Added bound computation to SkClipStack

http://codereview.appspot.com/6419048/

This will require re-baselining of complexclip* and filltypespersp

git-svn-id: http://skia.googlecode.com/svn/trunk@4730 2bbb7eff-a529-9590-31e7-b0007b416f81

diff --git a/include/core/SkClipStack.h b/include/core/SkClipStack.h
index daeb82629a66e52920a533ff23823c8aaef7f956..fbdcb36c844fcd8ed60abee5fefe4e32c875bc77 100644 (file)
--- a/include/core/SkClipStack.h
+++ b/include/core/SkClipStack.h
@@ -30,6 +30,27 @@ public:
     void save();
     void restore();
 
+    enum BoundsType {
+        // The bounding box contains all the pixels that can be written to
+        kNormal_BoundsType,
+        // The bounding box contains all the pixels that cannot be written to.
+        // The real bound extends out to infinity and all the pixels outside
+        // of the bound can be written to. Note that some of the pixels inside
+        // the bound may also be writeable but all pixels that cannot be 
+        // written to are guaranteed to be inside.
+        kInsideOut_BoundsType
+    };
+
+    /**
+     * getBounds places the current finite bound in its first parameter. In its
+     * second, it indicates which kind of bound is being returned. If 
+     * 'finiteBound' is a normal bounding box then it encloses are writeable
+     * pixels. If 'finiteBound' is an inside out bounding box then it 
+     * encloses all the un-writeable pixels and the true/normal bound is the
+     * infinite plane.
+     */
+    void getBounds(SkRect* finiteBound, BoundsType* boundType) const;
+
     void clipDevRect(const SkIRect& ir, SkRegion::Op op) {
         SkRect r;
         r.set(ir);
@@ -135,6 +156,22 @@ public:
         typedef Iter INHERITED;
     };
 
+    /**
+     * GetConservativeBounds returns a conservative bound of the current clip. 
+     * Since this could be the infinite plane (if inverse fills were involved) the 
+     * maxWidth and maxHeight parameters can be used to limit the returned bound 
+     * to the expected drawing area. Similarly, the offsetX and offsetY parameters
+     * allow the caller to offset the returned bound to account for translated 
+     * drawing areas (i.e., those resulting from a saveLayer). For finite bounds,
+     * the translation (+offsetX, +offsetY) is applied before the clamp to the 
+     * maximum rectangle: [0,maxWidth) x [0,maxHeight).
+     */
+    void getConservativeBounds(int offsetX,
+                               int offsetY,
+                               int maxWidth,
+                               int maxHeight,
+                               SkRect* bounds) const;
+
 private:
     friend class Iter;
 

diff --git a/src/core/SkClipStack.cpp b/src/core/SkClipStack.cpp
index 4212ba56e6bc01e2529cccf92bd3a4e0a32ddbc3..2676f3b07883b924b7c1af3ca3be2e072eede501 100644 (file)
--- a/src/core/SkClipStack.cpp
+++ b/src/core/SkClipStack.cpp
@@ -9,6 +9,7 @@
 #include "SkPath.h"
 #include <new>
 
+
 struct SkClipStack::Rec {
     enum State {
         kEmpty_State,
@@ -23,6 +24,22 @@ struct SkClipStack::Rec {
     State           fState;
     bool            fDoAA;
 
