Fix srcBounds computation in SkMatrixConvolutionImageFilter

Note that this does change the behavior of the cropRect for the repeated case. The cropRect now only acts as a hard clip on the output.

BUG= skia:7766

Change-Id: I1d66678bc797cd4835701cd20c36e68b22ac880a
Reviewed-on: https://skia-review.googlesource.com/127338
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

10 files changed, 50 insertions, 15 deletions

diff --git a/include/core/SkColorFilter.h b/include/core/SkColorFilter.h
index 97c8220c6b..e8b09bae9c 100644
--- a/include/core/SkColorFilter.h
+++ b/include/core/SkColorFilter.h
@@ -135,7 +135,7 @@ public:
 #endif
 
     bool affectsTransparentBlack() const {
-        return this->filterColor(0) != 0;
+        return this->filterColor(SK_ColorTRANSPARENT) != SK_ColorTRANSPARENT;
     }
 
     virtual void toString(SkString* str) const = 0;
diff --git a/include/core/SkImageFilter.h b/include/core/SkImageFilter.h
index 2528009e24..70f5513843 100644
--- a/include/core/SkImageFilter.h
+++ b/include/core/SkImageFilter.h
@@ -155,8 +155,13 @@ public:
      * be exact, but should never be smaller than the real answer. The default
      * implementation recursively unions all input bounds, or returns the
      * source rect if no inputs.
+     *
+     * In kReverse mode, 'inputRect' is the device-space bounds of the input pixels. In kForward
+     * mode it should always be null. If 'inputRect' is null in kReverse mode the resulting
+     * answer may be incorrect.
      */
-    SkIRect filterBounds(const SkIRect& src, const SkMatrix& ctm, MapDirection) const;
+    SkIRect filterBounds(const SkIRect& src, const SkMatrix& ctm,
+                         MapDirection, const SkIRect* inputRect = nullptr) const;
 
 #if SK_SUPPORT_GPU
     static sk_sp<SkSpecialImage> DrawWithFP(GrContext* context,
@@ -320,12 +325,16 @@ protected:
      * and returns the union of those results. If a derived class has special
      * recursion requirements (e.g., it has an input which does not participate
      * in bounds computation), it can be overridden here.
+     * In kReverse mode, 'inputRect' is the device-space bounds of the input pixels. In kForward
+     * mode it should always be null. If 'inputRect' is null in kReverse mode the resulting
+     * answer may be incorrect.
      *
      * Note that this function is *not* responsible for mapping the rect for
      * this node's filter bounds requirements (i.e., calling
      * onFilterNodeBounds()); that is handled by filterBounds().
      */
-    virtual SkIRect onFilterBounds(const SkIRect&, const SkMatrix&, MapDirection) const;
+    virtual SkIRect onFilterBounds(const SkIRect&, const SkMatrix& ctm,
+                                   MapDirection, const SkIRect* inputRect) const;
 
     /**
      * Performs a forwards or reverse mapping of the given rect to accommodate
@@ -339,8 +348,12 @@ protected:
      * inverse of the other. For example, blurring expands the given rect
      * in both forward and reverse directions. Unlike
      * onFilterBounds(), this function is non-recursive.
+     * In kReverse mode, 'inputRect' will be the device space bounds of the input pixels. In
+     * kForward mode, 'inputRect' should always be null. If 'inputRect' is null in kReverse mode
+     * the resulting answer may be incorrect.
      */
-    virtual SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix&, MapDirection) const;
+    virtual SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix& ctm,
+                                       MapDirection, const SkIRect* inputRect) const;
 
     // Helper function which invokes filter processing on the input at the
     // specified "index". If the input is null, it returns "src" and leaves
@@ -416,6 +429,15 @@ protected:
         return sk_ref_sp(const_cast<SkImageFilter*>(this));
     }
 
