Expose FillBounds to allow GrPictureUtils::CollectLayers to be layered on top of it

src/core/SkRecordDraw.cpp

 /*
  * 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 "SkPatchUtils.h"
 
@@ skipping 104 matching lines @@
 DRAW(DrawRect, drawRect(r.rect, r.paint));
 DRAW(DrawSprite, drawSprite(shallow_copy(r.bitmap), r.left, r.top, r.paint));
 DRAW(DrawText, drawText(r.text, r.byteLength, r.x, r.y, r.paint));
 DRAW(DrawTextBlob, drawTextBlob(r.blob, r.x, r.y, r.paint));
 DRAW(DrawTextOnPath, drawTextOnPath(r.text, r.byteLength, r.path, r.matrix, r.paint));
 DRAW(DrawVertices, drawVertices(r.vmode, r.vertexCount, r.vertices, r.texs, r.colors,
                                 r.xmode.get(), r.indices, r.indexCount, r.paint));
 DRAW(DrawData, drawData(r.data, r.length));
 #undef DRAW
 
-// 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, SkBBoxHierarchy* bbh) 
-        : fCullRect(cullRect)
-        , fBounds(record.count()) {
-        // Calculate bounds for all ops.  This won't go quite in order, so we'll need
-        // to store the bounds separately then feed them in to the BBH later in order.
-        fCTM = &SkMatrix::I();
-        fCurrentClipBounds = fCullRect;
-        for (fCurrentOp = 0; fCurrentOp < record.count(); fCurrentOp++) {
-            record.visit<void>(fCurrentOp, *this);
+FillBounds::FillBounds(const SkRect& cullRect, const SkRecord& record, SkBBoxHierarchy* bbh) 
+    : fNumRecords(record.count())
+    , fBBH(bbh)
+    , fCullRect(cullRect)
+    , fBounds(record.count()) {
+    // Calculate bounds for all ops.  This won't go quite in order, so we'll need
+    // to store the bounds separately then feed them in to the BBH later in order.
+    fCTM = &SkMatrix::I();
+    fCurrentClipBounds = fCullRect;
+}
+
+void FillBounds::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);
+    }
+
+    // Finally feed all stored bounds into the BBH.  They'll be returned in this order.
+    // TODO: resume use of the assert once saveLayer collection is moved into SkPicture ctor
+    //SkASSERT(bbh);
+    if (fBBH) {
+        fBBH->insert(&fBounds, fNumRecords);
+    }
+}
+
+// Only Restore and SetMatrix change the CTM.
+template <typename T> void FillBounds::updateCTM(const T&) {}
+template <> void FillBounds::updateCTM(const Restore& op)   { fCTM = &op.matrix; }
+template <> void FillBounds::updateCTM(const SetMatrix& op) { fCTM = &op.matrix; }
+
+// Most ops don't change the clip.
+template <typename T> void FillBounds::updateClipBounds(const T&) {}
+
+// Clip{Path,RRect,Rect,Region} obviously change the clip.  They all know their bounds already.
+template <> void FillBounds::updateClipBounds(const ClipPath&   op) { this->updateClipBoundsForClipOp(op.devBounds); }
+template <> void FillBounds::updateClipBounds(const ClipRRect&  op) { this->updateClipBoundsForClipOp(op.devBounds); }
+template <> void FillBounds::updateClipBounds(const ClipRect&   op) { this->updateClipBoundsForClipOp(op.devBounds); }
+template <> void FillBounds::updateClipBounds(const ClipRegion& op) { this->updateClipBoundsForClipOp(op.devBounds); }
+
+// The bounds of clip ops need to be adjusted for the paints of saveLayers they're inside.
+void FillBounds::updateClipBoundsForClipOp(const SkIRect& devBounds) {
+    Bounds clip = SkRect::Make(devBounds);
+    // We don't call adjustAndMap() because as its last step it would intersect the adjusted
+    // clip bounds with the previous clip, exactly what we can't do when the clip grows.