+    // fFiniteBoundType and fFiniteBound are used to incrementally update
+    // the clip stack's bound. When fFiniteBoundType is kNormal_BoundsType, 
+    // fFiniteBound represents the  conservative bounding box of the pixels 
+    // that aren't clipped (i.e., any pixels that can be drawn to are inside 
+    // the bound). When fFiniteBoundType is kInsideOut_BoundsType (which occurs 
+    // when a clip is inverse filled), fFiniteBound represents the 
+    // conservative bounding box of the pixels that _are_ clipped (i.e., any 
+    // pixels that cannot be drawn to are inside the bound). When 
+    // fFiniteBoundType is kInsideOut_BoundsType the actual bound is
+    // the infinite plane. This behavior of fFiniteBoundType and
+    // fFiniteBound is required so that we can capture the cancelling out
+    // of the extensions to infinity when two inverse filled clips are
+    // Booleaned together.
+    SkClipStack::BoundsType fFiniteBoundType;
+    SkRect                 fFiniteBound;
+
     Rec(int saveCount, const SkRect& rect, SkRegion::Op op, bool doAA) : fRect(rect) {
         fSaveCount = saveCount;
         fOp = op;
@@ -72,6 +89,271 @@ struct SkClipStack::Rec {
                 SkRegion::kIntersect_Op == fOp &&
                 SkRegion::kIntersect_Op == op;
     }
+
+    /**
+     * The different combination of fill & inverse fill when combining
+     * bounding boxes
+     */ 
+    enum FillCombo {
+        kPrev_Cur_FillCombo,
+        kPrev_InvCur_FillCombo,
+        kInvPrev_Cur_FillCombo,
+        kInvPrev_InvCur_FillCombo
+    };
+
+    // a mirror of CombineBoundsRevDiff
+    void CombineBoundsDiff(FillCombo combination, const SkRect& prevFinite) {
+        switch (combination) {
+            case kInvPrev_InvCur_FillCombo:
+                // In this case the only pixels that can remain set
+                // are inside the current clip rect since the extensions
+                // to infinity of both clips cancel out and whatever
+                // is outside of the current clip is removed
+                fFiniteBoundType = kNormal_BoundsType;
+                break;
+            case kInvPrev_Cur_FillCombo:
+                // In this case the current op is finite so the only pixels
+                // that aren't set are whatever isn't set in the previous
+                // clip and whatever this clip carves out
+                fFiniteBound.join(prevFinite);
+                fFiniteBoundType = kInsideOut_BoundsType;
+                break;
+            case kPrev_InvCur_FillCombo:
+                // In this case everything outside of this clip's bound
+                // is erased, so the only pixels that can remain set 
+                // occur w/in the intersection of the two finite bounds
+                if (!fFiniteBound.intersect(prevFinite)) {
+                    fFiniteBound.setEmpty();
+                }
+                fFiniteBoundType = kNormal_BoundsType;
+                break;
+            case kPrev_Cur_FillCombo:
+                // The most conservative result bound is that of the 
+                // prior clip. This could be wildly incorrect if the 
+                // second clip either exactly matches the first clip 
+                // (which should yield the empty set) or reduces the
+                // size of the prior bound (e.g., if the second clip 
+                // exactly matched the bottom half of the prior clip).
+                // We ignore these two possibilities.
+                fFiniteBound = prevFinite;
+                break;
+            default:
+                SkDEBUGFAIL("SkClipStack::Rec::CombineBoundsDiff Invalid fill combination");
+                break;
+        }
+    }
+
+    void CombineBoundsXOR(int combination, const SkRect& prevFinite) {
+
+        switch (combination) {
+            case kInvPrev_Cur_FillCombo:       // fall through
+            case kPrev_InvCur_FillCombo:
+                // With only one of the clips inverted the result will always
+                // extend to infinity. The only pixels that may be un-writeable
+                // lie within the union of the two finite bounds
+                fFiniteBound.join(prevFinite);
+                fFiniteBoundType = kInsideOut_BoundsType;
+                break;
