Added support for edge treatment parameters for BlurShader

Added configurable parameters for edge treatment for
BlurShader to determine how edge pixels are to be
computed as part of the blur kernel. This provides
the option to sample the edge pixels of the source
for larger windows as well as using transparent
(default behavior)

Fixes: 167714368
Test: Added CTS tests to verify results of edge treatment parameters
Change-Id: I3880ff4aa2e2a4eba831a0aa6d2ec77b07e84813

7 files changed, 45 insertions, 9 deletions

diff --git a/api/current.txt b/api/current.txt
index 4590325cb771..0e9b34abfb90 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -14292,6 +14292,7 @@ package android.graphics {
 
   public final class BlurShader extends android.graphics.Shader {
     ctor public BlurShader(float, float, @Nullable android.graphics.Shader);
+    ctor public BlurShader(float, float, @Nullable android.graphics.Shader, @NonNull android.graphics.Shader.TileMode);
   }
 
   public class Camera {
@@ -15630,6 +15631,7 @@ package android.graphics {
 
   public enum Shader.TileMode {
     enum_constant public static final android.graphics.Shader.TileMode CLAMP;
+    enum_constant public static final android.graphics.Shader.TileMode DECAL;
     enum_constant public static final android.graphics.Shader.TileMode MIRROR;
     enum_constant public static final android.graphics.Shader.TileMode REPEAT;
   }
diff --git a/graphics/java/android/graphics/BlurShader.java b/graphics/java/android/graphics/BlurShader.java
index 779a89051060..3bc811983336 100644
--- a/graphics/java/android/graphics/BlurShader.java
+++ b/graphics/java/android/graphics/BlurShader.java
@@ -16,6 +16,7 @@
 
 package android.graphics;
 
+import android.annotation.NonNull;
 import android.annotation.Nullable;
 
 /**
@@ -28,6 +29,7 @@ public final class BlurShader extends Shader {
     private final float mRadiusX;
     private final float mRadiusY;
     private final Shader mInputShader;
+    private final TileMode mEdgeTreatment;
 
     private long mNativeInputShader = 0;
 
@@ -35,22 +37,42 @@ public final class BlurShader extends Shader {
      * Create a {@link BlurShader} that blurs the contents of the optional input shader
      * with the specified radius along the x and y axis. If no input shader is provided
      * then all drawing commands issued with a {@link android.graphics.Paint} that this
-     * shader is installed in will be blurred
+     * shader is installed in will be blurred.
+     *
+     * This uses a default {@link TileMode#DECAL} for edge treatment
+     *
      * @param radiusX Radius of blur along the X axis
      * @param radiusY Radius of blur along the Y axis
      * @param inputShader Input shader that provides the content to be blurred
      */
     public BlurShader(float radiusX, float radiusY, @Nullable Shader inputShader) {
+        this(radiusX, radiusY, inputShader, TileMode.DECAL);
+    }
+
+    /**
+     * Create a {@link BlurShader} that blurs the contents of the optional input shader
+     * with the specified radius along the x and y axis. If no input shader is provided
+     * then all drawing commands issued with a {@link android.graphics.Paint} that this
+     * shader is installed in will be blurred
+     * @param radiusX Radius of blur along the X axis
+     * @param radiusY Radius of blur along the Y axis
+     * @param inputShader Input shader that provides the content to be blurred
+     * @param edgeTreatment Policy for how to blur content near edges of the blur shader
+     */
+    public BlurShader(float radiusX, float radiusY, @Nullable Shader inputShader,
+            @NonNull TileMode edgeTreatment) {
         mRadiusX = radiusX;
         mRadiusY = radiusY;
         mInputShader = inputShader;
+        mEdgeTreatment = edgeTreatment;
     }
 
     /** @hide **/
     @Override
     protected long createNativeInstance(long nativeMatrix) {
         mNativeInputShader = mInputShader != null ? mInputShader.getNativeInstance() : 0;
-        return nativeCreate(nativeMatrix, mRadiusX, mRadiusY, mNativeInputShader);
+        return nativeCreate(nativeMatrix, mRadiusX, mRadiusY, mNativeInputShader,
+                mEdgeTreatment.nativeInt);
     }
 
     /** @hide **/
@@ -61,5 +83,5 @@ public final class BlurShader extends Shader {
     }
 
     private static native long nativeCreate(long nativeMatrix, float radiusX, float radiusY,
-            long inputShader);
+            long inputShader, int edgeTreatment);
 }
diff --git a/graphics/java/android/graphics/Shader.java b/graphics/java/android/graphics/Shader.java
index 8154ebf1e508..d71ff1138b25 100644
--- a/graphics/java/android/graphics/Shader.java
+++ b/graphics/java/android/graphics/Shader.java
@@ -95,7 +95,11 @@ public class Shader {
          * repeat the shader's image horizontally and vertically, alternating
          * mirror images so that adjacent images always seam
          */
-        MIRROR  (2);
+        MIRROR(2),
+        /**
+         * Only draw within the original domain, return transparent-black everywhere else
+         */
+        DECAL(3);
 
