Add plumbing to support gradients in OpenGL renderer.

The LinearGradient class keeps a copy of the various parameters that
define the gradient. The copies are native arrays to avoid copying
Java arrays on every draw call. The gradient code path is implemented
until OpenGLRenderer::drawRect() (see TODO.) The actual gradient
implementation will be added in a latter change.

Change-Id: I9300d250ef5e2e9c2e097c3116ee71dfc9d752d8

3 files changed, 84 insertions, 11 deletions

diff --git a/core/java/android/view/GLES20Canvas.java b/core/java/android/view/GLES20Canvas.java
index 676aae3..ef9709e 100644
--- a/core/java/android/view/GLES20Canvas.java
+++ b/core/java/android/view/GLES20Canvas.java
@@ -631,7 +631,10 @@ class GLES20Canvas extends Canvas {
                         bs.mTileX, bs.mTileY, bs.mLocalMatrix);
                 return true;
             } else if (shader instanceof LinearGradient) {
-                // TODO: Implement
+                final LinearGradient ls = (LinearGradient) shader;
+                nSetupLinearShader(mRenderer, ls.native_instance, ls.bounds, ls.colors,
+                        ls.positions, ls.tileMode, ls.mLocalMatrix);
+                return true;
             } else if (shader instanceof RadialGradient) {
                 // TODO: Implement
             } else if (shader instanceof SweepGradient) {
@@ -640,8 +643,10 @@ class GLES20Canvas extends Canvas {
         }
         return false;
     }
-    
+
+    private native void nSetupLinearShader(int renderer, int shader, int bounds,
+            int colors, int positions, int tileMode, int localMatrix);
     private native void nSetupBitmapShader(int renderer, int shader, int bitmap,
             int tileX, int tileY, int matrix);
-    private native void nResetShader(int renderer);  
+    private native void nResetShader(int renderer);
 }
diff --git a/core/jni/android/graphics/Shader.cpp b/core/jni/android/graphics/Shader.cpp
index b09c62b..eb600c4 100644
--- a/core/jni/android/graphics/Shader.cpp
+++ b/core/jni/android/graphics/Shader.cpp
@@ -8,6 +8,13 @@
 #include "SkTemplates.h"
 #include "SkXfermode.h"
 
+static struct {
+    jclass clazz;
+    jfieldID bounds;
+    jfieldID colors;
+    jfieldID positions;
+} gLinearGradientClassInfo;
+
 static void ThrowIAE_IfNull(JNIEnv* env, void* ptr) {
     if (NULL == ptr) {
         doThrowIAE(env);
@@ -77,7 +84,14 @@ static SkShader* BitmapShader_constructor(JNIEnv* env, jobject, const SkBitmap*
     
 ///////////////////////////////////////////////////////////////////////////////////////////////
 
-static SkShader* LinearGradient_create1(JNIEnv* env, jobject,
+static void LinearGradient_destructor(JNIEnv* env, jobject o, SkShader* shader)
+{
+    delete reinterpret_cast<jfloat*>(env->GetIntField(o, gLinearGradientClassInfo.bounds));
+    delete reinterpret_cast<jint*>(env->GetIntField(o, gLinearGradientClassInfo.colors));
+    delete reinterpret_cast<jfloat*>(env->GetIntField(o, gLinearGradientClassInfo.positions));
+}
+
+static SkShader* LinearGradient_create1(JNIEnv* env, jobject o,
                                         float x0, float y0, float x1, float y1,
                                         jintArray colorArray, jfloatArray posArray, int tileMode)
 {
@@ -90,15 +104,31 @@ static SkShader* LinearGradient_create1(JNIEnv* env, jobject,
 
