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,
  34            const SkRect& rect,
  35            const SkMatrix& matrix,
  36            SkFilterQuality filter_quality) {
  37     // Only save discardable pixel refs.
  38     if (pixel_ref->getURI() &&
  39         !strcmp(pixel_ref->getURI(), kLabelDiscardable)) {
  40       PixelRefUtils::PositionPixelRef position_pixel_ref;
  41       position_pixel_ref.pixel_ref = pixel_ref;
  42       position_pixel_ref.pixel_ref_rect = rect;
  43       position_pixel_ref.matrix = matrix;
  44       position_pixel_ref.filter_quality = filter_quality;
  45       pixel_refs_->push_back(position_pixel_ref);
  46     }
  47   }
  48
  49  private:
  50   std::vector<PixelRefUtils::PositionPixelRef>* pixel_refs_;
  51 };
  52
  53 class GatherPixelRefDevice : public SkBitmapDevice {
  54  public:
  55   GatherPixelRefDevice(const SkBitmap& bm,
  56                        DiscardablePixelRefSet* pixel_ref_set)
  57       : SkBitmapDevice(bm), pixel_ref_set_(pixel_ref_set) {}
  58
  59   void drawPaint(const SkDraw& draw, const SkPaint& paint) override {
  60     SkBitmap bitmap;
  61     if (GetBitmapFromPaint(paint, &bitmap)) {
  62       SkRect clip_rect = SkRect::Make(draw.fRC->getBounds());
  63       AddBitmap(bitmap, clip_rect, *draw.fMatrix, paint.getFilterQuality());
  64     }
  65   }
  66
  67   void drawPoints(const SkDraw& draw,
  68                   SkCanvas::PointMode mode,
  69                   size_t count,
  70                   const SkPoint points[],
  71                   const SkPaint& paint) override {
  72     SkBitmap bitmap;
  73     if (!GetBitmapFromPaint(paint, &bitmap))
  74       return;
  75
  76     if (count == 0)
  77       return;
  78
  79     SkPoint min_point = points[0];
  80     SkPoint max_point = points[0];
  81     for (size_t i = 1; i < count; ++i) {
  82       const SkPoint& point = points[i];
  83       min_point.set(std::min(min_point.x(), point.x()),
  84                     std::min(min_point.y(), point.y()));
  85       max_point.set(std::max(max_point.x(), point.x()),
  86                     std::max(max_point.y(), point.y()));
  87     }
  88
  89     SkRect bounds = SkRect::MakeLTRB(
  90         min_point.x(), min_point.y(), max_point.x(), max_point.y());
  91
  92     GatherPixelRefDevice::drawRect(draw, bounds, paint);
  93   }
  94   void drawRect(const SkDraw& draw,
  95                 const SkRect& rect,
  96                 const SkPaint& paint) override {
  97     SkBitmap bitmap;
  98     if (GetBitmapFromPaint(paint, &bitmap)) {
  99       SkRect mapped_rect;
 100       draw.fMatrix->mapRect(&mapped_rect, rect);
 101       if (mapped_rect.intersect(SkRect::Make(draw.fRC->getBounds()))) {
 102         AddBitmap(bitmap, mapped_rect, *draw.fMatrix, paint.getFilterQuality());
 103       }
 104     }
 105   }
 106   void drawOval(const SkDraw& draw,
 107                 const SkRect& rect,
 108                 const SkPaint& paint) override {
 109     GatherPixelRefDevice::drawRect(draw, rect, paint);
 110   }
 111   void drawRRect(const SkDraw& draw,
 112                  const SkRRect& rect,
 113                  const SkPaint& paint) override {
 114     GatherPixelRefDevice::drawRect(draw, rect.rect(), paint);
 115   }
 116   void drawPath(const SkDraw& draw,
 117                 const SkPath& path,
 118                 const SkPaint& paint,
 119                 const SkMatrix* pre_path_matrix,
 120                 bool path_is_mutable) override {
 121     SkBitmap bitmap;
 122     if (!GetBitmapFromPaint(paint, &bitmap))
 123       return;
 124
 125     SkRect path_bounds = path.getBounds();
 126     SkRect final_rect;
 127     if (pre_path_matrix != NULL)
 128       pre_path_matrix->mapRect(&final_rect, path_bounds);
 129     else
 130       final_rect = path_bounds;
 131
 132     GatherPixelRefDevice::drawRect(draw, final_rect, paint);
 133   }
 134   void drawBitmap(const SkDraw& draw,
 135                   const SkBitmap& bitmap,
 136                   const SkMatrix& matrix,
 137                   const SkPaint& paint) override {
 138     SkMatrix total_matrix;
 139     total_matrix.setConcat(*draw.fMatrix, matrix);
 140
 141     SkRect bitmap_rect = SkRect::MakeWH(bitmap.width(), bitmap.height());
 142     SkRect mapped_rect;
 143     total_matrix.mapRect(&mapped_rect, bitmap_rect);
 144     AddBitmap(bitmap, mapped_rect, total_matrix, paint.getFilterQuality());
 145
 146     SkBitmap paint_bitmap;
 147     if (GetBitmapFromPaint(paint, &paint_bitmap)) {
 148       AddBitmap(paint_bitmap, mapped_rect, total_matrix,
 149                 paint.getFilterQuality());
 150     }
 151   }
 152   void drawBitmapRect(const SkDraw& draw,
 153                       const SkBitmap& bitmap,
 154                       const SkRect* src_or_null,
 155                       const SkRect& dst,
 156                       const SkPaint& paint,
 157                       SkCanvas::SrcRectConstraint) override {
 158     SkRect bitmap_rect = SkRect::MakeWH(bitmap.width(), bitmap.height());
 159     SkMatrix matrix;
 160     matrix.setRectToRect(bitmap_rect, dst, SkMatrix::kFill_ScaleToFit);
 161     GatherPixelRefDevice::drawBitmap(draw, bitmap, matrix, paint);
 162   }
 163   void drawSprite(const SkDraw& draw,
 164                   const SkBitmap& bitmap,
 165                   int x,
 166                   int y,
 167                   const SkPaint& paint) override {
 168     // Sprites aren't affected by current matrix, so we can't reuse drawRect.
