Port convolve functions to SkOpts

src/core/SkBitmapScaler.cpp

Index: src/core/SkBitmapScaler.cpp
diff --git a/src/core/SkBitmapScaler.cpp b/src/core/SkBitmapScaler.cpp
index 25fbd1fe78763804221c3226f36f533aa4e115a4..b4ade85a7536bf58eb49c50334973488e465943c 100644
--- a/src/core/SkBitmapScaler.cpp
+++ b/src/core/SkBitmapScaler.cpp
@@ -109,93 +109,92 @@ SkResizeFilter::SkResizeFilter(SkBitmapScaler::ResizeMethod method,
 // the coefficients can be shared. For periods of 1 we can consider
 // loading the factors only once outside the borders.
 void SkResizeFilter::computeFilters(int srcSize,
-                                  float destSubsetLo, float destSubsetSize,
-                                  float scale,
-                                  SkConvolutionFilter1D* output) {
-  float destSubsetHi = destSubsetLo + destSubsetSize;  // [lo, hi)
-
-  // When we're doing a magnification, the scale will be larger than one. This
-  // means the destination pixels are much smaller than the source pixels, and
-  // that the range covered by the filter won't necessarily cover any source
-  // pixel boundaries. Therefore, we use these clamped values (max of 1) for
-  // some computations.
-  float clampedScale = SkTMin(1.0f, scale);
-
-  // This is how many source pixels from the center we need to count
-  // to support the filtering function.
-  float srcSupport = fBitmapFilter->width() / clampedScale;
-
-  float invScale = 1.0f / scale;
-
-  SkSTArray<64, float, true> filterValuesArray;
-  SkSTArray<64, SkConvolutionFilter1D::ConvolutionFixed, true> fixedFilterValuesArray;
-
-  // Loop over all pixels in the output range. We will generate one set of
-  // filter values for each one. Those values will tell us how to blend the
-  // source pixels to compute the destination pixel.
-
-  // This is the pixel in the source directly under the pixel in the dest.
-  // Note that we base computations on the "center" of the pixels. To see
-  // why, observe that the destination pixel at coordinates (0, 0) in a 5.0x
-  // downscale should "cover" the pixels around the pixel with *its center*
-  // at coordinates (2.5, 2.5) in the source, not those around (0, 0).
-  // Hence we need to scale coordinates (0.5, 0.5), not (0, 0).
-  destSubsetLo = SkScalarFloorToScalar(destSubsetLo);
-  destSubsetHi = SkScalarCeilToScalar(destSubsetHi);
-  float srcPixel = (destSubsetLo + 0.5f) * invScale;
-  int destLimit = SkScalarTruncToInt(destSubsetHi - destSubsetLo);
-  output->reserveAdditional(destLimit, SkScalarCeilToInt(destLimit * srcSupport * 2));
-  for (int destI = 0; destI < destLimit; srcPixel += invScale, destI++)
-  {
-    // Compute the (inclusive) range of source pixels the filter covers.
-    float srcBegin = SkTMax(0.f, SkScalarFloorToScalar(srcPixel - srcSupport));
-    float srcEnd = SkTMin(srcSize - 1.f, SkScalarCeilToScalar(srcPixel + srcSupport));
-
-    // Compute the unnormalized filter value at each location of the source
-    // it covers.
-
-    // Sum of the filter values for normalizing.
-    // Distance from the center of the filter, this is the filter coordinate
-    // in source space. We also need to consider the center of the pixel
-    // when comparing distance against 'srcPixel'. In the 5x downscale
-    // example used above the distance from the center of the filter to
-    // the pixel with coordinates (2, 2) should be 0, because its center
-    // is at (2.5, 2.5).
-    float destFilterDist = (srcBegin + 0.5f - srcPixel) * clampedScale;
-    int filterCount = SkScalarTruncToInt(srcEnd - srcBegin) + 1;
-    if (filterCount <= 0) {
-        // true when srcSize is equal to srcPixel - srcSupport; this may be a bug
-        return;
-    }
-    filterValuesArray.reset(filterCount);
-    float filterSum = fBitmapFilter->evaluate_n(destFilterDist, clampedScale, filterCount,
+                                    float destSubsetLo, float destSubsetSize,
+                                    float scale,
+                                    SkConvolutionFilter1D* output) {
+    float destSubsetHi = destSubsetLo + destSubsetSize;  // [lo, hi)
+
+    // When we're doing a magnification, the scale will be larger than one. This
+    // means the destination pixels are much smaller than the source pixels, and
+    // that the range covered by the filter won't necessarily cover any source
+    // pixel boundaries. Therefore, we use these clamped values (max of 1) for
+    // some computations.
+    float clampedScale = SkTMin(1.0f, scale);
+
+    // This is how many source pixels from the center we need to count
+    // to support the filtering function.
+    float srcSupport = fBitmapFilter->width() / clampedScale;
+
+    float invScale = 1.0f / scale;
+
+    SkSTArray<64, float, true> filterValuesArray;
+    SkSTArray<64, SkConvolutionFilter1D::ConvolutionFixed, true> fixedFilterValuesArray;
+
+    // Loop over all pixels in the output range. We will generate one set of
+    // filter values for each one. Those values will tell us how to blend the
+    // source pixels to compute the destination pixel.
+
+    // This is the pixel in the source directly under the pixel in the dest.
+    // Note that we base computations on the "center" of the pixels. To see
+    // why, observe that the destination pixel at coordinates (0, 0) in a 5.0x
+    // downscale should "cover" the pixels around the pixel with *its center*
+    // at coordinates (2.5, 2.5) in the source, not those around (0, 0).
+    // Hence we need to scale coordinates (0.5, 0.5), not (0, 0).
+    destSubsetLo = SkScalarFloorToScalar(destSubsetLo);
+    destSubsetHi = SkScalarCeilToScalar(destSubsetHi);
+    float srcPixel = (destSubsetLo + 0.5f) * invScale;
+    int destLimit = SkScalarTruncToInt(destSubsetHi - destSubsetLo);
+    output->reserveAdditional(destLimit, SkScalarCeilToInt(destLimit * srcSupport * 2));
+    for (int destI = 0; destI < destLimit; srcPixel += invScale, destI++) {
+        // Compute the (inclusive) range of source pixels the filter covers.
+        float srcBegin = SkTMax(0.f, SkScalarFloorToScalar(srcPixel - srcSupport));
+        float srcEnd = SkTMin(srcSize - 1.f, SkScalarCeilToScalar(srcPixel + srcSupport));
+
+        // Compute the unnormalized filter value at each location of the source
+        // it covers.
+
+        // Sum of the filter values for normalizing.
+        // Distance from the center of the filter, this is the filter coordinate
+        // in source space. We also need to consider the center of the pixel
+        // when comparing distance against 'srcPixel'. In the 5x downscale
+        // example used above the distance from the center of the filter to
+        // the pixel with coordinates (2, 2) should be 0, because its center
+        // is at (2.5, 2.5).
+        float destFilterDist = (srcBegin + 0.5f - srcPixel) * clampedScale;
+        int filterCount = SkScalarTruncToInt(srcEnd - srcBegin) + 1;
+        if (filterCount <= 0) {
+            // true when srcSize is equal to srcPixel - srcSupport; this may be a bug
+            return;
+        }
+        filterValuesArray.reset(filterCount);
+        float filterSum = fBitmapFilter->evaluate_n(destFilterDist, clampedScale, filterCount,
                                                 filterValuesArray.begin());
 