         TileMode(int nativeInt) {
             this.nativeInt = nativeInt;
diff --git a/libs/hwui/jni/Shader.cpp b/libs/hwui/jni/Shader.cpp
index 7cb77233846f..0a194f9dd666 100644
--- a/libs/hwui/jni/Shader.cpp
+++ b/libs/hwui/jni/Shader.cpp
@@ -224,7 +224,7 @@ static jlong ComposeShader_create(JNIEnv* env, jobject o, jlong matrixPtr,
 ///////////////////////////////////////////////////////////////////////////////////////////////
 
 static jlong BlurShader_create(JNIEnv* env , jobject o, jlong matrixPtr, jfloat sigmaX,
-        jfloat sigmaY, jlong shaderHandle) {
+        jfloat sigmaY, jlong shaderHandle, jint edgeTreatment) {
     auto* matrix = reinterpret_cast<const SkMatrix*>(matrixPtr);
     auto* inputShader = reinterpret_cast<Shader*>(shaderHandle);
 
@@ -232,6 +232,7 @@ static jlong BlurShader_create(JNIEnv* env , jobject o, jlong matrixPtr, jfloat
                 sigmaX,
                 sigmaY,
                 inputShader,
+                static_cast<SkTileMode>(edgeTreatment),
                 matrix
             );
     return reinterpret_cast<jlong>(blurShader);
@@ -291,7 +292,7 @@ static const JNINativeMethod gBitmapShaderMethods[] = {
 };
 
 static const JNINativeMethod gBlurShaderMethods[] = {
-    { "nativeCreate",      "(JFFJ)J", (void*)BlurShader_create }
+    { "nativeCreate",      "(JFFJI)J", (void*)BlurShader_create }
 };
 
 static const JNINativeMethod gLinearGradientMethods[] = {
diff --git a/libs/hwui/shader/BlurShader.cpp b/libs/hwui/shader/BlurShader.cpp
index fa10be100bca..2abd8714204b 100644
--- a/libs/hwui/shader/BlurShader.cpp
+++ b/libs/hwui/shader/BlurShader.cpp
@@ -20,13 +20,14 @@
 #include "utils/Blur.h"
 
 namespace android::uirenderer {
-BlurShader::BlurShader(float radiusX, float radiusY, Shader* inputShader, const SkMatrix* matrix)
+BlurShader::BlurShader(float radiusX, float radiusY, Shader* inputShader, SkTileMode edgeTreatment,
+        const SkMatrix* matrix)
     : Shader(matrix)
     , skImageFilter(
             SkImageFilters::Blur(
                     Blur::convertRadiusToSigma(radiusX),
                     Blur::convertRadiusToSigma(radiusY),
-                    SkTileMode::kClamp,
+                    edgeTreatment,
                     inputShader ? inputShader->asSkImageFilter() : nullptr,
                     nullptr)
             ) { }
diff --git a/libs/hwui/shader/BlurShader.h b/libs/hwui/shader/BlurShader.h
index 9eb22bd11f4a..60a15898893e 100644
--- a/libs/hwui/shader/BlurShader.h
+++ b/libs/hwui/shader/BlurShader.h
@@ -30,8 +30,12 @@ public:
      *
      * This will blur the contents of the provided input shader if it is non-null, otherwise
      * the source bitmap will be blurred instead.
+     *
+     * The edge treatment parameter determines how content near the edges of the source is to
+     * participate in the blur
      */
-    BlurShader(float radiusX, float radiusY, Shader* inputShader, const SkMatrix* matrix);
+    BlurShader(float radiusX, float radiusY, Shader* inputShader, SkTileMode edgeTreatment,
+            const SkMatrix* matrix);
     ~BlurShader() override;
 protected:
     sk_sp<SkImageFilter> makeSkImageFilter() override;
diff --git a/non-updatable-api/current.txt b/non-updatable-api/current.txt
index 80300611c7f2..b9869e7faaee 100644
--- a/non-updatable-api/current.txt
+++ b/non-updatable-api/current.txt
@@ -14292,6 +14292,7 @@ package android.graphics {
 
   public final class BlurShader extends android.graphics.Shader {
     ctor public BlurShader(float, float, @Nullable android.graphics.Shader);
+    ctor public BlurShader(float, float, @Nullable android.graphics.Shader, @NonNull android.graphics.Shader.TileMode);
   }
 
   public class Camera {
@@ -15612,6 +15613,7 @@ package android.graphics {
 
   public enum Shader.TileMode {
     enum_constant public static final android.graphics.Shader.TileMode CLAMP;
+    enum_constant public static final android.graphics.Shader.TileMode DECAL;
     enum_constant public static final android.graphics.Shader.TileMode MIRROR;
     enum_constant public static final android.graphics.Shader.TileMode REPEAT;
   }