 169     SkMatrix matrix;
 170     matrix.setTranslate(x, y);
 171
 172     SkRect bitmap_rect = SkRect::MakeWH(bitmap.width(), bitmap.height());
 173     SkRect mapped_rect;
 174     matrix.mapRect(&mapped_rect, bitmap_rect);
 175
 176     SkMatrix identity;
 177     identity.setIdentity();
 178     // Sprites aren't affected by current matrix, so use the identity matrix.
 179     AddBitmap(bitmap, mapped_rect, identity, paint.getFilterQuality());
 180     SkBitmap paint_bitmap;
 181     if (GetBitmapFromPaint(paint, &paint_bitmap))
 182       AddBitmap(paint_bitmap, mapped_rect, identity, paint.getFilterQuality());
 183   }
 184   void drawText(const SkDraw& draw,
 185                 const void* text,
 186                 size_t len,
 187                 SkScalar x,
 188                 SkScalar y,
 189                 const SkPaint& paint) override {
 190     SkBitmap bitmap;
 191     if (!GetBitmapFromPaint(paint, &bitmap))
 192       return;
 193
 194     // Math is borrowed from SkBBoxRecord
 195     SkRect bounds;
 196     paint.measureText(text, len, &bounds);
 197     SkPaint::FontMetrics metrics;
 198     paint.getFontMetrics(&metrics);
 199
 200     if (paint.isVerticalText()) {
 201       SkScalar h = bounds.fBottom - bounds.fTop;
 202       if (paint.getTextAlign() == SkPaint::kCenter_Align) {
 203         bounds.fTop -= h / 2;
 204         bounds.fBottom -= h / 2;
 205       }
 206       bounds.fBottom += metrics.fBottom;
 207       bounds.fTop += metrics.fTop;
 208     } else {
 209       SkScalar w = bounds.fRight - bounds.fLeft;
 210       if (paint.getTextAlign() == SkPaint::kCenter_Align) {
 211         bounds.fLeft -= w / 2;
 212         bounds.fRight -= w / 2;
 213       } else if (paint.getTextAlign() == SkPaint::kRight_Align) {
 214         bounds.fLeft -= w;
 215         bounds.fRight -= w;
 216       }
 217       bounds.fTop = metrics.fTop;
 218       bounds.fBottom = metrics.fBottom;
 219     }
 220
 221     SkScalar pad = (metrics.fBottom - metrics.fTop) / 2;
 222     bounds.fLeft -= pad;
 223     bounds.fRight += pad;
 224     bounds.fLeft += x;
 225     bounds.fRight += x;
 226     bounds.fTop += y;
 227     bounds.fBottom += y;
 228
 229     GatherPixelRefDevice::drawRect(draw, bounds, paint);
 230   }
 231   void drawPosText(const SkDraw& draw,
 232                    const void* text,
 233                    size_t len,
 234                    const SkScalar pos[],
 235                    int scalars_per_pos,
 236                    const SkPoint& offset,
 237                    const SkPaint& paint) override {
 238     SkBitmap bitmap;
 239     if (!GetBitmapFromPaint(paint, &bitmap))
 240       return;
 241
 242     if (len == 0)
 243       return;
 244
 245     // Similar to SkDraw asserts.