+    fCurrentClipBounds = this->adjustForSaveLayerPaints(&clip) ? clip : fCullRect;
+}
+
+// Restore holds the devBounds for the clip after the {save,saveLayer}/restore block completes.
+template <> void FillBounds::updateClipBounds(const Restore& op) {
+    // This is just like the clip ops above, but we need to skip the effects (if any) of our
+    // paired saveLayer (if it is one); it has not yet been popped off the save stack.  Our
+    // devBounds reflect the state of the world after the saveLayer/restore block is done,
+    // so they are not affected by the saveLayer's paint.
+    const int kSavesToIgnore = 1;
+    Bounds clip = SkRect::Make(op.devBounds);
+    fCurrentClipBounds =
+        this->adjustForSaveLayerPaints(&clip, kSavesToIgnore) ? clip : fCullRect;
+}
+
+// We also take advantage of SaveLayer bounds when present to further cut the clip down.
+template <> void FillBounds::updateClipBounds(const SaveLayer& op)  {
+    if (op.bounds) {
+        // adjustAndMap() intersects these layer bounds with the previous clip for us.
+        fCurrentClipBounds = this->adjustAndMap(*op.bounds, op.paint);
+    }
+}
+
+// The bounds of these ops must be calculated when we hit the Restore
+// from the bounds of the ops in the same Save block.
+template <> void FillBounds::trackBounds(const Save&)          { this->pushSaveBlock(NULL); }
+template <> void FillBounds::trackBounds(const SaveLayer& op)  { this->pushSaveBlock(op.paint); }
+template <> void FillBounds::trackBounds(const Restore&) { fBounds[fCurrentOp] = this->popSaveBlock(); }
+
+template <> void FillBounds::trackBounds(const SetMatrix&)         { this->pushControl(); }
+template <> void FillBounds::trackBounds(const ClipRect&)          { this->pushControl(); }
+template <> void FillBounds::trackBounds(const ClipRRect&)         { this->pushControl(); }
+template <> void FillBounds::trackBounds(const ClipPath&)          { this->pushControl(); }
+template <> void FillBounds::trackBounds(const ClipRegion&)        { this->pushControl(); }
+template <> void FillBounds::trackBounds(const PushCull&)          { this->pushControl(); }
+template <> void FillBounds::trackBounds(const PopCull&)           { this->pushControl(); }
+template <> void FillBounds::trackBounds(const BeginCommentGroup&) { this->pushControl(); }
+template <> void FillBounds::trackBounds(const AddComment&)        { this->pushControl(); }
+template <> void FillBounds::trackBounds(const EndCommentGroup&)   { this->pushControl(); }
+template <> void FillBounds::trackBounds(const DrawData&)          { this->pushControl(); }
+
+// For all other ops, we can calculate and store the bounds directly now.
+template <typename T> void FillBounds::trackBounds(const T& op) {
+    fBounds[fCurrentOp] = this->bounds(op);
+    this->updateSaveBounds(fBounds[fCurrentOp]);
+}
+
+static bool paint_may_affect_transparent_black(const SkPaint* paint) {
+    if (paint) {
+        // FIXME: this is very conservative
+        if (paint->getImageFilter() || paint->getColorFilter()) {
+            return true;
         }
 
-        // 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);
-        }
-
-        // Finally feed all stored bounds into the BBH.  They'll be returned in this order.
-        SkASSERT(bbh);
-        bbh->insert(&fBounds, record.count());
-    }
-
-    template <typename T> void operator()(const T& op) {
-        this->updateCTM(op);
-        this->updateClipBounds(op);
-        this->trackBounds(op);
-    }
-
-private:
-    // In this file, SkRect are in local coordinates, Bounds are translated back to identity space.
-    typedef SkRect Bounds;
-
-    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.
-    };
-
-    // Only Restore and SetMatrix 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; }
-
-    // Most ops don't change the clip.
-    template <typename T> void updateClipBounds(const T&) {}
-
-    // Clip{Path,RRect,Rect,Region} obviously change the clip.  They all know their bounds already.
