Experimental blur code.

This uses a new method of blurring that runs the three 
passes of the box filter in a single pass. This implementation
currently only does 1x1 pixel at a time, but it should be simple
to expand to 4x4 pixels at a time.

On the  blur_10_normal_high_quality benchmark, the new is 7% faster
than the old code. For the blur_100.50_normal_high_quality
benchmark, the new code is 11% slower.

Change-Id: Iea37294abc7c27de5ad569adf8bc62df77eafd02
Reviewed-on: https://skia-review.googlesource.com/21739
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Mike Reed <reed@google.com>

1 files changed, 58 insertions, 38 deletions

diff --git a/src/effects/SkBlurMask.cpp b/src/effects/SkBlurMask.cpp
index eee16313f6..fe59ab8269 100644
--- a/src/effects/SkBlurMask.cpp
+++ b/src/effects/SkBlurMask.cpp
@@ -7,6 +7,7 @@
 
 
 #include "SkBlurMask.h"
+#include "SkMaskBlurFilter.h"
 #include "SkMath.h"
 #include "SkTemplates.h"
 #include "SkEndian.h"
@@ -406,13 +407,7 @@ static int boxBlurInterp(const uint8_t* src, int src_y_stride, uint8_t* dst,
     return new_width;
 }
 
-static void get_adjusted_radii(SkScalar passRadius, int *loRadius, int *hiRadius)
-{
-    *loRadius = *hiRadius = SkScalarCeilToInt(passRadius);
-    if (SkIntToScalar(*hiRadius) - passRadius > 0.5f) {
-        *loRadius = *hiRadius - 1;
-    }
-}
+
 
 #include "SkColorPriv.h"
 
@@ -487,6 +482,17 @@ bool SkBlurMask::BoxBlur(SkMask* dst, const SkMask& src,
         return false;
     }
 
+    SkIPoint border;
+
+#ifdef SK_SUPPORT_LEGACY_MASK_BLUR
+
+    auto get_adjusted_radii = [](SkScalar passRadius, int *loRadius, int *hiRadius) {
+        *loRadius = *hiRadius = SkScalarCeilToInt(passRadius);
+        if (SkIntToScalar(*hiRadius) - passRadius > 0.5f) {
+            *loRadius = *hiRadius - 1;
+        }
+    };
+
     // Force high quality off for small radii (performance)
     if (!force_quality && sigma <= SkIntToScalar(2)) {
         quality = kLow_SkBlurQuality;
@@ -496,12 +502,12 @@ bool SkBlurMask::BoxBlur(SkMask* dst, const SkMask& src,
     if (kHigh_SkBlurQuality == quality) {
         // For the high quality path the 3 pass box blur kernel width is
         // 6*rad+1 while the full Gaussian width is 6*sigma.
-        passRadius = sigma - (1/6.0f);
+        passRadius = sigma - (1 / 6.0f);
     } else {
         // For the low quality path we only attempt to cover 3*sigma of the
         // Gaussian blur area (1.5*sigma on each side). The single pass box
         // blur's kernel size is 2*rad+1.
-        passRadius = 1.5f*sigma - 0.5f;
+        passRadius = 1.5f * sigma - 0.5f;
     }
 
     // highQuality: use three box blur passes as a cheap way
@@ -522,9 +528,8 @@ bool SkBlurMask::BoxBlur(SkMask* dst, const SkMask& src,
     int padx = passCount * rx;
     int pady = passCount * ry;
 
-    if (margin) {
-        margin->set(padx, pady);
-    }
+    border = {padx, pady};
+
     dst->fBounds.set(src.fBounds.fLeft - padx, src.fBounds.fTop - pady,
                      src.fBounds.fRight + padx, src.fBounds.fBottom + pady);
 
@@ -538,15 +543,15 @@ bool SkBlurMask::BoxBlur(SkMask* dst, const SkMask& src,
             return false;   // too big to allocate, abort
         }
 
-        int             sw = src.fBounds.width();
-        int             sh = src.fBounds.height();
-        const uint8_t*  sp = src.fImage;
-        uint8_t*        dp = SkMask::AllocImage(dstSize);
+        int sw = src.fBounds.width();
+        int sh = src.fBounds.height();
+        const uint8_t* sp = src.fImage;
+        uint8_t* dp = SkMask::AllocImage(dstSize);
         SkAutoTCallVProc<uint8_t, SkMask_FreeImage> autoCall(dp);
 
