src/skia/ext/pixel_ref_utils.cc

   1 // Copyright 2014 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 "skia/ext/pixel_ref_utils.h"
   6
   7 #include <algorithm>
   8
   9 #include "third_party/skia/include/core/SkBitmapDevice.h"
  10 #include "third_party/skia/include/core/SkCanvas.h"
  11 #include "third_party/skia/include/core/SkData.h"
  12 #include "third_party/skia/include/core/SkDraw.h"
  13 #include "third_party/skia/include/core/SkPixelRef.h"
  14 #include "third_party/skia/include/core/SkRRect.h"
  15 #include "third_party/skia/include/core/SkRect.h"
  16 #include "third_party/skia/include/core/SkShader.h"
  17 #include "third_party/skia/include/utils/SkNoSaveLayerCanvas.h"
  18 #include "third_party/skia/src/core/SkRasterClip.h"
  19
  20 namespace skia {
  21
  22 namespace {
  23
  24 // URI label for a discardable SkPixelRef.
  25 const char kLabelDiscardable[] = "discardable";
  26
  27 class DiscardablePixelRefSet {
  28  public:
  29   DiscardablePixelRefSet(
  30       std::vector<PixelRefUtils::PositionPixelRef>* pixel_refs)
  31       : pixel_refs_(pixel_refs) {}
  32
  33   void Add(SkPixelRef* pixel_ref, const SkRect& rect) {
  34     // Only save discardable pixel refs.
  35     if (pixel_ref->getURI() &&
  36         !strcmp(pixel_ref->getURI(), kLabelDiscardable)) {
  37       PixelRefUtils::PositionPixelRef position_pixel_ref;
  38       position_pixel_ref.pixel_ref = pixel_ref;
  39       position_pixel_ref.pixel_ref_rect = rect;
  40       pixel_refs_->push_back(position_pixel_ref);
  41     }
  42   }
  43
  44  private:
  45   std::vector<PixelRefUtils::PositionPixelRef>* pixel_refs_;
  46 };
  47
  48 class GatherPixelRefDevice : public SkBitmapDevice {
  49  public:
  50   GatherPixelRefDevice(const SkBitmap& bm,
  51                        DiscardablePixelRefSet* pixel_ref_set)
  52       : SkBitmapDevice(bm), pixel_ref_set_(pixel_ref_set) {}
  53
  54   void clear(SkColor color) override {}
  55   void drawPaint(const SkDraw& draw, const SkPaint& paint) override {
  56     SkBitmap bitmap;
  57     if (GetBitmapFromPaint(paint, &bitmap)) {
  58       SkRect clip_rect = SkRect::Make(draw.fRC->getBounds());
  59       AddBitmap(bitmap, clip_rect);
  60     }
  61   }
  62
  63   void drawPoints(const SkDraw& draw,
  64                   SkCanvas::PointMode mode,
  65                   size_t count,
  66                   const SkPoint points[],
  67                   const SkPaint& paint) override {
  68     SkBitmap bitmap;
  69     if (!GetBitmapFromPaint(paint, &bitmap))
  70       return;
  71
  72     if (count == 0)
  73       return;
  74
  75     SkPoint min_point = points[0];
  76     SkPoint max_point = points[0];
  77     for (size_t i = 1; i < count; ++i) {
  78       const SkPoint& point = points[i];
  79       min_point.set(std::min(min_point.x(), point.x()),
  80                     std::min(min_point.y(), point.y()));
  81       max_point.set(std::max(max_point.x(), point.x()),
  82                     std::max(max_point.y(), point.y()));
  83     }
  84
  85     SkRect bounds = SkRect::MakeLTRB(
