src/core/SkRecordDraw.cpp - skia - Git at Google

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */

 #include "SkRecordDraw.h"
 #include "SkImage.h"
 #include "SkPatchUtils.h"

 void SkRecordDraw(const SkRecord& record,
                   SkCanvas* canvas,
                   SkPicture const* const drawablePicts[],
                   SkDrawable* const drawables[],
                   int drawableCount,
                   const SkBBoxHierarchy* bbh,
                   SkPicture::AbortCallback* callback) {
     SkAutoCanvasRestore saveRestore(canvas, true /*save now, restore at exit*/);

     if (bbh) {
         // Draw only ops that affect pixels in the canvas's current clip.
         // The SkRecord and BBH were recorded in identity space.  This canvas
         // is not necessarily in that same space.  getLocalClipBounds() returns us
         // this canvas' clip bounds transformed back into identity space, which
         // lets us query the BBH.
         SkRect query = canvas->getLocalClipBounds();

         SkTDArray<int> ops;
         bbh->search(query, &ops);

         SkRecords::Draw draw(canvas, drawablePicts, drawables, drawableCount);
         for (int i = 0; i < ops.count(); i++) {
             if (callback && callback->abort()) {
                 return;
             }
             // This visit call uses the SkRecords::Draw::operator() to call
             // methods on the |canvas|, wrapped by methods defined with the
             // DRAW() macro.
             record.visit(ops[i], draw);
         }
     } else {
         // Draw all ops.
         SkRecords::Draw draw(canvas, drawablePicts, drawables, drawableCount);
         for (int i = 0; i < record.count(); i++) {
             if (callback && callback->abort()) {
                 return;
             }
             // This visit call uses the SkRecords::Draw::operator() to call
             // methods on the |canvas|, wrapped by methods defined with the
             // DRAW() macro.
             record.visit(i, draw);
         }
     }
 }

 void SkRecordPartialDraw(const SkRecord& record, SkCanvas* canvas,
                          SkPicture const* const drawablePicts[], int drawableCount,
                          int start, int stop,
                          const SkMatrix& initialCTM) {
     SkAutoCanvasRestore saveRestore(canvas, true /*save now, restore at exit*/);

     stop = SkTMin(stop, record.count());
     SkRecords::Draw draw(canvas, drawablePicts, nullptr, drawableCount, &initialCTM);
     for (int i = start; i < stop; i++) {
         record.visit(i, draw);
     }
 }

 namespace SkRecords {

 // NoOps draw nothing.
 template <> void Draw::draw(const NoOp&) {}

 #define DRAW(T, call) template <> void Draw::draw(const T& r) { fCanvas->call; }
 DRAW(Flush, flush());
 DRAW(Restore, restore());
 DRAW(Save, save());
 DRAW(SaveLayer, saveLayer(SkCanvas::SaveLayerRec(r.bounds,
                                                  r.paint,
                                                  r.backdrop.get(),
                                                  r.clipMask.get(),
                                                  r.clipMatrix,
                                                  r.saveLayerFlags)));
 DRAW(SetMatrix, setMatrix(SkMatrix::Concat(fInitialCTM, r.matrix)));
 DRAW(Concat, concat(r.matrix));
 DRAW(Translate, translate(r.dx, r.dy));

 DRAW(ClipPath, clipPath(r.path, r.opAA.op(), r.opAA.aa()));
 DRAW(ClipRRect, clipRRect(r.rrect, r.opAA.op(), r.opAA.aa()));
 DRAW(ClipRect, clipRect(r.rect, r.opAA.op(), r.opAA.aa()));
 DRAW(ClipRegion, clipRegion(r.region, r.op));

 DRAW(DrawArc, drawArc(r.oval, r.startAngle, r.sweepAngle, r.useCenter, r.paint));
 DRAW(DrawDRRect, drawDRRect(r.outer, r.inner, r.paint));
 DRAW(DrawImage, drawImage(r.image.get(), r.left, r.top, r.paint));

 template <> void Draw::draw(const DrawImageLattice& r) {
     SkCanvas::Lattice lattice;
     lattice.fXCount = r.xCount;
     lattice.fXDivs = r.xDivs;
     lattice.fYCount = r.yCount;
     lattice.fYDivs = r.yDivs;
     lattice.fRectTypes = (0 == r.flagCount) ? nullptr : r.flags;
     lattice.fColors = (0 == r.flagCount) ? nullptr : r.colors;
     lattice.fBounds = &r.src;
     fCanvas->drawImageLattice(r.image.get(), lattice, r.dst, r.paint);
 }

 DRAW(DrawImageRect, legacy_drawImageRect(r.image.get(), r.src, r.dst, r.paint, r.constraint));
 DRAW(DrawImageNine, drawImageNine(r.image.get(), r.center, r.dst, r.paint));
 DRAW(DrawOval, drawOval(r.oval, r.paint));
 DRAW(DrawPaint, drawPaint(r.paint));
 DRAW(DrawPath, drawPath(r.path, r.paint));
 DRAW(DrawPatch, drawPatch(r.cubics, r.colors, r.texCoords, r.bmode, r.paint));
 DRAW(DrawPicture, drawPicture(r.picture.get(), &r.matrix, r.paint));
 DRAW(DrawPoints, drawPoints(r.mode, r.count, r.pts, r.paint));
 DRAW(DrawPosText, drawPosText(r.text, r.byteLength, r.pos, r.paint));
 DRAW(DrawPosTextH, drawPosTextH(r.text, r.byteLength, r.xpos, r.y, r.paint));
 DRAW(DrawRRect, drawRRect(r.rrect, r.paint));
 DRAW(DrawRect, drawRect(r.rect, r.paint));
 DRAW(DrawRegion, drawRegion(r.region, r.paint));
 DRAW(DrawText, drawText(r.text, r.byteLength, r.x, r.y, r.paint));
 DRAW(DrawTextBlob, drawTextBlob(r.blob.get(), r.x, r.y, r.paint));
 DRAW(DrawTextOnPath, drawTextOnPath(r.text, r.byteLength, r.path, &r.matrix, r.paint));
 DRAW(DrawTextRSXform, drawTextRSXform(r.text, r.byteLength, r.xforms, r.cull, r.paint));
 DRAW(DrawAtlas, drawAtlas(r.atlas.get(),
                           r.xforms, r.texs, r.colors, r.count, r.mode, r.cull, r.paint));
 DRAW(DrawVertices, drawVertices(r.vertices, r.bmode, r.paint));
 DRAW(DrawShadowRec, private_draw_shadow_rec(r.path, r.rec));
 DRAW(DrawAnnotation, drawAnnotation(r.rect, r.key.c_str(), r.value.get()));
 #undef DRAW