-    void updateClipBounds(const ClipPath&   op) { this->updateClipBoundsForClipOp(op.devBounds); }
-    void updateClipBounds(const ClipRRect&  op) { this->updateClipBoundsForClipOp(op.devBounds); }
-    void updateClipBounds(const ClipRect&   op) { this->updateClipBoundsForClipOp(op.devBounds); }
-    void updateClipBounds(const ClipRegion& op) { this->updateClipBoundsForClipOp(op.devBounds); }
-
-    // The bounds of clip ops need to be adjusted for the paints of saveLayers they're inside.
-    void updateClipBoundsForClipOp(const SkIRect& devBounds) {
-        Bounds clip = SkRect::Make(devBounds);
-        // We don't call adjustAndMap() because as its last step it would intersect the adjusted
-        // clip bounds with the previous clip, exactly what we can't do when the clip grows.
-        fCurrentClipBounds = this->adjustForSaveLayerPaints(&clip) ? clip : fCullRect;
-    }
-
-    // Restore holds the devBounds for the clip after the {save,saveLayer}/restore block completes.
-    void updateClipBounds(const Restore& op) {
-        // This is just like the clip ops above, but we need to skip the effects (if any) of our
-        // paired saveLayer (if it is one); it has not yet been popped off the save stack.  Our
-        // devBounds reflect the state of the world after the saveLayer/restore block is done,
-        // so they are not affected by the saveLayer's paint.
-        const int kSavesToIgnore = 1;
-        Bounds clip = SkRect::Make(op.devBounds);
-        fCurrentClipBounds =
-            this->adjustForSaveLayerPaints(&clip, kSavesToIgnore) ? clip : fCullRect;
-    }
-
-    // We also take advantage of SaveLayer bounds when present to further cut the clip down.
-    void updateClipBounds(const SaveLayer& op)  {
-        if (op.bounds) {
-            // adjustAndMap() intersects these layer bounds with the previous clip for us.
-            fCurrentClipBounds = this->adjustAndMap(*op.bounds, op.paint);
-        }
-    }
-
-    // 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(NULL); }
-    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 ClipRect&)          { this->pushControl(); }
-    void trackBounds(const ClipRRect&)         { this->pushControl(); }
-    void trackBounds(const ClipPath&)          { this->pushControl(); }
-    void trackBounds(const ClipRegion&)        { this->pushControl(); }
-    void trackBounds(const PushCull&)          { this->pushControl(); }
-    void trackBounds(const PopCull&)           { this->pushControl(); }
-    void trackBounds(const BeginCommentGroup&) { this->pushControl(); }
-    void trackBounds(const AddComment&)        { this->pushControl(); }
-    void trackBounds(const EndCommentGroup&)   { this->pushControl(); }
-    void trackBounds(const DrawData&)          { 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 current clip bounds.
-        sb.bounds =
-            PaintMayAffectTransparentBlack(paint) ? fCurrentClipBounds : Bounds::MakeEmpty();
-        sb.paint = paint;
-
-        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 Xfermodes 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
-            SkXfermode* xfermode = paint->getXfermode();
-            SkXfermode::Mode mode;
-            // SrcOver is ok, and is also the common case with a NULL xfermode.
-            // So we should make that the fast path and bypass the mode extraction
-            // and test.
-            if (xfermode && xfermode->asMode(&mode)) {
-                switch (mode) {
-                    // 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 SkXfermode::kClear_Mode:
-                    case SkXfermode::kSrc_Mode:
-                    case SkXfermode::kSrcIn_Mode:
-                    case SkXfermode::kDstIn_Mode:
-                    case SkXfermode::kSrcOut_Mode:
-                    case SkXfermode::kDstATop_Mode:
-                    case SkXfermode::kModulate_Mode:
-                        return true;
-                        break;
-                    default:
-                        break;
-                }
+        // Unusual Xfermodes 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
+        SkXfermode* xfermode = paint->getXfermode();
+        SkXfermode::Mode mode;
+        // SrcOver is ok, and is also the common case with a NULL xfermode.
+        // So we should make that the fast path and bypass the mode extraction
+        // and test.