-    // The filter must be normalized so that we don't affect the brightness of
-    // the image. Convert to normalized fixed point.
-    int fixedSum = 0;
-    fixedFilterValuesArray.reset(filterCount);
-    const float* filterValues = filterValuesArray.begin();
-    SkConvolutionFilter1D::ConvolutionFixed* fixedFilterValues = fixedFilterValuesArray.begin();
-    float invFilterSum = 1 / filterSum;
-    for (int fixedI = 0; fixedI < filterCount; fixedI++) {
-      int curFixed = SkConvolutionFilter1D::FloatToFixed(filterValues[fixedI] * invFilterSum);
-      fixedSum += curFixed;
-      fixedFilterValues[fixedI] = SkToS16(curFixed);
+        // The filter must be normalized so that we don't affect the brightness of
+        // the image. Convert to normalized fixed point.
+        int fixedSum = 0;
+        fixedFilterValuesArray.reset(filterCount);
+        const float* filterValues = filterValuesArray.begin();
+        SkConvolutionFilter1D::ConvolutionFixed* fixedFilterValues = fixedFilterValuesArray.begin();
+        float invFilterSum = 1 / filterSum;
+        for (int fixedI = 0; fixedI < filterCount; fixedI++) {
+            int curFixed = SkConvolutionFilter1D::FloatToFixed(filterValues[fixedI] * invFilterSum);
+            fixedSum += curFixed;
+            fixedFilterValues[fixedI] = SkToS16(curFixed);
+        }
+        SkASSERT(fixedSum <= 0x7FFF);
+
+        // The conversion to fixed point will leave some rounding errors, which
+        // we add back in to avoid affecting the brightness of the image. We
+        // arbitrarily add this to the center of the filter array (this won't always
+        // be the center of the filter function since it could get clipped on the
+        // edges, but it doesn't matter enough to worry about that case).
+        int leftovers = SkConvolutionFilter1D::FloatToFixed(1) - fixedSum;
+        fixedFilterValues[filterCount / 2] += leftovers;
+
+        // Now it's ready to go.
+        output->AddFilter(SkScalarFloorToInt(srcBegin), fixedFilterValues, filterCount);
     }
-    SkASSERT(fixedSum <= 0x7FFF);
-
-    // The conversion to fixed point will leave some rounding errors, which
-    // we add back in to avoid affecting the brightness of the image. We
-    // arbitrarily add this to the center of the filter array (this won't always
-    // be the center of the filter function since it could get clipped on the
-    // edges, but it doesn't matter enough to worry about that case).
-    int leftovers = SkConvolutionFilter1D::FloatToFixed(1) - fixedSum;
-    fixedFilterValues[filterCount / 2] += leftovers;
-
-    // Now it's ready to go.
-    output->AddFilter(SkScalarFloorToInt(srcBegin), fixedFilterValues, filterCount);
-  }
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
@@ -214,9 +213,6 @@ bool SkBitmapScaler::Resize(const SkPixmap& result, const SkPixmap& source, Resi
         return false;
     }
 
-    SkConvolutionProcs convolveProcs= { nullptr, nullptr, nullptr };
-    PlatformConvolutionProcs(&convolveProcs);
-
     SkRect destSubset = SkRect::MakeIWH(result.width(), result.height());
 
     SkResizeFilter filter(method, source.width(), source.height(),
@@ -230,8 +226,7 @@ bool SkBitmapScaler::Resize(const SkPixmap& result, const SkPixmap& source, Resi
     return BGRAConvolve2D(sourceSubset, static_cast<int>(source.rowBytes()),
                           !source.isOpaque(), filter.xFilter(), filter.yFilter(),
                           static_cast<int>(result.rowBytes()),
-                          static_cast<unsigned char*>(result.writable_addr()),
-                          convolveProcs, true);
+                          static_cast<unsigned char*>(result.writable_addr()));
 }
 
 bool SkBitmapScaler::Resize(SkBitmap* resultPtr, const SkPixmap& source, ResizeMethod method,