 template <> void Draw::draw(const DrawDrawable& r) {
     SkASSERT(r.index >= 0);
     SkASSERT(r.index < fDrawableCount);
     if (fDrawables) {
         SkASSERT(nullptr == fDrawablePicts);
         fCanvas->drawDrawable(fDrawables[r.index], r.matrix);
     } else {
         fCanvas->drawPicture(fDrawablePicts[r.index], r.matrix, nullptr);
     }
 }

 // This is an SkRecord visitor that fills an SkBBoxHierarchy.
 //
 // The interesting part here is how to calculate bounds for ops which don't
 // have intrinsic bounds.  What is the bounds of a Save or a Translate?
 //
 // We answer this by thinking about a particular definition of bounds: if I
 // don't execute this op, pixels in this rectangle might draw incorrectly.  So
 // the bounds of a Save, a Translate, a Restore, etc. are the union of the
 // bounds of Draw* ops that they might have an effect on.  For any given
 // Save/Restore block, the bounds of the Save, the Restore, and any other
 // non-drawing ("control") ops inside are exactly the union of the bounds of
 // the drawing ops inside that block.
 //
 // To implement this, we keep a stack of active Save blocks.  As we consume ops
 // inside the Save/Restore block, drawing ops are unioned with the bounds of
 // the block, and control ops are stashed away for later.  When we finish the
 // block with a Restore, our bounds are complete, and we go back and fill them
 // in for all the control ops we stashed away.
 class FillBounds : SkNoncopyable {
 public:
     FillBounds(const SkRect& cullRect, const SkRecord& record, SkRect bounds[])
         : fNumRecords(record.count())
         , fCullRect(cullRect)
         , fBounds(bounds) {
         fCTM = SkMatrix::I();

         // We push an extra save block to track the bounds of any top-level control operations.
         fSaveStack.push({ 0, Bounds::MakeEmpty(), nullptr, fCTM });
     }

     void cleanUp() {
         // If we have any lingering unpaired Saves, simulate restores to make
         // sure all ops in those Save blocks have their bounds calculated.
         while (!fSaveStack.isEmpty()) {
             this->popSaveBlock();
         }

         // Any control ops not part of any Save/Restore block draw everywhere.
         while (!fControlIndices.isEmpty()) {
             this->popControl(fCullRect);
         }
     }

     void setCurrentOp(int currentOp) { fCurrentOp = currentOp; }


     template <typename T> void operator()(const T& op) {
         this->updateCTM(op);
         this->trackBounds(op);
     }

     // In this file, SkRect are in local coordinates, Bounds are translated back to identity space.
     typedef SkRect Bounds;

     int currentOp() const { return fCurrentOp; }
     const SkMatrix& ctm() const { return fCTM; }
     const Bounds& getBounds(int index) const { return fBounds[index]; }

     // Adjust rect for all paints that may affect its geometry, then map it to identity space.
     Bounds adjustAndMap(SkRect rect, const SkPaint* paint) const {
         // Inverted rectangles really confuse our BBHs.
         rect.sort();

         // Adjust the rect for its own paint.
         if (!AdjustForPaint(paint, &rect)) {
             // The paint could do anything to our bounds.  The only safe answer is the cull.
             return fCullRect;
         }

         // Adjust rect for all the paints from the SaveLayers we're inside.
         if (!this->adjustForSaveLayerPaints(&rect)) {
             // Same deal as above.
             return fCullRect;
         }

         // Map the rect back to identity space.
         fCTM.mapRect(&rect);

         // Nothing can draw outside the cull rect.
         if (!rect.intersect(fCullRect)) {
             return Bounds::MakeEmpty();
         }

         return rect;
     }

 private:
     struct SaveBounds {
         int controlOps;        // Number of control ops in this Save block, including the Save.
         Bounds bounds;         // Bounds of everything in the block.
         const SkPaint* paint;  // Unowned.  If set, adjusts the bounds of all ops in this block.
         SkMatrix ctm;
     };

     // Only Restore, SetMatrix, Concat, and Translate change the CTM.
     template <typename T> void updateCTM(const T&) {}
     void updateCTM(const Restore& op)   { fCTM = op.matrix; }
     void updateCTM(const SetMatrix& op) { fCTM = op.matrix; }
     void updateCTM(const Concat& op)    { fCTM.preConcat(op.matrix); }
     void updateCTM(const Translate& op) { fCTM.preTranslate(op.dx, op.dy); }

     // The bounds of these ops must be calculated when we hit the Restore
     // from the bounds of the ops in the same Save block.
     void trackBounds(const Save&)          { this->pushSaveBlock(nullptr); }
     void trackBounds(const SaveLayer& op)  { this->pushSaveBlock(op.paint); }
     void trackBounds(const Restore&) { fBounds[fCurrentOp] = this->popSaveBlock(); }

     void trackBounds(const SetMatrix&)         { this->pushControl(); }
     void trackBounds(const Concat&)            { this->pushControl(); }
     void trackBounds(const Translate&)         { this->pushControl(); }
     void trackBounds(const ClipRect&)          { this->pushControl(); }
     void trackBounds(const ClipRRect&)         { this->pushControl(); }
     void trackBounds(const ClipPath&)          { this->pushControl(); }
     void trackBounds(const ClipRegion&)        { this->pushControl(); }