+        if (xfermode && xfermode->asMode(&mode)) {
+            switch (mode) {
+                // 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 SkXfermode::kClear_Mode:
+                case SkXfermode::kSrc_Mode:
+                case SkXfermode::kSrcIn_Mode:
+                case SkXfermode::kDstIn_Mode:
+                case SkXfermode::kSrcOut_Mode:
+                case SkXfermode::kDstATop_Mode:
+                case SkXfermode::kModulate_Mode:
+                    return true;
+                    break;
+                default:
+                    break;
             }
         }
+    }
+    return false;
+}
+
+void FillBounds::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 current clip bounds.
+    sb.bounds =
+        paint_may_affect_transparent_black(paint) ? fCurrentClipBounds : Bounds::MakeEmpty();
+    sb.paint = paint;
+
+    fSaveStack.push(sb);
+    this->pushControl();
+}
+
+FillBounds::Bounds FillBounds::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 FillBounds::pushControl() {
+    fControlIndices.push(fCurrentOp);
+    if (!fSaveStack.isEmpty()) {
+        fSaveStack.top().controlOps++;
+    }
+}
+
+void FillBounds::popControl(const Bounds& bounds) {
+    fBounds[fControlIndices.top()] = bounds;
+    fControlIndices.pop();
+}
+
+void FillBounds::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);
+    }
+}
+
+// FIXME: this method could use better bounds
+template <> FillBounds::Bounds FillBounds::bounds(const DrawText&) const { return fCurrentClipBounds; }
+
+template <> FillBounds::Bounds FillBounds::bounds(const Clear&) const { return fCullRect; }      // Ignores the clip.
+template <> FillBounds::Bounds FillBounds::bounds(const DrawPaint&) const { return fCurrentClipBounds; }
+template <> FillBounds::Bounds FillBounds::bounds(const NoOp&)  const { return Bounds::MakeEmpty(); }    // NoOps don't draw.
+
+template <> FillBounds::Bounds FillBounds::bounds(const DrawSprite& op) const {
+    const SkBitmap& bm = op.bitmap;
+    return Bounds::MakeXYWH(op.left, op.top, bm.width(), bm.height());  // Ignores the matrix.
+}
+
+template <> FillBounds::Bounds FillBounds::bounds(const DrawRect& op) const { return this->adjustAndMap(op.rect, &op.paint); }
+template <> FillBounds::Bounds FillBounds::bounds(const DrawOval& op) const { return this->adjustAndMap(op.oval, &op.paint); }
+template <> FillBounds::Bounds FillBounds::bounds(const DrawRRect& op) const {
+    return this->adjustAndMap(op.rrect.rect(), &op.paint);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawDRRect& op) const {
+    return this->adjustAndMap(op.outer.rect(), &op.paint);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawImage& op) const {
+    const SkImage* image = op.image;
+    SkRect rect = SkRect::MakeXYWH(op.left, op.top, image->width(), image->height());
+
+    return this->adjustAndMap(rect, op.paint);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawImageRect& op) const {
+    return this->adjustAndMap(op.dst, op.paint);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawBitmapRectToRect& op) const {
+    return this->adjustAndMap(op.dst, op.paint);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawBitmapNine& op) const {
+    return this->adjustAndMap(op.dst, op.paint);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawBitmap& op) const {
+    const SkBitmap& bm = op.bitmap;
+    return this->adjustAndMap(SkRect::MakeXYWH(op.left, op.top, bm.width(), bm.height()),
+                              op.paint);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawBitmapMatrix& op) const {
+    const SkBitmap& bm = op.bitmap;
+    SkRect dst = SkRect::MakeWH(bm.width(), bm.height());
+    op.matrix.mapRect(&dst);
+    return this->adjustAndMap(dst, op.paint);
+}
+
+template <> FillBounds::Bounds FillBounds::bounds(const DrawPath& op) const {
+    return op.path.isInverseFillType() ? fCurrentClipBounds