  86         min_point.x(), min_point.y(), max_point.x(), max_point.y());
  87
  88     GatherPixelRefDevice::drawRect(draw, bounds, paint);
  89   }
  90   void drawRect(const SkDraw& draw,
  91                 const SkRect& rect,
  92                 const SkPaint& paint) override {
  93     SkBitmap bitmap;
  94     if (GetBitmapFromPaint(paint, &bitmap)) {
  95       SkRect mapped_rect;
  96       draw.fMatrix->mapRect(&mapped_rect, rect);
  97       mapped_rect.intersect(SkRect::Make(draw.fRC->getBounds()));
  98       AddBitmap(bitmap, mapped_rect);
  99     }
 100   }
 101   void drawOval(const SkDraw& draw,
 102                 const SkRect& rect,
 103                 const SkPaint& paint) override {
 104     GatherPixelRefDevice::drawRect(draw, rect, paint);
 105   }
 106   void drawRRect(const SkDraw& draw,
 107                  const SkRRect& rect,
 108                  const SkPaint& paint) override {
 109     GatherPixelRefDevice::drawRect(draw, rect.rect(), paint);
 110   }
 111   void drawPath(const SkDraw& draw,
 112                 const SkPath& path,
 113                 const SkPaint& paint,
 114                 const SkMatrix* pre_path_matrix,
 115                 bool path_is_mutable) override {
 116     SkBitmap bitmap;
 117     if (!GetBitmapFromPaint(paint, &bitmap))
 118       return;
 119
 120     SkRect path_bounds = path.getBounds();
 121     SkRect final_rect;
 122     if (pre_path_matrix != NULL)
 123       pre_path_matrix->mapRect(&final_rect, path_bounds);
 124     else
 125       final_rect = path_bounds;
 126
 127     GatherPixelRefDevice::drawRect(draw, final_rect, paint);
 128   }
 129   void drawBitmap(const SkDraw& draw,
 130                   const SkBitmap& bitmap,
 131                   const SkMatrix& matrix,
 132                   const SkPaint& paint) override {
 133     SkMatrix total_matrix;
 134     total_matrix.setConcat(*draw.fMatrix, matrix);
 135
 136     SkRect bitmap_rect = SkRect::MakeWH(bitmap.width(), bitmap.height());
 137     SkRect mapped_rect;
 138     total_matrix.mapRect(&mapped_rect, bitmap_rect);
 139     AddBitmap(bitmap, mapped_rect);
 140
 141     SkBitmap paint_bitmap;
 142     if (GetBitmapFromPaint(paint, &paint_bitmap))
 143       AddBitmap(paint_bitmap, mapped_rect);
 144   }
 145   void drawBitmapRect(const SkDraw& draw,
 146                       const SkBitmap& bitmap,
 147                       const SkRect* src_or_null,
 148                       const SkRect& dst,
 149                       const SkPaint& paint,
 150                       SkCanvas::DrawBitmapRectFlags flags) override {
 151     SkRect bitmap_rect = SkRect::MakeWH(bitmap.width(), bitmap.height());
 152     SkMatrix matrix;
 153     matrix.setRectToRect(bitmap_rect, dst, SkMatrix::kFill_ScaleToFit);
 154     GatherPixelRefDevice::drawBitmap(draw, bitmap, matrix, paint);
 155   }
 156   void drawSprite(const SkDraw& draw,
 157                   const SkBitmap& bitmap,
 158                   int x,
 159                   int y,
 160                   const SkPaint& paint) override {
 161     // Sprites aren't affected by current matrix, so we can't reuse drawRect.
