaint& paint) {
 290   canvas_->drawCircle(SkIntToScalar(center_point.x()),
 291       SkIntToScalar(center_point.y()), SkIntToScalar(radius), paint);
 292 }
 293
 294 void Canvas::DrawRoundRect(const Rect& rect,
 295                            int radius,
 296                            const SkPaint& paint) {
 297   canvas_->drawRoundRect(RectToSkRect(rect), SkIntToScalar(radius),
 298                          SkIntToScalar(radius), paint);
 299 }
 300
 301 void Canvas::DrawPath(const SkPath& path, const SkPaint& paint) {
 302   canvas_->drawPath(path, paint);
 303 }
 304
 305 void Canvas::DrawFocusRect(const Rect& rect) {
 306   DrawDashedRect(rect, SK_ColorGRAY);
 307 }
 308
 309 void Canvas::DrawSolidFocusRect(const Rect& rect, SkColor color) {
 310   SkPaint paint;
 311   paint.setColor(color);
 312   paint.setStrokeWidth(SkIntToScalar(1));
 313   // Note: We cannot use DrawRect since it would create a path and fill it which
 314   // would cause problems near the edge of the canvas.
 315   int x1 = std::min(rect.x(), rect.right());
 316   int x2 = std::max(rect.x(), rect.right());
 317   int y1 = std::min(rect.y(), rect.bottom());
 318   int y2 = std::max(rect.y(), rect.bottom());
 319   DrawLine(Point(x1, y1), Point(x2, y1), paint);
 320   DrawLine(Point(x1, y2), Point(x2, y2), paint);
 321   DrawLine(Point(x1, y1), Point(x1, y2), paint);
 322   DrawLine(Point(x2, y1), Point(x2, y2 + 1), paint);
 323 }
 324
 325 void Canvas::DrawImageInt(const ImageSkia& image, int x, int y) {
 326   SkPaint paint;
 327   DrawImageInt(image, x, y, paint);
 328 }
 329
 330 void Canvas::DrawImageInt(const ImageSkia& image, int x, int y, uint8 a) {
 331   SkPaint paint;
 332   paint.setAlpha(a);
 333   DrawImageInt(image, x, y, paint);
 334 }
 335
 336 void Canvas::DrawImageInt(const ImageSkia& image,
 337                           int x,
 338                           int y,
 339                           const SkPaint& paint) {
 340   const ImageSkiaRep& image_rep = image.GetRepresentation(image_scale_);
 341   if (image_rep.is_null())
 342     return;
 343   const SkBitmap& bitmap = image_rep.sk_bitmap();
 344   float bitmap_scale = image_rep.scale();
 345
 346   ScopedCanvas scoper(this);
 347   canvas_->scale(SkFloatToScalar(1.0f / bitmap_scale),
 348                  SkFloatToScalar(1.0f / bitmap_scale));
 349   canvas_->drawBitmap(bitmap,
 350                       SkFloatToScalar(x * bitmap_scale),
 351                       SkFloatToScalar(y * bitmap_scale),
 352                       &paint);
 353 }
 354
 355 void Canvas::DrawImageInt(const ImageSkia& image,
 356                           int src_x,
 357                           int src_y,
 358                           int src_w,
 359                           int src_h,
 360                           int dest_x,
 361                           int dest_y,
 362                           int dest_w,
 363                           int dest_h,
 364                           bool filter) {
 365   SkPaint p;
 366   DrawImageInt(image, src_x, src_y, src_w, src_h, dest_x, dest_y,
 367                dest_w, dest_h, filter, p);
 368 }
 369
 370 void Canvas::DrawImageInt(const ImageSkia& image,
 371                           int src_x,
 372                           int src_y,
 373                           int src_w,
 374                           int src_h,
 375                           int dest_x,
 376                           int dest_y,
 377                           int dest_w,
 378                           int dest_h,
 379                           bool filter,
 380                           const SkPaint& paint) {
 381   DrawImageIntHelper(image, src_x, src_y, src_w, src_h, dest_x, dest_y, dest_w,
 382                      dest_h, filter, paint, image_scale_, false);
 383 }
 384
 385 void Canvas::DrawImageIntInPixel(const ImageSkia& image,
 386                                  int src_x,
 387                                  int src_y,
 388                                  int src_w,
 389                                  int src_h,
 390                                  int dest_x,
 391                                  int dest_y,
 392                                  int dest_w,
 393                                  int dest_h,
 394                                  bool filter,
 395                                  const SkPaint& paint) {
 396   // All values passed into this function are in pixels, i.e. no scaling needs
 397   // be done.
 398   // Logic as below:-
 399   // 1. Get the matrix transform from the canvas.