+                                       : this->adjustAndMap(op.path.getBounds(), &op.paint);
+}
+template <> FillBounds::Bounds FillBounds::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);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawPatch& op) const {
+    SkRect dst;
+    dst.set(op.cubics, SkPatchUtils::kNumCtrlPts);
+    return this->adjustAndMap(dst, &op.paint);
+}
+template <> FillBounds::Bounds FillBounds::bounds(const DrawVertices& op) const {
+    SkRect dst;
+    dst.set(op.vertices, op.vertexCount);
+    return this->adjustAndMap(dst, &op.paint);
+}
+
+template <> FillBounds::Bounds FillBounds::bounds(const DrawPicture& op) const {
+    SkRect dst = op.picture->cullRect();
+    if (op.matrix) {
+        op.matrix->mapRect(&dst);
+    }
+    return this->adjustAndMap(dst, op.paint);
+}
+
+static void adjust_text_for_font_metrics(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
+}
+
+template <> FillBounds::Bounds FillBounds::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);
+    adjust_text_for_font_metrics(&dst, op.paint);
+    return this->adjustAndMap(dst, &op.paint);
+}
+template <> FillBounds::Bounds FillBounds::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 };
+    adjust_text_for_font_metrics(&dst, op.paint);
+    return this->adjustAndMap(dst, &op.paint);
+}
+template <> FillBounds::Bounds FillBounds::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};
+    adjust_text_for_font_metrics(&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);
+}
+
+template <> FillBounds::Bounds FillBounds::bounds(const DrawTextBlob& op) const {
+    SkRect dst = op.blob->bounds();
+    dst.offset(op.x, op.y);
+    return this->adjustAndMap(dst, &op.paint);
+}
+
+// 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 adjust_for_paint(const SkPaint* paint, SkRect* rect) {
+    if (paint) {
+        if (paint->canComputeFastBounds()) {
+            *rect = paint->computeFastBounds(*rect, rect);
+            return true;
+        }
         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);
-        }
-    }
-
-    // FIXME: this method could use better bounds
-    Bounds bounds(const DrawText&) const { return fCurrentClipBounds; }
-
-    Bounds bounds(const Clear&) const { return fCullRect; }             // Ignores the clip.
-    Bounds bounds(const DrawPaint&) const { return fCurrentClipBounds; }
-    Bounds bounds(const NoOp&)  const { return Bounds::MakeEmpty(); }    // NoOps don't draw.
-
-    Bounds bounds(const DrawSprite& op) const {
-        const SkBitmap& bm = op.bitmap;
-        return Bounds::MakeXYWH(op.left, op.top, bm.width(), bm.height());  // Ignores the matrix.
-    }
-
-    Bounds bounds(const DrawRect& op) const { return this->adjustAndMap(op.rect, &op.paint); }
-    Bounds bounds(const DrawOval& 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;
-        SkRect rect = SkRect::MakeXYWH(op.left, op.top, image->width(), image->height());
-
-        return this->adjustAndMap(rect, op.paint);
-    }
-    Bounds bounds(const DrawImageRect& op) const {
-        return this->adjustAndMap(op.dst, op.paint);
-    }
-    Bounds bounds(const DrawBitmapRectToRect& op) const {
-        return this->adjustAndMap(op.dst, op.paint);
-    }
-    Bounds bounds(const DrawBitmapNine& op) const {
-        return this->adjustAndMap(op.dst, op.paint);
-    }
-    Bounds bounds(const DrawBitmap& op) const {
-        const SkBitmap& bm = op.bitmap;
-        return this->adjustAndMap(SkRect::MakeXYWH(op.left, op.top, bm.width(), bm.height()),
-                                  op.paint);
-    }
-    Bounds bounds(const DrawBitmapMatrix& op) const {
-        const SkBitmap& bm = op.bitmap;
-        SkRect dst = SkRect::MakeWH(bm.width(), bm.height());
-        op.matrix.mapRect(&dst);
-        return this->adjustAndMap(dst, op.paint);
-    }
-
-    Bounds bounds(const DrawPath& op) const {
-        return op.path.isInverseFillType() ? fCurrentClipBounds