 162     SkMatrix matrix;
 163     matrix.setTranslate(x, y);
 164
 165     SkRect bitmap_rect = SkRect::MakeWH(bitmap.width(), bitmap.height());
 166     SkRect mapped_rect;
 167     matrix.mapRect(&mapped_rect, bitmap_rect);
 168
 169     AddBitmap(bitmap, mapped_rect);
 170     SkBitmap paint_bitmap;
 171     if (GetBitmapFromPaint(paint, &paint_bitmap))
 172       AddBitmap(paint_bitmap, mapped_rect);
 173   }
 174   void drawText(const SkDraw& draw,
 175                 const void* text,
 176                 size_t len,
 177                 SkScalar x,
 178                 SkScalar y,
 179                 const SkPaint& paint) override {
 180     SkBitmap bitmap;
 181     if (!GetBitmapFromPaint(paint, &bitmap))
 182       return;
 183
 184     // Math is borrowed from SkBBoxRecord
 185     SkRect bounds;
 186     paint.measureText(text, len, &bounds);
 187     SkPaint::FontMetrics metrics;
 188     paint.getFontMetrics(&metrics);
 189
 190     if (paint.isVerticalText()) {
 191       SkScalar h = bounds.fBottom - bounds.fTop;
 192       if (paint.getTextAlign() == SkPaint::kCenter_Align) {
 193         bounds.fTop -= h / 2;
 194         bounds.fBottom -= h / 2;
 195       }
 196       bounds.fBottom += metrics.fBottom;
 197       bounds.fTop += metrics.fTop;
 198     } else {
 199       SkScalar w = bounds.fRight - bounds.fLeft;
 200       if (paint.getTextAlign() == SkPaint::kCenter_Align) {
 201         bounds.fLeft -= w / 2;
 202         bounds.fRight -= w / 2;
 203       } else if (paint.getTextAlign() == SkPaint::kRight_Align) {
 204         bounds.fLeft -= w;
 205         bounds.fRight -= w;
 206       }
 207       bounds.fTop = metrics.fTop;
 208       bounds.fBottom = metrics.fBottom;
 209     }
 210
 211     SkScalar pad = (metrics.fBottom - metrics.fTop) / 2;
 212     bounds.fLeft -= pad;
 213     bounds.fRight += pad;
 214     bounds.fLeft += x;
 215     bounds.fRight += x;
 216     bounds.fTop += y;
 217     bounds.fBottom += y;
 218
 219     GatherPixelRefDevice::drawRect(draw, bounds, paint);
 220   }
 221   void drawPosText(const SkDraw& draw,
 222                    const void* text,
 223                    size_t len,
 224                    const SkScalar pos[],
 225                    int scalars_per_pos,
 226                    const SkPoint& offset,
 227                    const SkPaint& paint) override {
 228     SkBitmap bitmap;
 229     if (!GetBitmapFromPaint(paint, &bitmap))
 230       return;
 231
 232     if (len == 0)
 233       return;
 234
 235     // Similar to SkDraw asserts.
 236     SkASSERT(scalars_per_pos == 1 || scalars_per_pos == 2);
 237
 238     SkPoint min_point = SkPoint::Make(offset.x() + pos[0],
 239                                       offset.y() + (2 == scalars_per_pos ? pos[1] : 0));
 240     SkPoint max_point = min_point;
 241
 242     for (size_t i = 0; i < len; ++i) {
 243       SkScalar x = offset.x() + pos[i * scalars_per_pos];
 244       SkScalar y = offset.y() + (2 == scalars_per_pos ? pos[i * scalars_per_pos + 1] : 0);
 245
 246       min_point.set(std::min(x, min_point.x()), std::min(y, min_point.y()));
 247       max_point.set(std::max(x, max_point.x()), std::max(y, max_point.y()));
 248     }
 249
 250     SkRect bounds = SkRect::MakeLTRB(
 251         min_point.x(), min_point.y(), max_point.x(), max_point.y());
 252
 253     // Math is borrowed from SkBBoxRecord
 254     SkPaint::FontMetrics metrics;
 255     paint.getFontMetrics(&metrics);
 256
 257     bounds.fTop += metrics.fTop;
 258     bounds.fBottom += metrics.fBottom;
 259
 260     SkScalar pad = (metrics.fTop - metrics.fBottom) / 2;
 261     bounds.fLeft += pad;
 262     bounds.fRight -= pad;
 263
 264     GatherPixelRefDevice::drawRect(draw, bounds, paint);
