add asAShadowBlur for android to drawlooper

src/effects/SkBlurMask.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkBlurMask.h"
 #include "SkMath.h"
 #include "SkTemplates.h"
 #include "SkEndian.h"
 
 
+// This constant approximates the scaling done in the software path's
+// "high quality" mode, in SkBlurMask::Blur() (1 / sqrt(3)).
+// IMHO, it actually should be 1:  we blur "less" than we should do
+// according to the CSS and canvas specs, simply because Safari does the same.
+// Firefox used to do the same too, until 4.0 where they fixed it.  So at some
+// point we should probably get rid of these scaling constants and rebaseline
+// all the blur tests.
+static const SkScalar kBLUR_SIGMA_SCALE = 0.57735f;
+
 SkScalar SkBlurMask::ConvertRadiusToSigma(SkScalar radius) {
-    // This constant approximates the scaling done in the software path's
-    // "high quality" mode, in SkBlurMask::Blur() (1 / sqrt(3)).
-    // IMHO, it actually should be 1:  we blur "less" than we should do
-    // according to the CSS and canvas specs, simply because Safari does the same.
-    // Firefox used to do the same too, until 4.0 where they fixed it.  So at some
-    // point we should probably get rid of these scaling constants and rebaseline
-    // all the blur tests.
-    static const SkScalar kBLUR_SIGMA_SCALE = 0.57735f;
+    return radius > 0 ? kBLUR_SIGMA_SCALE * radius + 0.5f : 0.0f;
+}
 
-    return radius ? kBLUR_SIGMA_SCALE * radius + 0.5f : 0.0f;
+SkScalar SkBlurMask::ConvertSigmaToRadius(SkScalar sigma) {
+    return sigma > 0.5f ? (sigma - 0.5f) / kBLUR_SIGMA_SCALE : 0.0f;
 }
 
 #define UNROLL_SEPARABLE_LOOPS
 
 /**
  * This function performs a box blur in X, of the given radius.  If the
  * "transpose" parameter is true, it will transpose the pixels on write,
  * such that X and Y are swapped. Reads are always performed from contiguous
  * memory in X, for speed. The destination buffer (dst) must be at least
  * (width + leftRadius + rightRadius) * height bytes in size.
@@ skipping 946 matching lines @@
         (void)autoCall.detach();
     }
 
     if (style == kInner_SkBlurStyle) {
         dst->fBounds = src.fBounds; // restore trimmed bounds
         dst->fRowBytes = src.fRowBytes;
     }
 
     return true;
 }