     // For all other ops, we can calculate and store the bounds directly now.
     template <typename T> void trackBounds(const T& op) {
         fBounds[fCurrentOp] = this->bounds(op);
         this->updateSaveBounds(fBounds[fCurrentOp]);
     }

     void pushSaveBlock(const SkPaint* paint) {
         // Starting a new Save block.  Push a new entry to represent that.
         SaveBounds sb;
         sb.controlOps = 0;
         // If the paint affects transparent black,
         // the bound shouldn't be smaller than the cull.
         sb.bounds =
             PaintMayAffectTransparentBlack(paint) ? fCullRect : Bounds::MakeEmpty();
         sb.paint = paint;
         sb.ctm = this->fCTM;

         fSaveStack.push(sb);
         this->pushControl();
     }

     static bool PaintMayAffectTransparentBlack(const SkPaint* paint) {
         if (paint) {
             // FIXME: this is very conservative
             if (paint->getImageFilter() || paint->getColorFilter()) {
                 return true;
             }

             // Unusual blendmodes require us to process a saved layer
             // even with operations outisde the clip.
             // For example, DstIn is used by masking layers.
             // https://code.google.com/p/skia/issues/detail?id=1291
             // https://crbug.com/401593
             switch (paint->getBlendMode()) {
                 // For each of the following transfer modes, if the source
                 // alpha is zero (our transparent black), the resulting
                 // blended alpha is not necessarily equal to the original
                 // destination alpha.
                 case SkBlendMode::kClear:
                 case SkBlendMode::kSrc:
                 case SkBlendMode::kSrcIn:
                 case SkBlendMode::kDstIn:
                 case SkBlendMode::kSrcOut:
                 case SkBlendMode::kDstATop:
                 case SkBlendMode::kModulate:
                     return true;
                     break;
                 default:
                     break;
             }
         }
         return false;
     }

     Bounds popSaveBlock() {
         // We're done the Save block.  Apply the block's bounds to all control ops inside it.
         SaveBounds sb;
         fSaveStack.pop(&sb);

         while (sb.controlOps --> 0) {
             this->popControl(sb.bounds);
         }

         // This whole Save block may be part another Save block.
         this->updateSaveBounds(sb.bounds);

         // If called from a real Restore (not a phony one for balance), it'll need the bounds.
         return sb.bounds;
     }

     void pushControl() {
         fControlIndices.push(fCurrentOp);
         if (!fSaveStack.isEmpty()) {
             fSaveStack.top().controlOps++;
         }
     }

     void popControl(const Bounds& bounds) {
         fBounds[fControlIndices.top()] = bounds;
         fControlIndices.pop();
     }

     void updateSaveBounds(const Bounds& bounds) {
         // If we're in a Save block, expand its bounds to cover these bounds too.
         if (!fSaveStack.isEmpty()) {
             fSaveStack.top().bounds.join(bounds);
         }
     }

     Bounds bounds(const Flush&) const { return fCullRect; }

     // FIXME: this method could use better bounds
     Bounds bounds(const DrawText&) const { return fCullRect; }

     Bounds bounds(const DrawPaint&) const { return fCullRect; }
     Bounds bounds(const NoOp&)  const { return Bounds::MakeEmpty(); }    // NoOps don't draw.

     Bounds bounds(const DrawRect& op) const { return this->adjustAndMap(op.rect, &op.paint); }
     Bounds bounds(const DrawRegion& op) const {
         SkRect rect = SkRect::Make(op.region.getBounds());
         return this->adjustAndMap(rect, &op.paint);
     }
     Bounds bounds(const DrawOval& op) const { return this->adjustAndMap(op.oval, &op.paint); }
     // Tighter arc bounds?
     Bounds bounds(const DrawArc& op) const { return this->adjustAndMap(op.oval, &op.paint); }
     Bounds bounds(const DrawRRect& op) const {
         return this->adjustAndMap(op.rrect.rect(), &op.paint);
     }
     Bounds bounds(const DrawDRRect& op) const {
         return this->adjustAndMap(op.outer.rect(), &op.paint);
     }
     Bounds bounds(const DrawImage& op) const {
         const SkImage* image = op.image.get();
         SkRect rect = SkRect::MakeXYWH(op.left, op.top, image->width(), image->height());

         return this->adjustAndMap(rect, op.paint);
     }
     Bounds bounds(const DrawImageLattice& op) const {
         return this->adjustAndMap(op.dst, op.paint);
     }
     Bounds bounds(const DrawImageRect& op) const {
         return this->adjustAndMap(op.dst, op.paint);
     }
     Bounds bounds(const DrawImageNine& op) const {
         return this->adjustAndMap(op.dst, op.paint);
     }
     Bounds bounds(const DrawPath& op) const {
         return op.path.isInverseFillType() ? fCullRect
                                            : this->adjustAndMap(op.path.getBounds(), &op.paint);
     }
     Bounds bounds(const DrawPoints& op) const {
         SkRect dst;
         dst.set(op.pts, op.count);

         // Pad the bounding box a little to make sure hairline points' bounds aren't empty.
         SkScalar stroke = SkMaxScalar(op.paint.getStrokeWidth(), 0.01f);
         dst.outset(stroke/2, stroke/2);

         return this->adjustAndMap(dst, &op.paint);
     }
     Bounds bounds(const DrawPatch& op) const {
         SkRect dst;
         dst.set(op.cubics, SkPatchUtils::kNumCtrlPts);
         return this->adjustAndMap(dst, &op.paint);
     }
     Bounds bounds(const DrawVertices& op) const {
         return this->adjustAndMap(op.vertices->bounds(), &op.paint);
     }