 265   }
 266   void drawTextOnPath(const SkDraw& draw,
 267                       const void* text,
 268                       size_t len,
 269                       const SkPath& path,
 270                       const SkMatrix* matrix,
 271                       const SkPaint& paint) override {
 272     SkBitmap bitmap;
 273     if (!GetBitmapFromPaint(paint, &bitmap))
 274       return;
 275
 276     // Math is borrowed from SkBBoxRecord
 277     SkRect bounds = path.getBounds();
 278     SkPaint::FontMetrics metrics;
 279     paint.getFontMetrics(&metrics);
 280
 281     SkScalar pad = metrics.fTop;
 282     bounds.fLeft += pad;
 283     bounds.fRight -= pad;
 284     bounds.fTop += pad;
 285     bounds.fBottom -= pad;
 286
 287     GatherPixelRefDevice::drawRect(draw, bounds, paint);
 288   }
 289   void drawVertices(const SkDraw& draw,
 290                     SkCanvas::VertexMode,
 291                     int vertex_count,
 292                     const SkPoint verts[],
 293                     const SkPoint texs[],
 294                     const SkColor colors[],
 295                     SkXfermode* xmode,
 296                     const uint16_t indices[],
 297                     int index_count,
 298                     const SkPaint& paint) override {
 299     GatherPixelRefDevice::drawPoints(
 300         draw, SkCanvas::kPolygon_PointMode, vertex_count, verts, paint);
 301   }
 302   void drawDevice(const SkDraw&,
 303                   SkBaseDevice*,
 304                   int x,
 305                   int y,
 306                   const SkPaint&) override {}
 307
 308  protected:
 309   bool onReadPixels(const SkImageInfo& info,
 310                     void* pixels,
 311                     size_t rowBytes,
 312                     int x,
 313                     int y) override {
 314     return false;
 315   }
 316
 317   bool onWritePixels(const SkImageInfo& info,
 318                      const void* pixels,
 319                      size_t rowBytes,
 320                      int x,
 321                      int y) override {
 322     return false;
 323   }
 324
 325  private:
 326   DiscardablePixelRefSet* pixel_ref_set_;
 327
 328   void AddBitmap(const SkBitmap& bm, const SkRect& rect) {
 329     SkRect canvas_rect = SkRect::MakeWH(width(), height());
 330     SkRect paint_rect = SkRect::MakeEmpty();
 331     paint_rect.intersect(rect, canvas_rect);
 332     pixel_ref_set_->Add(bm.pixelRef(), paint_rect);
 333   }
 334
 335   bool GetBitmapFromPaint(const SkPaint& paint, SkBitmap* bm) {
 336     SkShader* shader = paint.getShader();
 337     if (shader) {
 338       // Check whether the shader is a gradient in order to prevent generation
 339       // of bitmaps from gradient shaders, which implement asABitmap.
 340       if (SkShader::kNone_GradientType == shader->asAGradient(NULL))
 341         return shader->asABitmap(bm, NULL, NULL);
 342     }
 343     return false;
 344   }
 345 };
 346
 347 }  // namespace
 348
 349 void PixelRefUtils::GatherDiscardablePixelRefs(
 350     SkPicture* picture,
 351     std::vector<PositionPixelRef>* pixel_refs) {
 352   pixel_refs->clear();
 353   DiscardablePixelRefSet pixel_ref_set(pixel_refs);
 354
 355   SkBitmap empty_bitmap;
 356   empty_bitmap.setInfo(SkImageInfo::MakeUnknown(picture->width(), picture->height()));
 357
 358   GatherPixelRefDevice device(empty_bitmap, &pixel_ref_set);
 359   SkNoSaveLayerCanvas canvas(&device);
 360
 361   canvas.clipRect(SkRect::MakeWH(picture->width(), picture->height()),
 362                   SkRegion::kIntersect_Op,
 363                   false);
 364   canvas.drawPicture(picture);
 365 }
 366
 367 }  // namespace skia