+            case kInvPrev_InvCur_FillCombo:
+                // The only pixels that can survive are within the 
+                // union of the two bounding boxes since the extensions
+                // to infinity of both clips cancel out
+                // fall through!
+            case kPrev_Cur_FillCombo:
+                // The most conservative bound for xor is the 
+                // union of the two bounds. If the two clips exactly overlapped
+                // the xor could yield the empty set. Similarly the xor 
+                // could reduce the size of the original clip's bound (e.g., 
+                // if the second clip exactly matched the bottom half of the 
+                // first clip). We ignore these two cases.
+                fFiniteBound.join(prevFinite);
+                fFiniteBoundType = kNormal_BoundsType;
+                break;
+            default:
+                SkDEBUGFAIL("SkClipStack::Rec::CombineBoundsXOR Invalid fill combination");
+                break;
+        }
+    }
+
+    // a mirror of CombineBoundsIntersection
+    void CombineBoundsUnion(int combination, const SkRect& prevFinite) {
+
+        switch (combination) {
+            case kInvPrev_InvCur_FillCombo:
+                if (!fFiniteBound.intersect(prevFinite)) {
+                    fFiniteBound.setEmpty();
+                }
+                fFiniteBoundType = kInsideOut_BoundsType;
+                break;
+            case kInvPrev_Cur_FillCombo:
+                // The only pixels that won't be drawable are inside
+                // the prior clip's finite bound
+                fFiniteBound = prevFinite;
+                fFiniteBoundType = kInsideOut_BoundsType;
+                break;
+            case kPrev_InvCur_FillCombo:
+                // The only pixels that won't be drawable are inside
+                // this clip's finite bound
+                break;
+            case kPrev_Cur_FillCombo:
+                fFiniteBound.join(prevFinite);
+                break;
+            default:
+                SkDEBUGFAIL("SkClipStack::Rec::CombineBoundsUnion Invalid fill combination");
+                break;
+        }
+    }
+
+    // a mirror of CombineBoundsUnion
+    void CombineBoundsIntersection(int combination, const SkRect& prevFinite) {
+
+        switch (combination) {
+            case kInvPrev_InvCur_FillCombo:
+                // The only pixels that aren't writable in this case 
+                // occur in the union of the two finite bounds
+                fFiniteBound.join(prevFinite);
+                fFiniteBoundType = kInsideOut_BoundsType;
+                break;
+            case kInvPrev_Cur_FillCombo:      
+                // In this case the only pixels that will remain writeable
+                // are within the current clip
+                break;
+            case kPrev_InvCur_FillCombo:
+                // In this case the only pixels that will remain writeable
+                // are with the previous clip
+                fFiniteBound = prevFinite;
+                fFiniteBoundType = kNormal_BoundsType;
+                break;
+            case kPrev_Cur_FillCombo:
+                if (!fFiniteBound.intersect(prevFinite)) {
+                    fFiniteBound.setEmpty();
+                }
+                break;
+            default:
+                SkDEBUGFAIL("SkClipStack::Rec::CombineBoundsIntersection Invalid fill combination");
+                break;
+        }
+    }
+
+    // a mirror of CombineBoundsDiff
+    void CombineBoundsRevDiff(int combination, const SkRect& prevFinite) {
+
+        switch (combination) {
+            case kInvPrev_InvCur_FillCombo:
+                // The only pixels that can survive are in the 
+                // previous bound since the extensions to infinity in
+                // both clips cancel out
+                fFiniteBound = prevFinite;
+                fFiniteBoundType = kNormal_BoundsType;
+                break;
+            case kInvPrev_Cur_FillCombo:
+                if (!fFiniteBound.intersect(prevFinite)) {
+                    fFiniteBound.setEmpty();
+                }
+                fFiniteBoundType = kNormal_BoundsType;
+                break;
+            case kPrev_InvCur_FillCombo:
+                fFiniteBound.join(prevFinite);