+    // If 'srcBounds' will sample outside the border of 'originalSrcBounds' (i.e., the sample
+    // will wrap around to the other side) we must preserve the far side of the src along that
+    // axis (e.g., if we will sample beyond the left edge of the src, the right side must be
+    // preserved for the repeat sampling to work).
+    static SkIRect DetermineRepeatedSrcBound(const SkIRect& srcBounds,
+                                             const SkIVector& filterOffset,
+                                             const SkISize& filterSize,
+                                             const SkIRect& originalSrcBounds);
+
 private:
     // For makeColorSpace().
     friend class SkColorSpaceXformer;
diff --git a/include/effects/SkComposeImageFilter.h b/include/effects/SkComposeImageFilter.h
index dd44df5d9c..0bfb7d8c5c 100644
--- a/include/effects/SkComposeImageFilter.h
+++ b/include/effects/SkComposeImageFilter.h
@@ -27,7 +27,8 @@ protected:
     sk_sp<SkSpecialImage> onFilterImage(SkSpecialImage* source, const Context&,
                                         SkIPoint* offset) const override;
     sk_sp<SkImageFilter> onMakeColorSpace(SkColorSpaceXformer*) const override;
-    SkIRect onFilterBounds(const SkIRect&, const SkMatrix&, MapDirection) const override;
+    SkIRect onFilterBounds(const SkIRect&, const SkMatrix& ctm,
+                           MapDirection, const SkIRect* inputRect) const override;
     bool onCanHandleComplexCTM() const override { return true; }
 
 private:
diff --git a/include/effects/SkDisplacementMapEffect.h b/include/effects/SkDisplacementMapEffect.h
index af4d6fd10e..daf03d742c 100644
--- a/include/effects/SkDisplacementMapEffect.h
+++ b/include/effects/SkDisplacementMapEffect.h
@@ -35,10 +35,11 @@ public:
 
     SkRect computeFastBounds(const SkRect& src) const override;
 
-    virtual SkIRect onFilterBounds(const SkIRect& src, const SkMatrix&,
-                                   MapDirection) const override;
+    virtual SkIRect onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
+                                   MapDirection, const SkIRect* inputRect) const override;
     sk_sp<SkImageFilter> onMakeColorSpace(SkColorSpaceXformer*) const override;
-    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix&, MapDirection) const override;
+    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix& ctm,
+                               MapDirection, const SkIRect* inputRect) const override;
 
     void toString(SkString* str) const override;
 
diff --git a/include/effects/SkDropShadowImageFilter.h b/include/effects/SkDropShadowImageFilter.h
index f6b27db271..d1ee44c168 100644
--- a/include/effects/SkDropShadowImageFilter.h
+++ b/include/effects/SkDropShadowImageFilter.h
@@ -37,7 +37,8 @@ protected:
     sk_sp<SkSpecialImage> onFilterImage(SkSpecialImage* source, const Context&,
                                         SkIPoint* offset) const override;
     sk_sp<SkImageFilter> onMakeColorSpace(SkColorSpaceXformer*) const override;
-    SkIRect onFilterNodeBounds(const SkIRect& src, const SkMatrix&, MapDirection) const override;
+    SkIRect onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
+                               MapDirection, const SkIRect* inputRect) const override;
 
 private:
     SkDropShadowImageFilter(SkScalar dx, SkScalar dy, SkScalar sigmaX, SkScalar sigmaY, SkColor,
diff --git a/include/effects/SkImageSource.h b/include/effects/SkImageSource.h
index 25b169c20d..6ef855ab93 100644
--- a/include/effects/SkImageSource.h
+++ b/include/effects/SkImageSource.h
@@ -31,7 +31,8 @@ protected:
                                         SkIPoint* offset) const override;
     sk_sp<SkImageFilter> onMakeColorSpace(SkColorSpaceXformer*) const override;
 
