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

src/core/SkRecordDraw.h

Index: src/core/SkRecordDraw.h
diff --git a/src/core/SkRecordDraw.h b/src/core/SkRecordDraw.h
index 75921d182fd3de1e5596114b7fce2e033cba696c..fd1302895d9640c4ac50cb3db3a30b07adc30033 100644
--- a/src/core/SkRecordDraw.h
+++ b/src/core/SkRecordDraw.h
@@ -71,6 +71,86 @@ private:
     typedef Draw INHERITED;
 };
 
+// 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 SkRecord& record, SkBBoxHierarchy* bbh);
+
+    template <typename T> void operator()(const T& op) {
+        this->updateCTM(op);
+        this->updateClipBounds(op);
+        this->trackBounds(op);
+    }
+
+protected:
+    // In FillBounds, SkRect are in local coordinates, Bounds are translated back to identity space.
+    typedef SkRect Bounds;
+
+    unsigned currentOp() const { return fCurrentOp;  }
+    const SkMatrix& ctm() const { return *fCTM; }
+    const Bounds& currentClipBounds() const { return fCurrentClipBounds; }
+
+    Bounds adjustAndMap(SkRect rect, const SkPaint* paint) const;

[robertphillips, 2014/11/03 15:38:57]

getBound is only called when processing a Restore and 'index' points to its
matching saveLayer op.

[mtklein, 2014/11/03 15:56:46]

Let's call it getBounds() for consistency with all the other names?

[robertphillips, 2014/11/03 16:49:18]

Done.

+    const Bounds& getBound(unsigned index) const { return fBounds[index]; }
+
+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.
+    };
+
+    template <typename T> void updateCTM(const T&);
+    template <typename T> void updateClipBounds(const T&);
+    template <typename T> void trackBounds(const T&);
+    template <typename T> Bounds bounds(const T&) const;
+
+    void updateClipBoundsForClipOp(const SkIRect& devBounds);
+
+    void pushSaveBlock(const SkPaint* paint);
+    static bool PaintMayAffectTransparentBlack(const SkPaint* paint);

[mtklein, 2014/11/03 15:56:46]

Let's make this guy a static function in the .cpp?

[robertphillips, 2014/11/03 16:49:18]

Done.

+    Bounds popSaveBlock();
+    void pushControl();
+    void popControl(const Bounds& bounds);
+    void updateSaveBounds(const Bounds& bounds);
+
+    static void AdjustTextForFontMetrics(SkRect* rect, const SkPaint& paint);

[mtklein, 2014/11/03 15:56:46]

These two too?

[robertphillips, 2014/11/03 16:49:18]

Done.

+    static bool AdjustForPaint(const SkPaint* paint, SkRect* rect);
+    bool adjustForSaveLayerPaints(SkRect* rect, int savesToIgnore = 0) const;
+
+    // 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;
+};
+
+
 }  // namespace SkRecords
 
 #endif//SkRecordDraw_DEFINED