+                fFiniteBoundType = kInsideOut_BoundsType;
+                break;
+            case kPrev_Cur_FillCombo:
+                // Fall through - as with the kDifference_Op case, the 
+                // most conservative result bound is the bound of the
+                // current clip. The prior clip could reduce the size of this 
+                // bound (as in the kDifference_Op case) but we are ignoring 
+                // those cases.
+                break;
+            default:
+                SkDEBUGFAIL("SkClipStack::Rec::CombineBoundsRevDiff Invalid fill combination");
+                break;
+        }
+    }
+
+    void updateBound(const Rec* prior) {
+
+        // First, optimistically update the current Rec's bound information 
+        // with the current clip's bound
+        if (kRect_State == fState) {
+            fFiniteBound = fRect;
+            fFiniteBoundType = kNormal_BoundsType;
+        } else {
+            fFiniteBound = fPath.getBounds();
+
+            if (fPath.isInverseFillType()) {
+                fFiniteBoundType = kInsideOut_BoundsType;
+            } else {
+                fFiniteBoundType = kNormal_BoundsType;
+            }
+        }
+
+        if (!fDoAA) {
+            // Here we mimic a non-anti-aliased scanline system. If there is
+            // no anti-aliasing we can integerize the bounding box to exclude
+            // fractional parts that won't be rendered.
+            // Note: the left edge is handled slightly differently below. We
+            // are a bit more generous in the rounding since we don't want to
+            // risk missing the left pixels when fLeft is very close to .5
+            fFiniteBound.set(SkIntToScalar(SkScalarFloorToInt(fFiniteBound.fLeft+0.45f)), 
+                             SkIntToScalar(SkScalarRound(fFiniteBound.fTop)), 
+                             SkIntToScalar(SkScalarRound(fFiniteBound.fRight)), 
+                             SkIntToScalar(SkScalarRound(fFiniteBound.fBottom)));
+        }
+
+        // Now set up the previous Rec's bound information taking into
+        // account that there may be no previous clip
+        SkRect prevFinite;
+        SkClipStack::BoundsType prevType;
+
+        if (NULL == prior) {
+            // no prior clip means the entire plane is writable
+            prevFinite.setEmpty();   // there are no pixels that cannot be drawn to
+            prevType = kInsideOut_BoundsType;
+        } else {
+            prevFinite = prior->fFiniteBound;
+            prevType = prior->fFiniteBoundType;
+        }
+
+        FillCombo combination = kPrev_Cur_FillCombo;
+        if (kInsideOut_BoundsType == fFiniteBoundType) {
+            combination = (FillCombo) (combination | 0x01);
+        }
+        if (kInsideOut_BoundsType == prevType) {
+            combination = (FillCombo) (combination | 0x02);
+        }
+
+        SkASSERT(kInvPrev_InvCur_FillCombo == combination || 
+                 kInvPrev_Cur_FillCombo == combination ||
+                 kPrev_InvCur_FillCombo == combination || 
+                 kPrev_Cur_FillCombo == combination);
+
+        // Now integrate with clip with the prior clips
+        switch (fOp) {
+            case SkRegion::kDifference_Op:
+                this->CombineBoundsDiff(combination, prevFinite);
+                break;
+            case SkRegion::kXOR_Op:
+                this->CombineBoundsXOR(combination, prevFinite);
+                break;
+            case SkRegion::kUnion_Op:
+                this->CombineBoundsUnion(combination, prevFinite);
+                break;
+            case SkRegion::kIntersect_Op:
+                this->CombineBoundsIntersection(combination, prevFinite);
+                break;
+            case SkRegion::kReverseDifference_Op:
+                this->CombineBoundsRevDiff(combination, prevFinite);
+                break;
+            case SkRegion::kReplace_Op:
+                // Replace just ignores everything prior
+                // The current clip's bound information is already filled in
+                // so nothing to do
+                break;
+            default:
+                SkDebugf("SkRegion::Op error/n");
+                SkASSERT(0);
+                break;
+        }
+    }
 };
 