-    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix&, MapDirection) const override;
+    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix& ctm,
+                               MapDirection, const SkIRect* inputRect) const override;
 
 private:
     explicit SkImageSource(sk_sp<SkImage>);
diff --git a/include/effects/SkMatrixConvolutionImageFilter.h b/include/effects/SkMatrixConvolutionImageFilter.h
index 94ea716842..5361fef928 100644
--- a/include/effects/SkMatrixConvolutionImageFilter.h
+++ b/include/effects/SkMatrixConvolutionImageFilter.h
@@ -85,7 +85,8 @@ protected:
     sk_sp<SkSpecialImage> onFilterImage(SkSpecialImage* source, const Context&,
                                         SkIPoint* offset) const override;
     sk_sp<SkImageFilter> onMakeColorSpace(SkColorSpaceXformer*) const override;
-    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix&, MapDirection) const override;
+    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix& ctm,
+                               MapDirection, const SkIRect* inputRect) const override;
     bool affectsTransparentBlack() const override;
 
 private:
@@ -100,19 +101,23 @@ private:
     template <class PixelFetcher, bool convolveAlpha>
     void filterPixels(const SkBitmap& src,
                       SkBitmap* result,
+                      SkIVector& offset,
                       const SkIRect& rect,
                       const SkIRect& bounds) const;
     template <class PixelFetcher>
     void filterPixels(const SkBitmap& src,
                       SkBitmap* result,
+                      SkIVector& offset,
                       const SkIRect& rect,
                       const SkIRect& bounds) const;
     void filterInteriorPixels(const SkBitmap& src,
                               SkBitmap* result,
+                              SkIVector& offset,
                               const SkIRect& rect,
                               const SkIRect& bounds) const;
     void filterBorderPixels(const SkBitmap& src,
                             SkBitmap* result,
+                            SkIVector& offset,
                             const SkIRect& rect,
                             const SkIRect& bounds) const;
 
diff --git a/include/effects/SkMorphologyImageFilter.h b/include/effects/SkMorphologyImageFilter.h
index b75fe26d8a..d88a31dc65 100644
--- a/include/effects/SkMorphologyImageFilter.h
+++ b/include/effects/SkMorphologyImageFilter.h
@@ -16,7 +16,8 @@
 class SK_API SkMorphologyImageFilter : public SkImageFilter {
 public:
     SkRect computeFastBounds(const SkRect& src) const override;
-    SkIRect onFilterNodeBounds(const SkIRect& src, const SkMatrix&, MapDirection) const override;
+    SkIRect onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
+                               MapDirection, const SkIRect* inputRect) const override;
 
     /**
      * All morphology procs have the same signature: src is the source buffer, dst the
diff --git a/include/effects/SkOffsetImageFilter.h b/include/effects/SkOffsetImageFilter.h
index 9356c70fd2..2d7b14f652 100644
--- a/include/effects/SkOffsetImageFilter.h
+++ b/include/effects/SkOffsetImageFilter.h
@@ -27,7 +27,8 @@ protected:
     sk_sp<SkSpecialImage> onFilterImage(SkSpecialImage* source, const Context&,
                                         SkIPoint* offset) const override;
     sk_sp<SkImageFilter> onMakeColorSpace(SkColorSpaceXformer*) const override;
-    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix&, MapDirection) const override;
+    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix& ctm,
+                               MapDirection, const SkIRect* inputRect) const override;
 
 private:
     SkOffsetImageFilter(SkScalar dx, SkScalar dy, sk_sp<SkImageFilter> input, const CropRect*);
diff --git a/include/effects/SkTileImageFilter.h b/include/effects/SkTileImageFilter.h
index f37982bbb9..f62d8a02d4 100644
--- a/include/effects/SkTileImageFilter.h
+++ b/include/effects/SkTileImageFilter.h
@@ -21,8 +21,10 @@ public:
                                      const SkRect& dst,
                                      sk_sp<SkImageFilter> input);
 
-    SkIRect onFilterBounds(const SkIRect& src, const SkMatrix&, MapDirection) const override;
-    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix&, MapDirection) const override;
+    SkIRect onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
+                           MapDirection, const SkIRect* inputRect) const override;
+    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix& ctm,
+                               MapDirection, const SkIRect* inputRect) const override;
     SkRect computeFastBounds(const SkRect& src) const override;
 
     void toString(SkString* str) const override;