 246     SkASSERT(scalars_per_pos == 1 || scalars_per_pos == 2);
 247
 248     SkPoint min_point = SkPoint::Make(offset.x() + pos[0],
 249                                       offset.y() + (2 == scalars_per_pos ? pos[1] : 0));
 250     SkPoint max_point = min_point;
 251
 252     for (size_t i = 0; i < len; ++i) {
 253       SkScalar x = offset.x() + pos[i * scalars_per_pos];
 254       SkScalar y = offset.y() + (2 == scalars_per_pos ? pos[i * scalars_per_pos + 1] : 0);
 255
 256       min_point.set(std::min(x, min_point.x()), std::min(y, min_point.y()));
 257       max_point.set(std::max(x, max_point.x()), std::max(y, max_point.y()));
 258     }
 259
 260     SkRect bounds = SkRect::MakeLTRB(
 261         min_point.x(), min_point.y(), max_point.x(), max_point.y());
 262
 263     // Math is borrowed from SkBBoxRecord
 264     SkPaint::FontMetrics metrics;
 265     paint.getFontMetrics(&metrics);
 266
 267     bounds.fTop += metrics.fTop;
 268     bounds.fBottom += metrics.fBottom;
 269
 270     SkScalar pad = (metrics.fTop - metrics.fBottom) / 2;
 271     bounds.fLeft += pad;
 272     bounds.fRight -= pad;
 273
 274     GatherPixelRefDevice::drawRect(draw, bounds, paint);
 275   }
 276   void drawTextOnPath(const SkDraw& draw,
 277                       const void* text,
 278                       size_t len,
 279                       const SkPath& path,
 280                       const SkMatrix* matrix,
 281                       const SkPaint& paint) override {
 282     SkBitmap bitmap;
 283     if (!GetBitmapFromPaint(paint, &bitmap))
 284       return;
 285
 286     // Math is borrowed from SkBBoxRecord
 287     SkRect bounds = path.getBounds();
 288     SkPaint::FontMetrics metrics;
 289     paint.getFontMetrics(&metrics);
 290
 291     SkScalar pad = metrics.fTop;
 292     bounds.fLeft += pad;
 293     bounds.fRight -= pad;
 294     bounds.fTop += pad;
 295     bounds.fBottom -= pad;
 296
 297     GatherPixelRefDevice::drawRect(draw, bounds, paint);
 298   }
 299   void drawVertices(const SkDraw& draw,
 300                     SkCanvas::VertexMode,
 301                     int vertex_count,
 302                     const SkPoint verts[],
 303                     const SkPoint texs[],
 304                     const SkColor colors[],
 305                     SkXfermode* xmode,
 306                     const uint16_t indices[],
 307                     int index_count,
 308                     const SkPaint& paint) override {
 309     GatherPixelRefDevice::drawPoints(
 310         draw, SkCanvas::kPolygon_PointMode, vertex_count, verts, paint);
 311   }
 312   void drawDevice(const SkDraw&,
 313                   SkBaseDevice*,
 314                   int x,
 315                   int y,
 316                   const SkPaint&) override {}
 317
 318  protected:
 319   bool onReadPixels(const SkImageInfo& info,
 320                     void* pixels,
 321                     size_t rowBytes,
 322                     int x,
 323                     int y) override {
 324     return false;
 325   }
 326
 327   bool onWritePixels(const SkImageInfo& info,
 328                      const void* pixels,
 329                      size_t rowBytes,
 330                      int x,
 331                      int y) override {
 332     return false;
 333   }
 334
 335  private:
 336   DiscardablePixelRefSet* pixel_ref_set_;
 337
 338   void AddBitmap(const SkBitmap& bm,
 339                  const SkRect& rect,
 340                  const SkMatrix& matrix,
 341                  SkFilterQuality filter_quality) {
 342     SkRect canvas_rect = SkRect::MakeWH(width(), height());
 343     SkRect paint_rect = SkRect::MakeEmpty();
 344     if (paint_rect.intersect(rect, canvas_rect)) {
 345       pixel_ref_set_->Add(bm.pixelRef(), paint_rect, matrix,
 346                           filter_quality);
 347     }
 348   }
 349
 350   bool GetBitmapFromPaint(const SkPaint& paint, SkBitmap* bm) {
 351     SkShader* shader = paint.getShader();
 352     if (shader) {
 353       // Check whether the shader is a gradient in order to prevent generation
 354       // of bitmaps from gradient shaders, which implement asABitmap.
 355       if (SkShader::kNone_GradientType == shader->asAGradient(NULL))
 356         return shader->asABitmap(bm, NULL, NULL);
 357     }
 358     return false;
 359   }
 360 };
 361
 362 }  // namespace
 363
 364 void PixelRefUtils::GatherDiscardablePixelRefs(
 365     SkPicture* picture,
 366     std::vector<PositionPixelRef>* pixel_refs) {
 367   pixel_refs->clear();
 368   DiscardablePixelRefSet pixel_ref_set(pixel_refs);
 369
 370   SkRect picture_bounds = picture->cullRect();
 371   SkIRect picture_ibounds = picture_bounds.roundOut();
 372   SkBitmap empty_bitmap;
 373   empty_bitmap.setInfo(SkImageInfo::MakeUnknown(picture_ibounds.width(),
 374                                                 picture_ibounds.height()));
 375
 376   GatherPixelRefDevice device(empty_bitmap, &pixel_ref_set);
 377   SkNoSaveLayerCanvas canvas(&device);
 378
 379   // Draw the picture pinned against our top/left corner.
 380   canvas.translate(-picture_bounds.left(), -picture_bounds.top());
 381   canvas.drawPicture(picture);
 382 }
 383
 384 }  // namespace skia