     Bounds bounds(const DrawAtlas& op) const {
         if (op.cull) {
             // TODO: <reed> can we pass nullptr for the paint? Isn't cull already "correct"
             // for the paint (by the caller)?
             return this->adjustAndMap(*op.cull, op.paint);
         } else {
             return fCullRect;
         }
     }

     Bounds bounds(const DrawShadowRec& op) const {
         SkRect bounds;
         SkDrawShadowMetrics::GetLocalBounds(op.path, op.rec, fCTM, &bounds);
         return this->adjustAndMap(bounds, nullptr);
     }

     Bounds bounds(const DrawPicture& op) const {
         SkRect dst = op.picture->cullRect();
         op.matrix.mapRect(&dst);
         return this->adjustAndMap(dst, op.paint);
     }

     Bounds bounds(const DrawPosText& op) const {
         const int N = op.paint.countText(op.text, op.byteLength);
         if (N == 0) {
             return Bounds::MakeEmpty();
         }

         SkRect dst;
         dst.set(op.pos, N);
         AdjustTextForFontMetrics(&dst, op.paint);
         return this->adjustAndMap(dst, &op.paint);
     }
     Bounds bounds(const DrawPosTextH& op) const {
         const int N = op.paint.countText(op.text, op.byteLength);
         if (N == 0) {
             return Bounds::MakeEmpty();
         }

         SkScalar left = op.xpos[0], right = op.xpos[0];
         for (int i = 1; i < N; i++) {
             left  = SkMinScalar(left,  op.xpos[i]);
             right = SkMaxScalar(right, op.xpos[i]);
         }
         SkRect dst = { left, op.y, right, op.y };
         AdjustTextForFontMetrics(&dst, op.paint);
         return this->adjustAndMap(dst, &op.paint);
     }
     Bounds bounds(const DrawTextOnPath& op) const {
         SkRect dst = op.path.getBounds();

         // Pad all sides by the maximum padding in any direction we'd normally apply.
         SkRect pad = { 0, 0, 0, 0};
         AdjustTextForFontMetrics(&pad, op.paint);

         // That maximum padding happens to always be the right pad today.
         SkASSERT(pad.fLeft == -pad.fRight);
         SkASSERT(pad.fTop  == -pad.fBottom);
         SkASSERT(pad.fRight > pad.fBottom);
         dst.outset(pad.fRight, pad.fRight);

         return this->adjustAndMap(dst, &op.paint);
     }

     Bounds bounds(const DrawTextRSXform& op) const {
         if (op.cull) {
             return this->adjustAndMap(*op.cull, nullptr);
         } else {
             return fCullRect;
         }
     }

     Bounds bounds(const DrawTextBlob& op) const {
         SkRect dst = op.blob->bounds();
         dst.offset(op.x, op.y);
         return this->adjustAndMap(dst, &op.paint);
     }

     Bounds bounds(const DrawDrawable& op) const {
         return this->adjustAndMap(op.worstCaseBounds, nullptr);
     }

     Bounds bounds(const DrawAnnotation& op) const {
         return this->adjustAndMap(op.rect, nullptr);
     }

     static void AdjustTextForFontMetrics(SkRect* rect, const SkPaint& paint) {
 #ifdef SK_DEBUG
         SkRect correct = *rect;
 #endif
         // crbug.com/373785 ~~> xPad = 4x yPad
         // crbug.com/424824 ~~> bump yPad from 2x text size to 2.5x
         const SkScalar yPad = 2.5f * paint.getTextSize(),
                        xPad = 4.0f * yPad;
         rect->outset(xPad, yPad);
 #ifdef SK_DEBUG
         SkPaint::FontMetrics metrics;
         paint.getFontMetrics(&metrics);
         correct.fLeft   += metrics.fXMin;
         correct.fTop    += metrics.fTop;
         correct.fRight  += metrics.fXMax;
         correct.fBottom += metrics.fBottom;
         // See skia:2862 for why we ignore small text sizes.
         SkASSERTF(paint.getTextSize() < 0.001f || rect->contains(correct),
                   "%f %f %f %f vs. %f %f %f %f\n",
                   -xPad, -yPad, +xPad, +yPad,
                   metrics.fXMin, metrics.fTop, metrics.fXMax, metrics.fBottom);
 #endif
     }

     // Returns true if rect was meaningfully adjusted for the effects of paint,
     // false if the paint could affect the rect in unknown ways.
     static bool AdjustForPaint(const SkPaint* paint, SkRect* rect) {
         if (paint) {
             if (paint->canComputeFastBounds()) {
                 *rect = paint->computeFastBounds(*rect, rect);
                 return true;
             }
             return false;
         }
         return true;
     }

     bool adjustForSaveLayerPaints(SkRect* rect, int savesToIgnore = 0) const {
         for (int i = fSaveStack.count() - 1 - savesToIgnore; i >= 0; i--) {
             SkMatrix inverse;
             if (!fSaveStack[i].ctm.invert(&inverse)) {
                 return false;
             }
             inverse.mapRect(rect);
             if (!AdjustForPaint(fSaveStack[i].paint, rect)) {
                 return false;
             }
             fSaveStack[i].ctm.mapRect(rect);
         }
         return true;
     }

     const int fNumRecords;

     // We do not guarantee anything for operations outside of the cull rect
     const SkRect fCullRect;

     // Conservative identity-space bounds for each op in the SkRecord.
     Bounds* fBounds;

     // We walk fCurrentOp through the SkRecord,
     // as we go using updateCTM() to maintain the exact CTM (fCTM).
     int fCurrentOp;
     SkMatrix fCTM;

     // Used to track the bounds of Save/Restore blocks and the control ops inside them.
     SkTDArray<SaveBounds> fSaveStack;
     SkTDArray<int>   fControlIndices;
 };

 }  // namespace SkRecords

 void SkRecordFillBounds(const SkRect& cullRect, const SkRecord& record, SkRect bounds[]) {
     SkRecords::FillBounds visitor(cullRect, record, bounds);
     for (int curOp = 0; curOp < record.count(); curOp++) {
         visitor.setCurrentOp(curOp);
         record.visit(curOp, visitor);
     }
     visitor.cleanUp();
 }
	/*
	* Copyright 2014 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/