 400   // 2. Set the scale in the matrix to 1.0 while honoring the direction of the
 401   //    the scale (x/y). Example RTL layouts.
 402   // 3. Round off the X and Y translation components in the matrix. This is to
 403   //    reduce floating point errors during rect transformation. This is needed
 404   //    for fractional scale factors like 1.25/1.5, etc.
 405   // 4. Save the current state of the canvas and restore the state when going
 406   //    out of scope with ScopedCanvas.
 407   // 5. Set the modified matrix in the canvas. This ensures that no scaling
 408   //    will be done for draw operations on the canvas.
 409   // 6. Draw the image.
 410   SkMatrix matrix = canvas_->getTotalMatrix();
 411
 412   // Ensure that the direction of the x and y scales is preserved. This is
 413   // important for RTL layouts.
 414   matrix.setScaleX(matrix.getScaleX() > 0 ? 1.0f : -1.0f);
 415   matrix.setScaleY(matrix.getScaleY() > 0 ? 1.0f : -1.0f);
 416
 417   // Floor so that we get consistent rounding.
 418   matrix.setTranslateX(SkScalarFloorToScalar(matrix.getTranslateX()));
 419   matrix.setTranslateY(SkScalarFloorToScalar(matrix.getTranslateY()));
 420
 421   ScopedCanvas scoper(this);
 422
 423   canvas_->setMatrix(matrix);
 424
 425   DrawImageIntHelper(image,
 426                      src_x,
 427                      src_y,
 428                      src_w,
 429                      src_h,
 430                      dest_x,
 431                      dest_y,
 432                      dest_w,
 433                      dest_h,
 434                      filter,
 435                      paint,
 436                      image_scale_,
 437                      true);
 438 }
 439
 440 void Canvas::DrawImageInPath(const ImageSkia& image,
 441                              int x,
 442                              int y,
 443                              const SkPath& path,
 444                              const SkPaint& paint) {
 445   const ImageSkiaRep& image_rep = image.GetRepresentation(image_scale_);
 446   if (image_rep.is_null())
 447     return;
 448
 449   SkMatrix matrix;
 450   matrix.setTranslate(SkIntToScalar(x), SkIntToScalar(y));
 451   skia::RefPtr<SkShader> shader = CreateImageRepShader(
 452       image_rep,
 453       SkShader::kRepeat_TileMode,
 454       matrix);
 455
 456   SkPaint p(paint);
 457   p.setShader(shader.get());
 458   canvas_->drawPath(path, p);
 459 }
 460
 461 void Canvas::DrawStringRect(const base::string16& text,
 462                             const FontList& font_list,
 463                             SkColor color,
 464                             const Rect& display_rect) {
 465   DrawStringRectWithFlags(text, font_list, color, display_rect,
 466                           DefaultCanvasTextAlignment());
 467 }
 468
 469 void Canvas::DrawStringRectWithFlags(const base::string16& text,
 470                                      const FontList& font_list,
 471                                      SkColor color,
 472                                      const Rect& display_rect,
 473                                      int flags) {
 474   DrawStringRectWithShadows(text, font_list, color, display_rect, 0, flags,
 475                             ShadowValues());
 476 }
 477
 478 void Canvas::TileImageInt(const ImageSkia& image,
 479                           int x,
 480                           int y,
 481                           int w,
 482                           int h) {
 483   TileImageInt(image, 0, 0, x, y, w, h);
 484 }
 485
 486 void Canvas::TileImageInt(const ImageSkia& image,
 487                           int src_x,
 488                           int src_y,
 489                           int dest_x,
 490                           int dest_y,
 491                           int w,
 492                           int h) {
 493   TileImageInt(image, src_x, src_y, 1.0f, 1.0f, dest_x, dest_y, w, h);
 494 }
 495
 496 void Canvas::TileImageInt(const ImageSkia& image,
 497                           int src_x,
 498                           int src_y,
 499                           float tile_scale_x,
 500                           float tile_scale_y,
 501                           int dest_x,
 502                           int dest_y,
 503                           int w,
 504                           int h) {
 505   if (!IntersectsClipRectInt(dest_x, dest_y, w, h))
 506     return;
 507
 508   const ImageSkiaRep& image_rep = image.GetRepresentation(image_scale_);
 509   if (image_rep.is_null())
 510     return;
 511
 512   SkMatrix shader_scale;
 513   shader_scale.setScale(SkFloatToScalar(tile_scale_x),
 514                         SkFloatToScalar(tile_scale_y));