 SkClipStack::SkClipStack() : fDeque(sizeof(Rec)) {
@@ -95,8 +377,8 @@ SkClipStack& SkClipStack::operator=(const SkClipStack& b) {
     fSaveCount = b.fSaveCount;
     SkDeque::F2BIter recIter(b.fDeque);
     for (const Rec* rec = (const Rec*)recIter.next();
-            rec != NULL;
-            rec = (const Rec*)recIter.next()) {
+         rec != NULL;
+         rec = (const Rec*)recIter.next()) {
         new (fDeque.push_back()) Rec(*rec);
     }
 
@@ -150,26 +432,52 @@ void SkClipStack::restore() {
     }
 }
 
+void SkClipStack::getBounds(SkRect* finiteBound, BoundsType* boundType) const {
+    SkASSERT(NULL != finiteBound && NULL != boundType);
+
+    Rec* rec = (Rec*)fDeque.back();
+
+    if (NULL == rec) {
+        // the clip is wide open - the infinite plane w/ no pixels un-writeable
+        finiteBound->setEmpty();
+        *boundType = kInsideOut_BoundsType;
+        return;
+    }
+
+    *finiteBound = rec->fFiniteBound;
+    *boundType = rec->fFiniteBoundType;
+}
+
 void SkClipStack::clipDevRect(const SkRect& rect, SkRegion::Op op, bool doAA) {
     Rec* rec = (Rec*)fDeque.back();
     if (rec && rec->canBeIntersected(fSaveCount, op)) {
         switch (rec->fState) {
             case Rec::kEmpty_State:
+                SkASSERT(rec->fFiniteBound.isEmpty());
+                SkASSERT(kNormal_BoundsType == rec->fFiniteBoundType);
                 return;
             case Rec::kRect_State:
                 if (!rec->fRect.intersect(rect)) {
                     rec->fState = Rec::kEmpty_State;
+                    rec->fFiniteBound.setEmpty();
+                    rec->fFiniteBoundType = kNormal_BoundsType;
+                    return;
                 }
+
+                rec->updateBound(NULL);
                 return;
             case Rec::kPath_State:
                 if (!SkRect::Intersects(rec->fPath.getBounds(), rect)) {
                     rec->fState = Rec::kEmpty_State;
+                    rec->fFiniteBound.setEmpty();
+                    rec->fFiniteBoundType = kNormal_BoundsType;
                     return;
                 }
                 break;
         }
     }
     new (fDeque.push_back()) Rec(fSaveCount, rect, op, doAA);
+    ((Rec*) fDeque.back())->updateBound(rec);
 }
 
 void SkClipStack::clipDevPath(const SkPath& path, SkRegion::Op op, bool doAA) {
@@ -182,22 +490,29 @@ void SkClipStack::clipDevPath(const SkPath& path, SkRegion::Op op, bool doAA) {
         const SkRect& pathBounds = path.getBounds();
         switch (rec->fState) {
             case Rec::kEmpty_State:
+                SkASSERT(rec->fFiniteBound.isEmpty());
+                SkASSERT(kNormal_BoundsType == rec->fFiniteBoundType);
                 return;
             case Rec::kRect_State:
                 if (!SkRect::Intersects(rec->fRect, pathBounds)) {
                     rec->fState = Rec::kEmpty_State;
+                    rec->fFiniteBound.setEmpty();
+                    rec->fFiniteBoundType = kNormal_BoundsType;
                     return;
                 }
                 break;
             case Rec::kPath_State:
                 if (!SkRect::Intersects(rec->fPath.getBounds(), pathBounds)) {
                     rec->fState = Rec::kEmpty_State;
+                    rec->fFiniteBound.setEmpty();
+                    rec->fFiniteBoundType = kNormal_BoundsType;
                     return;
                 }
                 break;
         }
     }
     new (fDeque.push_back()) Rec(fSaveCount, path, op, doAA);
+    ((Rec*) fDeque.back())->updateBound(rec);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -306,3 +621,29 @@ void SkClipStack::Iter::reset(const SkClipStack& stack, IterStart startLoc) {
     fStack = &stack;
     fIter.reset(stack.fDeque, static_cast<SkDeque::Iter::IterStart>(startLoc));
 }
+
+// helper method
+void SkClipStack::getConservativeBounds(int offsetX,
+                                        int offsetY,
+                                        int maxWidth,
+                                        int maxHeight,
+                                        SkRect* bounds) const {
+    SkASSERT(NULL != bounds);
+
+    bounds->setLTRB(0, 0, 
+                    SkIntToScalar(maxWidth), SkIntToScalar(maxHeight));
+
+    SkRect temp;
+    SkClipStack::BoundsType boundType;
+    
+    this->getBounds(&temp, &boundType);
+    if (SkClipStack::kInsideOut_BoundsType == boundType) {
+        return;
+    }
+
+    temp.offset(SkIntToScalar(offsetX), SkIntToScalar(offsetY));
+
+    if (!bounds->intersect(temp)) {
+        bounds->setEmpty();
+    }
+}

diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index bd92089cc7f80e7ab4240897905426bc3792f597..1da5a0a0a492df5a68facfc22293d74597877a93 100644 (file)
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -361,22 +361,60 @@ void SkGpuDevice::onDetachFromCanvas() {
     fClipStack = NULL;
 }
 
+#ifdef SK_DEBUG
+static void check_bounds(const SkClipStack& clipStack,
+                         const SkRegion& clipRegion,
+                         const SkIPoint& origin,
+                         int renderTargetWidth,
+                         int renderTargetHeight) {
+
+    SkIRect bound;
+    SkClipStack::BoundsType boundType;
+    SkRect temp;
+
+    bound.setLTRB(0, 0, renderTargetWidth, renderTargetHeight);
+
+    clipStack.getBounds(&temp, &boundType);
+    if (SkClipStack::kNormal_BoundsType == boundType) {
+        SkIRect temp2;
+
+        temp.roundOut(&temp2);
+
+        temp2.offset(-origin.fX, -origin.fY);
+
+        if (!bound.intersect(temp2)) {
+            bound.setEmpty();
+        }
+    }
+
+//    GrAssert(bound.contains(clipRegion.getBounds()));
+}
+#endif
+
 ///////////////////////////////////////////////////////////////////////////////
 
 static void convert_matrixclip(GrContext* context, const SkMatrix& matrix,
                                const SkClipStack& clipStack,
                                const SkRegion& clipRegion,
-                               const SkIPoint& origin) {
+                               const SkIPoint& origin,
+                               int renderTargetWidth, int renderTargetHeight) {
     context->setMatrix(matrix);
 
     SkGrClipIterator iter;
     iter.reset(clipStack);
-    const SkIRect& skBounds = clipRegion.getBounds();
-    GrRect bounds;
-    bounds.setLTRB(GrIntToScalar(skBounds.fLeft),
-                   GrIntToScalar(skBounds.fTop),
-                   GrIntToScalar(skBounds.fRight),
-                   GrIntToScalar(skBounds.fBottom));
+
+#ifdef SK_DEBUG
+    check_bounds(clipStack, clipRegion, origin,
+                 renderTargetWidth, renderTargetHeight);
+#endif
+
+    SkRect bounds;
+    clipStack.getConservativeBounds(-origin.fX,
+                                    -origin.fY,
+                                    renderTargetWidth,
+                                    renderTargetHeight,
+                                    &bounds);
+
     GrClip grc(&iter, GrIntToScalar(-origin.x()), GrIntToScalar(-origin.y()),
                bounds);
     context->setClip(grc);
@@ -392,8 +430,10 @@ void SkGpuDevice::prepareRenderTarget(const SkDraw& draw) {
 
         fContext->setRenderTarget(fRenderTarget);
         SkASSERT(draw.fClipStack && draw.fClipStack == fClipStack);
+
         convert_matrixclip(fContext, *draw.fMatrix,
-                           *fClipStack, *draw.fClip, this->getOrigin());
+                           *fClipStack, *draw.fClip, this->getOrigin(),
+                           fRenderTarget->width(), fRenderTarget->height());
         fNeedPrepareRenderTarget = false;
     }
 }
@@ -413,7 +453,8 @@ void SkGpuDevice::gainFocus(const SkMatrix& matrix, const SkRegion& clip) {
 
     this->INHERITED::gainFocus(matrix, clip);
 
-    convert_matrixclip(fContext, matrix, *fClipStack, clip, this->getOrigin());
+    convert_matrixclip(fContext, matrix, *fClipStack, clip, this->getOrigin(),
+                       fRenderTarget->width(), fRenderTarget->height());
 