	#include "SkRecordDraw.h"
	#include "SkImage.h"
	#include "SkPatchUtils.h"

	void SkRecordDraw(const SkRecord& record,
	SkCanvas* canvas,
	SkPicture const* const drawablePicts[],
	SkDrawable* const drawables[],
	int drawableCount,
	const SkBBoxHierarchy* bbh,
	SkPicture::AbortCallback* callback) {
	SkAutoCanvasRestore saveRestore(canvas, true /save now, restore at exit/);

	if (bbh) {
	// Draw only ops that affect pixels in the canvas's current clip.
	// The SkRecord and BBH were recorded in identity space. This canvas
	// is not necessarily in that same space. getLocalClipBounds() returns us
	// this canvas' clip bounds transformed back into identity space, which
	// lets us query the BBH.
	SkRect query = canvas->getLocalClipBounds();

	SkTDArray<int> ops;
	bbh->search(query, &ops);

	SkRecords::Draw draw(canvas, drawablePicts, drawables, drawableCount);
	for (int i = 0; i < ops.count(); i++) {
	if (callback && callback->abort()) {
	return;
	}
	// This visit call uses the SkRecords::Draw::operator() to call
	// methods on the \|canvas\|, wrapped by methods defined with the
	// DRAW() macro.
	record.visit(ops[i], draw);
	}
	} else {
	// Draw all ops.
	SkRecords::Draw draw(canvas, drawablePicts, drawables, drawableCount);
	for (int i = 0; i < record.count(); i++) {
	if (callback && callback->abort()) {
	return;
	}
	// This visit call uses the SkRecords::Draw::operator() to call
	// methods on the \|canvas\|, wrapped by methods defined with the
	// DRAW() macro.
	record.visit(i, draw);
	}
	}
	}

	void SkRecordPartialDraw(const SkRecord& record, SkCanvas* canvas,
	SkPicture const* const drawablePicts[], int drawableCount,
	int start, int stop,
	const SkMatrix& initialCTM) {
	SkAutoCanvasRestore saveRestore(canvas, true /save now, restore at exit/);

	stop = SkTMin(stop, record.count());
	SkRecords::Draw draw(canvas, drawablePicts, nullptr, drawableCount, &initialCTM);
	for (int i = start; i < stop; i++) {
	record.visit(i, draw);
	}
	}

	namespace SkRecords {

	// NoOps draw nothing.
	template <> void Draw::draw(const NoOp&) {}

	#define DRAW(T, call) template <> void Draw::draw(const T& r) { fCanvas->call; }
	DRAW(Flush, flush());
	DRAW(Restore, restore());
	DRAW(Save, save());
	DRAW(SaveLayer, saveLayer(SkCanvas::SaveLayerRec(r.bounds,
	r.paint,
	r.backdrop.get(),
	r.clipMask.get(),
	r.clipMatrix,
	r.saveLayerFlags)));
	DRAW(SetMatrix, setMatrix(SkMatrix::Concat(fInitialCTM, r.matrix)));
	DRAW(Concat, concat(r.matrix));
	DRAW(Translate, translate(r.dx, r.dy));

	DRAW(ClipPath, clipPath(r.path, r.opAA.op(), r.opAA.aa()));
	DRAW(ClipRRect, clipRRect(r.rrect, r.opAA.op(), r.opAA.aa()));
	DRAW(ClipRect, clipRect(r.rect, r.opAA.op(), r.opAA.aa()));
	DRAW(ClipRegion, clipRegion(r.region, r.op));

	DRAW(DrawArc, drawArc(r.oval, r.startAngle, r.sweepAngle, r.useCenter, r.paint));
	DRAW(DrawDRRect, drawDRRect(r.outer, r.inner, r.paint));
	DRAW(DrawImage, drawImage(r.image.get(), r.left, r.top, r.paint));

	template <> void Draw::draw(const DrawImageLattice& r) {
	SkCanvas::Lattice lattice;
	lattice.fXCount = r.xCount;
	lattice.fXDivs = r.xDivs;
	lattice.fYCount = r.yCount;
	lattice.fYDivs = r.yDivs;
	lattice.fRectTypes = (0 == r.flagCount) ? nullptr : r.flags;
	lattice.fColors = (0 == r.flagCount) ? nullptr : r.colors;
	lattice.fBounds = &r.src;
	fCanvas->drawImageLattice(r.image.get(), lattice, r.dst, r.paint);
	}

	DRAW(DrawImageRect, legacy_drawImageRect(r.image.get(), r.src, r.dst, r.paint, r.constraint));
	DRAW(DrawImageNine, drawImageNine(r.image.get(), r.center, r.dst, r.paint));
	DRAW(DrawOval, drawOval(r.oval, r.paint));
	DRAW(DrawPaint, drawPaint(r.paint));
	DRAW(DrawPath, drawPath(r.path, r.paint));
	DRAW(DrawPatch, drawPatch(r.cubics, r.colors, r.texCoords, r.bmode, r.paint));
	DRAW(DrawPicture, drawPicture(r.picture.get(), &r.matrix, r.paint));
	DRAW(DrawPoints, drawPoints(r.mode, r.count, r.pts, r.paint));
	DRAW(DrawPosText, drawPosText(r.text, r.byteLength, r.pos, r.paint));
	DRAW(DrawPosTextH, drawPosTextH(r.text, r.byteLength, r.xpos, r.y, r.paint));
	DRAW(DrawRRect, drawRRect(r.rrect, r.paint));
	DRAW(DrawRect, drawRect(r.rect, r.paint));
	DRAW(DrawRegion, drawRegion(r.region, r.paint));
	DRAW(DrawText, drawText(r.text, r.byteLength, r.x, r.y, r.paint));
	DRAW(DrawTextBlob, drawTextBlob(r.blob.get(), r.x, r.y, r.paint));
	DRAW(DrawTextOnPath, drawTextOnPath(r.text, r.byteLength, r.path, &r.matrix, r.paint));
	DRAW(DrawTextRSXform, drawTextRSXform(r.text, r.byteLength, r.xforms, r.cull, r.paint));
	DRAW(DrawAtlas, drawAtlas(r.atlas.get(),
	r.xforms, r.texs, r.colors, r.count, r.mode, r.cull, r.paint));
	DRAW(DrawVertices, drawVertices(r.vertices, r.bmode, r.paint));
	DRAW(DrawShadowRec, private_draw_shadow_rec(r.path, r.rec));
	DRAW(DrawAnnotation, drawAnnotation(r.rect, r.key.c_str(), r.value.get()));
	#undef DRAW

