Clean up mask blur code.

This code has interpolation for small radii like the old code.
This code is protected by the flag:

SK_LEGACY_SUPPORT_INTEGER_SMALL_RADII

In addition, I have improved the scale calculation for Gauss to be more
accurate, and it is also protected by the flag:

SK_LEGACY_SUPPORT_INTEGER_SMALL_RADII

When SK_LEGACY_SUPPORT_INTEGER_SMALL_RADII is defined, then there
is no difference.


Bug: skia:
Change-Id: I588299c3768dd009852ce41f33a6a8572d9f4ad3
Reviewed-on: https://skia-review.googlesource.com/41746
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>

1 files changed, 2 insertions, 57 deletions

diff --git a/src/core/SkMaskBlurFilter.h b/src/core/SkMaskBlurFilter.h
index 26efe95de5..0a7895d95c 100644
--- a/src/core/SkMaskBlurFilter.h
+++ b/src/core/SkMaskBlurFilter.h
@@ -19,39 +19,6 @@
 // https://drafts.fxtf.org/filters/#feGaussianBlurElement
 class SkMaskBlurFilter {
 public:
-    // Given a filter specified by sigma, generate various quantities.
-    class FilterInfo {
-    public:
-        explicit FilterInfo(double sigma);
-
-        // The final weight to divide by given a box size calculated from sigma accumulated for
-        // all three passes. For example, if the box size is 5, then the final weight for all
-        // three passes is 5^3 or 125.
-        uint64_t weight() const;
-
-        // The distance between the first value of the dst and the first value of the src.
-        uint32_t borderSize() const;
-
-        // The size of the box filter.
-        size_t   diameter(uint8_t) const;
-
-        // A factor used to simulate division using multiplication and shift.
-        uint64_t scaledWeight() const;
-
-        // Returned when sigma < 2.
-        bool isSmall() const;
-
-        // Factors for interpolating box blur.
-        std::tuple<uint64_t, uint64_t> interpFactors() const;
-
-    private:
-        const bool                           fIsSmall;
-        const uint32_t                       fFilterWindow;
-        const uint64_t                       fWeight;
-        const uint64_t                       fScaledWeight;
-        const std::tuple<uint64_t, uint64_t> fInterpFactors;
-    };
-
     // Create an object suitable for filtering an SkMask using a filter with width sigmaW and
     // height sigmaH.
     SkMaskBlurFilter(double sigmaW, double sigmaH);
@@ -63,30 +30,8 @@ public:
     SkIPoint blur(const SkMask& src, SkMask* dst) const;
 
 private:
-    size_t bufferSize(uint8_t bufferPass) const;
-
-    void blurOneScan(const FilterInfo& gen, size_t width,
-                     const uint8_t* src, size_t srcStride, const uint8_t* srcEnd,
-                           uint8_t* dst, size_t dstStride,       uint8_t* dstEnd) const;
-
-    void blurOneScanBox(const FilterInfo& gen,
-                        const uint8_t* src, size_t srcStride, const uint8_t* srcEnd,
-                              uint8_t* dst, size_t dstStride,       uint8_t* dstEnd) const;
-
-    void blurOneScanBoxInterp(const FilterInfo& gen, size_t width,
-                              const uint8_t* src, size_t srcStride, const uint8_t* srcEnd,
-                                    uint8_t* dst, size_t dstStride,       uint8_t* dstEnd) const;
-
-    void blurOneScanGauss(const FilterInfo& gen,
-                          const uint8_t* src, size_t srcStride, const uint8_t* srcEnd,
-                                uint8_t* dst, size_t dstStride,       uint8_t* dstEnd) const;
-
-
-    const FilterInfo            fInfoW,
-                                fInfoH;
-    std::unique_ptr<uint32_t[]> fBuffer0,
-                                fBuffer1,
-                                fBuffer2;
+    const double fSigmaW;
+    const double fSigmaH;
 };
 
 #endif  // SkBlurMaskFilter_DEFINED