         // build the blurry destination
-        SkAutoTMalloc<uint8_t>  tmpBuffer(dstSize);
-        uint8_t*                tp = tmpBuffer.get();
+        SkAutoTMalloc<uint8_t> tmpBuffer(dstSize);
+        uint8_t* tp = tmpBuffer.get();
         int w = sw, h = sh;
 
         if (outerWeight == 255) {
@@ -555,33 +560,40 @@ bool SkBlurMask::BoxBlur(SkMask* dst, const SkMask& src,
             if (kHigh_SkBlurQuality == quality) {
                 // Do three X blurs, with a transpose on the final one.
                 w = boxBlur<false>(sp, src.fRowBytes, tp, loRadius, hiRadius, w, h);
-                w = boxBlur<false>(tp, w,             dp, hiRadius, loRadius, w, h);
-                w = boxBlur<true>(dp, w,             tp, hiRadius, hiRadius, w, h);
+                w = boxBlur<false>(tp, w, dp, hiRadius, loRadius, w, h);
+                w = boxBlur<true>(dp, w, tp, hiRadius, hiRadius, w, h);
                 // Do three Y blurs, with a transpose on the final one.
-                h = boxBlur<false>(tp, h,             dp, loRadius, hiRadius, h, w);
-                h = boxBlur<false>(dp, h,             tp, hiRadius, loRadius, h, w);
-                h = boxBlur<true>(tp, h,             dp, hiRadius, hiRadius, h, w);
+                h = boxBlur<false>(tp, h, dp, loRadius, hiRadius, h, w);
+                h = boxBlur<false>(dp, h, tp, hiRadius, loRadius, h, w);
+                h = boxBlur<true>(tp, h, dp, hiRadius, hiRadius, h, w);
             } else {
                 w = boxBlur<true>(sp, src.fRowBytes, tp, rx, rx, w, h);
-                h = boxBlur<true>(tp, h,             dp, ry, ry, h, w);
+                h = boxBlur<true>(tp, h, dp, ry, ry, h, w);
             }
         } else {
             if (kHigh_SkBlurQuality == quality) {
                 // Do three X blurs, with a transpose on the final one.
                 w = boxBlurInterp<false>(sp, src.fRowBytes, tp, rx, w, h, outerWeight);
-                w = boxBlurInterp<false>(tp, w,             dp, rx, w, h, outerWeight);
-                w = boxBlurInterp<true>(dp, w,             tp, rx, w, h, outerWeight);
+                w = boxBlurInterp<false>(tp, w, dp, rx, w, h, outerWeight);
+                w = boxBlurInterp<true>(dp, w, tp, rx, w, h, outerWeight);
                 // Do three Y blurs, with a transpose on the final one.
-                h = boxBlurInterp<false>(tp, h,             dp, ry, h, w, outerWeight);
-                h = boxBlurInterp<false>(dp, h,             tp, ry, h, w, outerWeight);
-                h = boxBlurInterp<true>(tp, h,             dp, ry, h, w, outerWeight);
+                h = boxBlurInterp<false>(tp, h, dp, ry, h, w, outerWeight);
+                h = boxBlurInterp<false>(dp, h, tp, ry, h, w, outerWeight);
+                h = boxBlurInterp<true>(tp, h, dp, ry, h, w, outerWeight);
             } else {
                 w = boxBlurInterp<true>(sp, src.fRowBytes, tp, rx, w, h, outerWeight);
-                h = boxBlurInterp<true>(tp, h,             dp, ry, h, w, outerWeight);
+                h = boxBlurInterp<true>(tp, h, dp, ry, h, w, outerWeight);
             }
         }
 
-        dst->fImage = dp;
+        dst->fImage = autoCall.release();
+    }
+#else
+    SkMaskBlurFilter blurFilter{sigma, sigma};
+    border = blurFilter.blur(src, dst);
+#endif  // SK_SUPPORT_LEGACY_MASK_BLUR
+
+    if (src.fImage != nullptr) {
         // if need be, alloc the "real" dst (same size as src) and copy/merge
         // the blur into it (applying the src)
         if (style == kInner_SkBlurStyle) {
@@ -590,17 +602,21 @@ bool SkBlurMask::BoxBlur(SkMask* dst, const SkMask& src,
             if (0 == srcSize) {
                 return false;   // too big to allocate, abort
             }
+            auto blur = dst->fImage;
             dst->fImage = SkMask::AllocImage(srcSize);
+            auto blurStart = &blur[border.x() + border.y() * dst->fRowBytes];
             merge_src_with_blur(dst->fImage, src.fRowBytes,
-                                sp, src.fRowBytes,
-                                dp + passCount * (rx + ry * dst->fRowBytes),
-                                dst->fRowBytes, sw, sh);
-            SkMask::FreeImage(dp);
+                                src.fImage, src.fRowBytes,
+                                blurStart,
+                                dst->fRowBytes,
+                                src.fBounds.width(), src.fBounds.height());
+            SkMask::FreeImage(blur);
         } else if (style != kNormal_SkBlurStyle) {
-            clamp_with_orig(dp + passCount * (rx + ry * dst->fRowBytes),
-                            dst->fRowBytes, sp, src.fRowBytes, sw, sh, style);
+            auto dstStart = &dst->fImage[border.x() + border.y() * dst->fRowBytes];
+            clamp_with_orig(dstStart,
+                            dst->fRowBytes, src.fImage, src.fRowBytes,
+                            src.fBounds.width(), src.fBounds.height(), style);
         }
-        (void)autoCall.release();
     }
 
     if (style == kInner_SkBlurStyle) {
@@ -608,6 +624,10 @@ bool SkBlurMask::BoxBlur(SkMask* dst, const SkMask& src,
         dst->fRowBytes = src.fRowBytes;
     }
 
+    if (margin != nullptr) {
+        *margin = border;
+    }
+
     return true;
 }