	template <> void Draw::draw(const DrawDrawable& r) {
	SkASSERT(r.index >= 0);
	SkASSERT(r.index < fDrawableCount);
	if (fDrawables) {
	SkASSERT(nullptr == fDrawablePicts);
	fCanvas->drawDrawable(fDrawables[r.index], r.matrix);
	} else {
	fCanvas->drawPicture(fDrawablePicts[r.index], r.matrix, nullptr);
	}
	}

	// This is an SkRecord visitor that fills an SkBBoxHierarchy.
	//
	// The interesting part here is how to calculate bounds for ops which don't
	// have intrinsic bounds. What is the bounds of a Save or a Translate?
	//
	// We answer this by thinking about a particular definition of bounds: if I
	// don't execute this op, pixels in this rectangle might draw incorrectly. So
	// the bounds of a Save, a Translate, a Restore, etc. are the union of the
	// bounds of Draw* ops that they might have an effect on. For any given
	// Save/Restore block, the bounds of the Save, the Restore, and any other
	// non-drawing ("control") ops inside are exactly the union of the bounds of
	// the drawing ops inside that block.
	//
	// To implement this, we keep a stack of active Save blocks. As we consume ops
	// inside the Save/Restore block, drawing ops are unioned with the bounds of
	// the block, and control ops are stashed away for later. When we finish the
	// block with a Restore, our bounds are complete, and we go back and fill them
	// in for all the control ops we stashed away.
	class FillBounds : SkNoncopyable {
	public:
	FillBounds(const SkRect& cullRect, const SkRecord& record, SkRect bounds[])
	: fNumRecords(record.count())
	, fCullRect(cullRect)
	, fBounds(bounds) {
	fCTM = SkMatrix::I();

	// We push an extra save block to track the bounds of any top-level control operations.
	fSaveStack.push({ 0, Bounds::MakeEmpty(), nullptr, fCTM });
	}

	void cleanUp() {
	// If we have any lingering unpaired Saves, simulate restores to make
	// sure all ops in those Save blocks have their bounds calculated.
	while (!fSaveStack.isEmpty()) {
	this->popSaveBlock();
	}

	// Any control ops not part of any Save/Restore block draw everywhere.
	while (!fControlIndices.isEmpty()) {
	this->popControl(fCullRect);
	}
	}

	void setCurrentOp(int currentOp) { fCurrentOp = currentOp; }


	template <typename T> void operator()(const T& op) {
	this->updateCTM(op);
	this->trackBounds(op);
	}

	// In this file, SkRect are in local coordinates, Bounds are translated back to identity space.
	typedef SkRect Bounds;

	int currentOp() const { return fCurrentOp; }
	const SkMatrix& ctm() const { return fCTM; }
	const Bounds& getBounds(int index) const { return fBounds[index]; }

	// Adjust rect for all paints that may affect its geometry, then map it to identity space.
	Bounds adjustAndMap(SkRect rect, const SkPaint* paint) const {
	// Inverted rectangles really confuse our BBHs.
	rect.sort();

	// Adjust the rect for its own paint.
	if (!AdjustForPaint(paint, &rect)) {
	// The paint could do anything to our bounds. The only safe answer is the cull.
	return fCullRect;
	}

	// Adjust rect for all the paints from the SaveLayers we're inside.
	if (!this->adjustForSaveLayerPaints(&rect)) {
	// Same deal as above.
	return fCullRect;
	}

	// Map the rect back to identity space.
	fCTM.mapRect(&rect);

	// Nothing can draw outside the cull rect.
	if (!rect.intersect(fCullRect)) {
	return Bounds::MakeEmpty();
	}

	return rect;
	}

	private:
	struct SaveBounds {
	int controlOps; // Number of control ops in this Save block, including the Save.
	Bounds bounds; // Bounds of everything in the block.
	const SkPaint* paint; // Unowned. If set, adjusts the bounds of all ops in this block.
	SkMatrix ctm;
	};

	// Only Restore, SetMatrix, Concat, and Translate change the CTM.
	template <typename T> void updateCTM(const T&) {}
	void updateCTM(const Restore& op) { fCTM = op.matrix; }
	void updateCTM(const SetMatrix& op) { fCTM = op.matrix; }
	void updateCTM(const Concat& op) { fCTM.preConcat(op.matrix); }
	void updateCTM(const Translate& op) { fCTM.preTranslate(op.dx, op.dy); }

	// The bounds of these ops must be calculated when we hit the Restore
	// from the bounds of the ops in the same Save block.
	void trackBounds(const Save&) { this->pushSaveBlock(nullptr); }
	void trackBounds(const SaveLayer& op) { this->pushSaveBlock(op.paint); }
	void trackBounds(const Restore&) { fBounds[fCurrentOp] = this->popSaveBlock(); }

	void trackBounds(const SetMatrix&) { this->pushControl(); }
	void trackBounds(const Concat&) { this->pushControl(); }
	void trackBounds(const Translate&) { this->pushControl(); }
	void trackBounds(const ClipRect&) { this->pushControl(); }
	void trackBounds(const ClipRRect&) { this->pushControl(); }
	void trackBounds(const ClipPath&) { this->pushControl(); }
	void trackBounds(const ClipRegion&) { this->pushControl(); }


