Make the value for shadowRadius less than 1.0 work

bug:22806069

Shadow effect is not visible if the shadowRadius is set
between 0.1 and 1.0.

Cherry-pick of 8d9b5fbd from AOSP

Change-Id: Ifff71f44d66ba604bd751bb1df96a9904ae7998e

3 files changed, 11 insertions, 9 deletions

diff --git a/libs/hwui/FontRenderer.cpp b/libs/hwui/FontRenderer.cpp
index 9be8c7d45bca..057c231012a4 100644
--- a/libs/hwui/FontRenderer.cpp
+++ b/libs/hwui/FontRenderer.cpp
@@ -732,7 +732,7 @@ void FontRenderer::blurImage(uint8_t** image, int32_t width, int32_t height, flo
 #endif
 
     std::unique_ptr<float[]> gaussian(new float[2 * intRadius + 1]);
-    Blur::generateGaussianWeights(gaussian.get(), intRadius);
+    Blur::generateGaussianWeights(gaussian.get(), radius);
 
     std::unique_ptr<uint8_t[]> scratch(new uint8_t[width * height]);
     Blur::horizontal(gaussian.get(), intRadius, *image, scratch.get(), width, height);
diff --git a/libs/hwui/utils/Blur.cpp b/libs/hwui/utils/Blur.cpp
index 6884aedc2bff..9b70765ee8ad 100644
--- a/libs/hwui/utils/Blur.cpp
+++ b/libs/hwui/utils/Blur.cpp
@@ -58,7 +58,9 @@ static float legacyConvertRadiusToSigma(float radius) {
     return radius > 0 ? 0.3f * radius + 0.6f : 0.0f;
 }
 
-void Blur::generateGaussianWeights(float* weights, int32_t radius) {
+void Blur::generateGaussianWeights(float* weights, float radius) {
+    int32_t intRadius = convertRadiusToInt(radius);
+
     // Compute gaussian weights for the blur
     // e is the euler's number
     static float e = 2.718281828459045f;
@@ -66,7 +68,7 @@ void Blur::generateGaussianWeights(float* weights, int32_t radius) {
     // g(x) = ( 1 / sqrt( 2 * pi ) * sigma) * e ^ ( -x^2 / 2 * sigma^2 )
     // x is of the form [-radius .. 0 .. radius]
     // and sigma varies with radius.
-    float sigma = legacyConvertRadiusToSigma((float) radius);
+    float sigma = legacyConvertRadiusToSigma(radius);
 
     // Now compute the coefficints
     // We will store some redundant values to save some math during
@@ -76,16 +78,16 @@ void Blur::generateGaussianWeights(float* weights, int32_t radius) {
     float coeff2 = - 1.0f / (2.0f * sigma * sigma);
 
     float normalizeFactor = 0.0f;
-    for (int32_t r = -radius; r <= radius; r ++) {
+    for (int32_t r = -intRadius; r <= intRadius; r ++) {
         float floatR = (float) r;
-        weights[r + radius] = coeff1 * pow(e, floatR * floatR * coeff2);
-        normalizeFactor += weights[r + radius];
+        weights[r + intRadius] = coeff1 * pow(e, floatR * floatR * coeff2);
+        normalizeFactor += weights[r + intRadius];
     }
 
     //Now we need to normalize the weights because all our coefficients need to add up to one
     normalizeFactor = 1.0f / normalizeFactor;
-    for (int32_t r = -radius; r <= radius; r ++) {
-        weights[r + radius] *= normalizeFactor;
+    for (int32_t r = -intRadius; r <= intRadius; r ++) {
+        weights[r + intRadius] *= normalizeFactor;
     }
 }
 
diff --git a/libs/hwui/utils/Blur.h b/libs/hwui/utils/Blur.h
index b14533312719..3f21832bf2b5 100644
--- a/libs/hwui/utils/Blur.h
+++ b/libs/hwui/utils/Blur.h
@@ -34,7 +34,7 @@ public:
     // accounts for that error and snaps to the appropriate integer boundary.
     static uint32_t convertRadiusToInt(float radius);
 
-    static void generateGaussianWeights(float* weights, int32_t radius);
+    static void generateGaussianWeights(float* weights, float radius);
     static void horizontal(float* weights, int32_t radius, const uint8_t* source,
         uint8_t* dest, int32_t width, int32_t height);
     static void vertical(float* weights, int32_t radius, const uint8_t* source,