     DO_DEFERRED_CLEAR;
 }

diff --git a/tests/ClipStackTest.cpp b/tests/ClipStackTest.cpp
index 85a999797ae57107c18ae850aeca382decbe66a1..e5001f11003a13d3a454abae653ee12be2c4e615 100644 (file)
--- a/tests/ClipStackTest.cpp
+++ b/tests/ClipStackTest.cpp
@@ -183,6 +183,87 @@ static void test_iterators(skiatest::Reporter* reporter) {
     }
 }
 
+static void test_bounds(skiatest::Reporter* reporter) {
+
+    static const int gNumCases = 20;
+    static const SkRect gAnswerRectsBW[gNumCases] = {
+        // A op B
+        { 40, 40, 50, 50 },
+        { 10, 10, 50, 50 },
+        { 10, 10, 80, 80 },
+        { 10, 10, 80, 80 },
+        { 40, 40, 80, 80 },
+
+        // invA op B
+        { 40, 40, 80, 80 },
+        { 0, 0, 100, 100 },
+        { 0, 0, 100, 100 },
+        { 0, 0, 100, 100 },
+        { 40, 40, 50, 50 },
+
+        // A op invB
+        { 10, 10, 50, 50 },
+        { 40, 40, 50, 50 },
+        { 0, 0, 100, 100 },
+        { 0, 0, 100, 100 },
+        { 0, 0, 100, 100 },
+
+        // invA op invB
+        { 0, 0, 100, 100 },
+        { 40, 40, 80, 80 },
+        { 0, 0, 100, 100 },
+        { 10, 10, 80, 80 },
+        { 10, 10, 50, 50 },
+    };
+
+    static const SkRegion::Op gOps[] = {
+        SkRegion::kIntersect_Op,
+        SkRegion::kDifference_Op,
+        SkRegion::kUnion_Op,
+        SkRegion::kXOR_Op,
+        SkRegion::kReverseDifference_Op
+    };
+
+    SkRect rectA, rectB;
+
+    rectA.iset(10, 10, 50, 50);
+    rectB.iset(40, 40, 80, 80);
+
+    SkPath clipA, clipB;
+
+    clipA.addRoundRect(rectA, SkIntToScalar(5), SkIntToScalar(5));
+    clipB.addRoundRect(rectB, SkIntToScalar(5), SkIntToScalar(5));
+
+    SkClipStack stack;
+    SkRect bound;
+
+    int testCase = 0;
+    for (int invBits = 0; invBits < 4; ++invBits) {
+        for (size_t op = 0; op < SK_ARRAY_COUNT(gOps); ++op) {
+
+            stack.save();
+            bool doInvA = SkToBool(invBits & 1);
+            bool doInvB = SkToBool(invBits & 2);
+
+            clipA.setFillType(doInvA ? SkPath::kInverseEvenOdd_FillType :
+                                       SkPath::kEvenOdd_FillType);
+            clipB.setFillType(doInvB ? SkPath::kInverseEvenOdd_FillType :
+                                       SkPath::kEvenOdd_FillType);
+
+            stack.clipDevPath(clipA, SkRegion::kIntersect_Op, false);
+            stack.clipDevPath(clipB, gOps[op], false);
+
+            stack.getConservativeBounds(0, 0, 100, 100, &bound);
+
+            SkASSERT(testCase < gNumCases);
+            SkASSERT(bound == gAnswerRectsBW[testCase]);
+            ++testCase;
+
+            stack.restore();
+        }
+    }
+}
+
 static void TestClipStack(skiatest::Reporter* reporter) {
     SkClipStack stack;
 
@@ -219,6 +300,7 @@ static void TestClipStack(skiatest::Reporter* reporter) {
 
     test_assign_and_comparison(reporter);
     test_iterators(reporter);
+    test_bounds(reporter);
 }
 
 #include "TestClassDef.h"