quick hackup of SkNx SkMatrixConvolutionImageFilter

src/effects/SkMatrixConvolutionImageFilter.cpp

Index: src/effects/SkMatrixConvolutionImageFilter.cpp
diff --git a/src/effects/SkMatrixConvolutionImageFilter.cpp b/src/effects/SkMatrixConvolutionImageFilter.cpp
index f5d9a3f7d220e2fd01b6a964334be0799c4b7720..870ef159581160d5b928d9709935740cfc0a6bdd 100644
--- a/src/effects/SkMatrixConvolutionImageFilter.cpp
+++ b/src/effects/SkMatrixConvolutionImageFilter.cpp
@@ -8,6 +8,7 @@
 #include "SkMatrixConvolutionImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
+#include "SkNx.h"
 #include "SkReadBuffer.h"
 #include "SkSpecialImage.h"
 #include "SkSpecialSurface.h"
@@ -174,7 +175,7 @@ void SkMatrixConvolutionImageFilter::filterPixels(const SkBitmap& src,
     for (int y = rect.fTop; y < rect.fBottom; ++y) {
         SkPMColor* dptr = result->getAddr32(rect.fLeft - bounds.fLeft, y - bounds.fTop);
         for (int x = rect.fLeft; x < rect.fRight; ++x) {
-            SkScalar sumA = 0, sumR = 0, sumG = 0, sumB = 0;
+            Sk4s sum = 0;
             for (int cy = 0; cy < fKernelSize.fHeight; cy++) {
                 for (int cx = 0; cx < fKernelSize.fWidth; cx++) {
                     SkPMColor s = PixelFetcher::fetch(src,
@@ -182,26 +183,19 @@ void SkMatrixConvolutionImageFilter::filterPixels(const SkBitmap& src,
                                                       y + cy - fKernelOffset.fY,
                                                       bounds);
                     SkScalar k = fKernel[cy * fKernelSize.fWidth + cx];
-                    if (convolveAlpha) {
-                        sumA += SkScalarMul(SkIntToScalar(SkGetPackedA32(s)), k);
-                    }
-                    sumR += SkScalarMul(SkIntToScalar(SkGetPackedR32(s)), k);
-                    sumG += SkScalarMul(SkIntToScalar(SkGetPackedG32(s)), k);
-                    sumB += SkScalarMul(SkIntToScalar(SkGetPackedB32(s)), k);
+
+                    sum += k * SkNx_cast<SkScalar>(Sk4b::Load(&s));
                 }
             }
-            int a = convolveAlpha
-                  ? SkClampMax(SkScalarFloorToInt(SkScalarMul(sumA, fGain) + fBias), 255)
-                  : 255;
-            int r = SkClampMax(SkScalarFloorToInt(SkScalarMul(sumR, fGain) + fBias), a);
-            int g = SkClampMax(SkScalarFloorToInt(SkScalarMul(sumG, fGain) + fBias), a);
-            int b = SkClampMax(SkScalarFloorToInt(SkScalarMul(sumB, fGain) + fBias), a);
-            if (!convolveAlpha) {
-                a = SkGetPackedA32(PixelFetcher::fetch(src, x, y, bounds));
-                *dptr++ = SkPreMultiplyARGB(a, r, g, b);
+            Sk4s d = Sk4s::Max(0, Sk4s::Min(sum * fGain + fBias, 255.0f));
+
+            if (convolveAlpha) {
+                d = Sk4s::Min(d, d[3]);
             } else {
-                *dptr++ = SkPackARGB32(a, r, g, b);
+                SkScalar a01 = (1/255.0f) * SkGetPackedA32(PixelFetcher::fetch(src, x, y, bounds));
+                d = Sk4s{d[0],d[1],d[2], 255} * a01;
             }
+            SkNx_cast<uint8_t>(d).store(dptr++);
         }
     }
 }