-                                           : 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 {
-        SkRect dst;
-        dst.set(op.vertices, op.vertexCount);
-        return this->adjustAndMap(dst, &op.paint);
-    }
-
-    Bounds bounds(const DrawPicture& op) const {
-        SkRect dst = op.picture->cullRect();
-        if (op.matrix) {
-            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 DrawTextBlob& op) const {
-        SkRect dst = op.blob->bounds();
-        dst.offset(op.x, op.y);
-        return this->adjustAndMap(dst, &op.paint);
-    }
-
-    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 true;
+}
+
+bool FillBounds::adjustForSaveLayerPaints(SkRect* rect, int savesToIgnore) const {
+    for (int i = fSaveStack.count() - 1 - savesToIgnore; i >= 0; i--) {
+        if (!adjust_for_paint(fSaveStack[i].paint, rect)) {
             return false;
         }
-        return true;
-    }
-
-    bool adjustForSaveLayerPaints(SkRect* rect, int savesToIgnore = 0) const {
-        for (int i = fSaveStack.count() - 1 - savesToIgnore; i >= 0; i--) {
-            if (!AdjustForPaint(fSaveStack[i].paint, rect)) {
-                return false;
-            }
-        }
-        return true;
-    }
-
-    // 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 current clip.
-            return fCurrentClipBounds;
-        }
-
-        // Adjust rect for all the paints from the SaveLayers we're inside.
-        if (!this->adjustForSaveLayerPaints(&rect)) {
-            // Same deal as above.
-            return fCurrentClipBounds;
-        }
-
-        // Map the rect back to identity space.
-        fCTM->mapRect(&rect);
-
-        // Nothing can draw outside the current clip.
-        // (Only bounded ops call into this method, so oddballs like Clear don't matter here.)
-        rect.intersect(fCurrentClipBounds);
-        return rect;
-    }
-
-    // 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.
-    SkAutoTMalloc<Bounds> fBounds;
-
-    // We walk fCurrentOp through the SkRecord, as we go using updateCTM()
-    // and updateClipBounds() to maintain the exact CTM (fCTM) and conservative
-    // identity-space bounds of the current clip (fCurrentClipBounds).
-    unsigned fCurrentOp;
-    const SkMatrix* fCTM;
-    Bounds fCurrentClipBounds;
-
-    // Used to track the bounds of Save/Restore blocks and the control ops inside them.
-    SkTDArray<SaveBounds> fSaveStack;
-    SkTDArray<unsigned>   fControlIndices;
-};
+    }
+    return true;
+}
+
+// Adjust rect for all paints that may affect its geometry, then map it to identity space.
+FillBounds::Bounds FillBounds::adjustAndMap(SkRect rect, const SkPaint* paint) const {
+    // Inverted rectangles really confuse our BBHs.
+    rect.sort();
+
+    // Adjust the rect for its own paint.
+    if (!adjust_for_paint(paint, &rect)) {
+        // The paint could do anything to our bounds.  The only safe answer is the current clip.
+        return fCurrentClipBounds;
+    }
+
+    // Adjust rect for all the paints from the SaveLayers we're inside.
+    if (!this->adjustForSaveLayerPaints(&rect)) {
+        // Same deal as above.
+        return fCurrentClipBounds;
+    }
+
+    // Map the rect back to identity space.
+    fCTM->mapRect(&rect);
+
+    // Nothing can draw outside the current clip.
+    // (Only bounded ops call into this method, so oddballs like Clear don't matter here.)
+    rect.intersect(fCurrentClipBounds);
+    return rect;
+}
 
 }  // namespace SkRecords
 
 void SkRecordFillBounds(const SkRect& cullRect, const SkRecord& record, SkBBoxHierarchy* bbh) {
-    SkRecords::FillBounds(cullRect, record, bbh);
-}
+    SkRecords::FillBounds visitor(cullRect, record, bbh);
+
+    for (unsigned curOp = 0; curOp < record.count(); curOp++) {
+        visitor.setCurrentOp(curOp);
+        record.visit<void>(curOp, visitor);
+    }
+
+    visitor.cleanUp();
+}