	// For all other ops, we can calculate and store the bounds directly now.
	template <typename T> void trackBounds(const T& op) {
	fBounds[fCurrentOp] = this->bounds(op);
	this->updateSaveBounds(fBounds[fCurrentOp]);
	}

	void pushSaveBlock(const SkPaint* paint) {
	// Starting a new Save block. Push a new entry to represent that.
	SaveBounds sb;
	sb.controlOps = 0;
	// If the paint affects transparent black,
	// the bound shouldn't be smaller than the cull.
	sb.bounds =
	PaintMayAffectTransparentBlack(paint) ? fCullRect : Bounds::MakeEmpty();
	sb.paint = paint;
	sb.ctm = this->fCTM;

	fSaveStack.push(sb);
	this->pushControl();
	}

	static bool PaintMayAffectTransparentBlack(const SkPaint* paint) {
	if (paint) {
	// FIXME: this is very conservative
	if (paint->getImageFilter() \|\| paint->getColorFilter()) {
	return true;
	}

	// Unusual blendmodes require us to process a saved layer
	// even with operations outisde the clip.
	// For example, DstIn is used by masking layers.
	// https://code.google.com/p/skia/issues/detail?id=1291
	// https://crbug.com/401593
	switch (paint->getBlendMode()) {
	// For each of the following transfer modes, if the source
	// alpha is zero (our transparent black), the resulting
	// blended alpha is not necessarily equal to the original
	// destination alpha.
	case SkBlendMode::kClear:
	case SkBlendMode::kSrc:
	case SkBlendMode::kSrcIn:
	case SkBlendMode::kDstIn:
	case SkBlendMode::kSrcOut:
	case SkBlendMode::kDstATop:
	case SkBlendMode::kModulate:
	return true;
	break;
	default:
	break;
	}
	}
	return false;
	}

	Bounds popSaveBlock() {
	// We're done the Save block. Apply the block's bounds to all control ops inside it.
	SaveBounds sb;
	fSaveStack.pop(&sb);

	while (sb.controlOps --> 0) {
	this->popControl(sb.bounds);
	}

	// This whole Save block may be part another Save block.
	this->updateSaveBounds(sb.bounds);

	// If called from a real Restore (not a phony one for balance), it'll need the bounds.
	return sb.bounds;
	}

	void pushControl() {
	fControlIndices.push(fCurrentOp);
	if (!fSaveStack.isEmpty()) {
	fSaveStack.top().controlOps++;
	}
	}

	void popControl(const Bounds& bounds) {
	fBounds[fControlIndices.top()] = bounds;
	fControlIndices.pop();
	}

	void updateSaveBounds(const Bounds& bounds) {
	// If we're in a Save block, expand its bounds to cover these bounds too.
	if (!fSaveStack.isEmpty()) {
	fSaveStack.top().bounds.join(bounds);
	}
	}

	Bounds bounds(const Flush&) const { return fCullRect; }

	// FIXME: this method could use better bounds
	Bounds bounds(const DrawText&) const { return fCullRect; }

	Bounds bounds(const DrawPaint&) const { return fCullRect; }
	Bounds bounds(const NoOp&) const { return Bounds::MakeEmpty(); } // NoOps don't draw.

	Bounds bounds(const DrawRect& op) const { return this->adjustAndMap(op.rect, &op.paint); }
	Bounds bounds(const DrawRegion& op) const {
	SkRect rect = SkRect::Make(op.region.getBounds());
	return this->adjustAndMap(rect, &op.paint);
	}
	Bounds bounds(const DrawOval& op) const { return this->adjustAndMap(op.oval, &op.paint); }
	// Tighter arc bounds?
	Bounds bounds(const DrawArc& op) const { return this->adjustAndMap(op.oval, &op.paint); }
	Bounds bounds(const DrawRRect& op) const {
	return this->adjustAndMap(op.rrect.rect(), &op.paint);
	}
	Bounds bounds(const DrawDRRect& op) const {
	return this->adjustAndMap(op.outer.rect(), &op.paint);
	}
	Bounds bounds(const DrawImage& op) const {
	const SkImage* image = op.image.get();
	SkRect rect = SkRect::MakeXYWH(op.left, op.top, image->width(), image->height());

	return this->adjustAndMap(rect, op.paint);
	}
	Bounds bounds(const DrawImageLattice& op) const {
	return this->adjustAndMap(op.dst, op.paint);
	}
	Bounds bounds(const DrawImageRect& op) const {
	return this->adjustAndMap(op.dst, op.paint);
	}
	Bounds bounds(const DrawImageNine& op) const {
	return this->adjustAndMap(op.dst, op.paint);
	}
	Bounds bounds(const DrawPath& op) const {
	return op.path.isInverseFillType() ? fCullRect
	: this->adjustAndMap(op.path.getBounds(), &op.paint);
	}
	Bounds bounds(const DrawPoints& op) const {
	SkRect dst;
	dst.set(op.pts, op.count);

	// Pad the bounding box a little to make sure hairline points' bounds aren't empty.
	SkScalar stroke = SkMaxScalar(op.paint.getStrokeWidth(), 0.01f);
	dst.outset(stroke/2, stroke/2);

	return this->adjustAndMap(dst, &op.paint);
	}
	Bounds bounds(const DrawPatch& op) const {
	SkRect dst;
	dst.set(op.cubics, SkPatchUtils::kNumCtrlPts);
	return this->adjustAndMap(dst, &op.paint);
	}
	Bounds bounds(const DrawVertices& op) const {
	return this->adjustAndMap(op.vertices->bounds(), &op.paint);
	}

	Bounds bounds(const DrawAtlas& op) const {
	if (op.cull) {
	// TODO: <reed> can we pass nullptr for the paint? Isn't cull already "correct"
	// for the paint (by the caller)?
	return this->adjustAndMap(*op.cull, op.paint);
	} else {
	return fCullRect;
	}
	}