 515   shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
 516   shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));
 517
 518   skia::RefPtr<SkShader> shader = CreateImageRepShader(
 519       image_rep,
 520       SkShader::kRepeat_TileMode,
 521       shader_scale);
 522
 523   SkPaint paint;
 524   paint.setShader(shader.get());
 525   paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
 526
 527   SkRect dest_rect = { SkIntToScalar(dest_x),
 528                        SkIntToScalar(dest_y),
 529                        SkIntToScalar(dest_x + w),
 530                        SkIntToScalar(dest_y + h) };
 531   canvas_->drawRect(dest_rect, paint);
 532 }
 533
 534 NativeDrawingContext Canvas::BeginPlatformPaint() {
 535   return skia::BeginPlatformPaint(canvas_);
 536 }
 537
 538 void Canvas::EndPlatformPaint() {
 539   skia::EndPlatformPaint(canvas_);
 540 }
 541
 542 void Canvas::Transform(const gfx::Transform& transform) {
 543   canvas_->concat(transform.matrix());
 544 }
 545
 546 bool Canvas::IntersectsClipRectInt(int x, int y, int w, int h) {
 547   SkRect clip;
 548   return canvas_->getClipBounds(&clip) &&
 549       clip.intersect(SkIntToScalar(x), SkIntToScalar(y), SkIntToScalar(x + w),
 550                      SkIntToScalar(y + h));
 551 }
 552
 553 bool Canvas::IntersectsClipRect(const Rect& rect) {
 554   return IntersectsClipRectInt(rect.x(), rect.y(),
 555                                rect.width(), rect.height());
 556 }
 557
 558 void Canvas::DrawImageIntHelper(const ImageSkia& image,
 559                                 int src_x,
 560                                 int src_y,
 561                                 int src_w,
 562                                 int src_h,
 563                                 int dest_x,
 564                                 int dest_y,
 565                                 int dest_w,
 566                                 int dest_h,
 567                                 bool filter,
 568                                 const SkPaint& paint,
 569                                 float image_scale,
 570                                 bool pixel) {
 571   DLOG_ASSERT(src_x + src_w < std::numeric_limits<int16_t>::max() &&
 572               src_y + src_h < std::numeric_limits<int16_t>::max());
 573   if (src_w <= 0 || src_h <= 0) {
 574     NOTREACHED() << "Attempting to draw bitmap from an empty rect!";
 575     return;
 576   }
 577
 578   if (!IntersectsClipRectInt(dest_x, dest_y, dest_w, dest_h))
 579     return;
 580
 581   float user_scale_x = static_cast<float>(dest_w) / src_w;
 582   float user_scale_y = static_cast<float>(dest_h) / src_h;
 583
 584   const ImageSkiaRep& image_rep = image.GetRepresentation(image_scale);
 585   if (image_rep.is_null())
 586     return;
 587
 588   SkRect dest_rect = { SkIntToScalar(dest_x),
 589                        SkIntToScalar(dest_y),
 590                        SkIntToScalar(dest_x + dest_w),
 591                        SkIntToScalar(dest_y + dest_h) };
 592
 593   if (src_w == dest_w && src_h == dest_h &&
 594       user_scale_x == 1.0f && user_scale_y == 1.0f &&
 595       image_rep.scale() == 1.0f && !pixel) {
 596     // Workaround for apparent bug in Skia that causes image to occasionally
 597     // shift.
 598     SkIRect src_rect = { src_x, src_y, src_x + src_w, src_y + src_h };
 599     const SkBitmap& bitmap = image_rep.sk_bitmap();
 600     canvas_->drawBitmapRect(bitmap, src_rect, dest_rect, &paint);
 601     return;
 602   }
 603
 604   // Make a bitmap shader that contains the bitmap we want to draw. This is
 605   // basically what SkCanvas.drawBitmap does internally, but it gives us
 606   // more control over quality and will use the mipmap in the source image if
 607   // it has one, whereas drawBitmap won't.
 608   SkMatrix shader_scale;
 609   shader_scale.setScale(SkFloatToScalar(user_scale_x),
 610                         SkFloatToScalar(user_scale_y));
 611   shader_scale.preTranslate(SkIntToScalar(-src_x), SkIntToScalar(-src_y));
 612   shader_scale.postTranslate(SkIntToScalar(dest_x), SkIntToScalar(dest_y));
 613
 614   skia::RefPtr<SkShader> shader = CreateImageRepShaderForScale(
 615       image_rep,
 616       SkShader::kRepeat_TileMode,
 617       shader_scale,
 618       pixel ? 1.0f : image_rep.scale());
 619
 620   // Set up our paint to use the shader & release our reference (now just owned
 621   // by the paint).
 622   SkPaint p(paint);
 623   p.setFilterQuality(filter ? kLow_SkFilterQuality : kNone_SkFilterQuality);
 624   p.setShader(shader.get());
 625
 626   // The rect will be filled by the bitmap.
 627   canvas_->drawRect(dest_rect, p);
 628 }
 629
 630 }  // namespace gfx