	Bounds bounds(const DrawShadowRec& op) const {
	SkRect bounds;
	SkDrawShadowMetrics::GetLocalBounds(op.path, op.rec, fCTM, &bounds);
	return this->adjustAndMap(bounds, nullptr);
	}

	Bounds bounds(const DrawPicture& op) const {
	SkRect dst = op.picture->cullRect();
	op.matrix.mapRect(&dst);
	return this->adjustAndMap(dst, op.paint);
	}

	Bounds bounds(const DrawPosText& op) const {
	const int N = op.paint.countText(op.text, op.byteLength);
	if (N == 0) {
	return Bounds::MakeEmpty();
	}

	SkRect dst;
	dst.set(op.pos, N);
	AdjustTextForFontMetrics(&dst, op.paint);
	return this->adjustAndMap(dst, &op.paint);
	}
	Bounds bounds(const DrawPosTextH& op) const {
	const int N = op.paint.countText(op.text, op.byteLength);
	if (N == 0) {
	return Bounds::MakeEmpty();
	}

	SkScalar left = op.xpos[0], right = op.xpos[0];
	for (int i = 1; i < N; i++) {
	left = SkMinScalar(left, op.xpos[i]);
	right = SkMaxScalar(right, op.xpos[i]);
	}
	SkRect dst = { left, op.y, right, op.y };
	AdjustTextForFontMetrics(&dst, op.paint);
	return this->adjustAndMap(dst, &op.paint);
	}
	Bounds bounds(const DrawTextOnPath& op) const {
	SkRect dst = op.path.getBounds();

	// Pad all sides by the maximum padding in any direction we'd normally apply.
	SkRect pad = { 0, 0, 0, 0};
	AdjustTextForFontMetrics(&pad, op.paint);

	// That maximum padding happens to always be the right pad today.
	SkASSERT(pad.fLeft == -pad.fRight);
	SkASSERT(pad.fTop == -pad.fBottom);
	SkASSERT(pad.fRight > pad.fBottom);
	dst.outset(pad.fRight, pad.fRight);

	return this->adjustAndMap(dst, &op.paint);
	}

	Bounds bounds(const DrawTextRSXform& op) const {
	if (op.cull) {
	return this->adjustAndMap(*op.cull, nullptr);
	} else {
	return fCullRect;
	}
	}

	Bounds bounds(const DrawTextBlob& op) const {
	SkRect dst = op.blob->bounds();
	dst.offset(op.x, op.y);
	return this->adjustAndMap(dst, &op.paint);
	}

	Bounds bounds(const DrawDrawable& op) const {
	return this->adjustAndMap(op.worstCaseBounds, nullptr);
	}

	Bounds bounds(const DrawAnnotation& op) const {
	return this->adjustAndMap(op.rect, nullptr);
	}

	static void AdjustTextForFontMetrics(SkRect* rect, const SkPaint& paint) {
	#ifdef SK_DEBUG
	SkRect correct = *rect;
	#endif
	// crbug.com/373785 ~~> xPad = 4x yPad
	// crbug.com/424824 ~~> bump yPad from 2x text size to 2.5x
	const SkScalar yPad = 2.5f * paint.getTextSize(),
	xPad = 4.0f * yPad;
	rect->outset(xPad, yPad);
	#ifdef SK_DEBUG
	SkPaint::FontMetrics metrics;
	paint.getFontMetrics(&metrics);
	correct.fLeft += metrics.fXMin;
	correct.fTop += metrics.fTop;
	correct.fRight += metrics.fXMax;
	correct.fBottom += metrics.fBottom;
	// See skia:2862 for why we ignore small text sizes.
	SkASSERTF(paint.getTextSize() < 0.001f \|\| rect->contains(correct),
	"%f %f %f %f vs. %f %f %f %f\n",
	-xPad, -yPad, +xPad, +yPad,
	metrics.fXMin, metrics.fTop, metrics.fXMax, metrics.fBottom);
	#endif
	}

	// Returns true if rect was meaningfully adjusted for the effects of paint,
	// false if the paint could affect the rect in unknown ways.
	static bool AdjustForPaint(const SkPaint* paint, SkRect* rect) {
	if (paint) {
	if (paint->canComputeFastBounds()) {
	rect = paint->computeFastBounds(rect, rect);
	return true;
	}
	return false;
	}
	return true;
	}

	bool adjustForSaveLayerPaints(SkRect* rect, int savesToIgnore = 0) const {
	for (int i = fSaveStack.count() - 1 - savesToIgnore; i >= 0; i--) {
	SkMatrix inverse;
	if (!fSaveStack[i].ctm.invert(&inverse)) {
	return false;
	}
	inverse.mapRect(rect);
	if (!AdjustForPaint(fSaveStack[i].paint, rect)) {
	return false;
	}
	fSaveStack[i].ctm.mapRect(rect);
	}
	return true;
	}

	const int fNumRecords;

	// We do not guarantee anything for operations outside of the cull rect
	const SkRect fCullRect;

	// Conservative identity-space bounds for each op in the SkRecord.
	Bounds* fBounds;

	// We walk fCurrentOp through the SkRecord,
	// as we go using updateCTM() to maintain the exact CTM (fCTM).
	int fCurrentOp;
	SkMatrix fCTM;

	// Used to track the bounds of Save/Restore blocks and the control ops inside them.
	SkTDArray<SaveBounds> fSaveStack;
	SkTDArray<int> fControlIndices;
	};

	} // namespace SkRecords

	void SkRecordFillBounds(const SkRect& cullRect, const SkRecord& record, SkRect bounds[]) {
	SkRecords::FillBounds visitor(cullRect, record, bounds);
	for (int curOp = 0; curOp < record.count(); curOp++) {
	visitor.setCurrentOp(curOp);
	record.visit(curOp, visitor);
	}
	visitor.cleanUp();
	}