     SkAutoSTMalloc<8, SkScalar> storage(posArray ? count : 0);
     SkScalar*                   pos = NULL;
-    
+
+    jfloat* storedBounds = new jfloat[4];
+    storedBounds[0] = x0; storedBounds[1] = y0;
+    storedBounds[2] = x1; storedBounds[3] = y1;
+    jfloat* storedPositions = new jfloat[count];
+    jint* storedColors = new jint[count];
+    memcpy(storedColors, colorValues, count);
+
     if (posArray) {
         AutoJavaFloatArray autoPos(env, posArray, count);
         const float* posValues = autoPos.ptr();
         pos = (SkScalar*)storage.get();
-        for (size_t i = 0; i < count; i++)
+        for (size_t i = 0; i < count; i++) {
             pos[i] = SkFloatToScalar(posValues[i]);
+            storedPositions[i] = posValues[i];
+        }
+    } else {
+        storedPositions[0] = 0.0f;
+        storedPositions[1] = 1.0f;
     }
-
+    
+    env->SetIntField(o, gLinearGradientClassInfo.bounds, reinterpret_cast<jint>(storedBounds));
+    env->SetIntField(o, gLinearGradientClassInfo.colors, reinterpret_cast<jint>(storedColors));
+    env->SetIntField(o, gLinearGradientClassInfo.positions, reinterpret_cast<jint>(storedPositions));
+    
     SkShader* shader = SkGradientShader::CreateLinear(pts,
                                 reinterpret_cast<const SkColor*>(colorValues),
                                 pos, count,
@@ -109,7 +139,7 @@ static SkShader* LinearGradient_create1(JNIEnv* env, jobject,
     return shader;
 }
 
-static SkShader* LinearGradient_create2(JNIEnv* env, jobject,
+static SkShader* LinearGradient_create2(JNIEnv* env, jobject o,
                                         float x0, float y0, float x1, float y1,
                                         int color0, int color1, int tileMode)
 {
@@ -120,6 +150,22 @@ static SkShader* LinearGradient_create2(JNIEnv* env, jobject,
     SkColor colors[2];
     colors[0] = color0;
     colors[1] = color1;
+    
+    float* storedBounds = new float[4];
+    storedBounds[0] = x0; storedBounds[1] = y0;
+    storedBounds[2] = x1; storedBounds[3] = y1;
+    
+    float* storedPositions = new float[2];
+    storedPositions[0] = 0.0f;
+    storedPositions[1] = 1.0f;
+    
+    uint32_t* storedColors = new uint32_t[2];
+    storedColors[0] = color0;
+    storedColors[1] = color1;
+    
+    env->SetIntField(o, gLinearGradientClassInfo.bounds, reinterpret_cast<jint>(storedBounds));
+    env->SetIntField(o, gLinearGradientClassInfo.colors, reinterpret_cast<jint>(storedColors));
+    env->SetIntField(o, gLinearGradientClassInfo.positions, reinterpret_cast<jint>(storedPositions));
 
     SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, 2, (SkShader::TileMode)tileMode);
     ThrowIAE_IfNull(env, s);
@@ -254,8 +300,9 @@ static JNINativeMethod gBitmapShaderMethods[] = {
 };
 
 static JNINativeMethod gLinearGradientMethods[] = {
-    { "nativeCreate1",  "(FFFF[I[FI)I", (void*)LinearGradient_create1   },
-    { "nativeCreate2",  "(FFFFIII)I",   (void*)LinearGradient_create2   }
+    { "nativeDestructor", "(I)V",         (void*)LinearGradient_destructor },
+    { "nativeCreate1",    "(FFFF[I[FI)I", (void*)LinearGradient_create1    },
+    { "nativeCreate2",    "(FFFFIII)I",   (void*)LinearGradient_create2    }
 };
 
 static JNINativeMethod gRadialGradientMethods[] = {
@@ -278,6 +325,15 @@ static JNINativeMethod gComposeShaderMethods[] = {
 #define REG(env, name, array)                                                                       \
     result = android::AndroidRuntime::registerNativeMethods(env, name, array, SK_ARRAY_COUNT(array));  \
     if (result < 0) return result
+    
+#define FIND_CLASS(var, className) \
+        var = env->FindClass(className); \
+        LOG_FATAL_IF(! var, "Unable to find class " className); \
+        var = jclass(env->NewGlobalRef(var));
+
+#define GET_FIELD_ID(var, clazz, fieldName, fieldType) \
+        var = env->GetFieldID(clazz, fieldName, fieldType); \
+        LOG_FATAL_IF(! var, "Unable to find field " fieldName);
 
 int register_android_graphics_Shader(JNIEnv* env);
 int register_android_graphics_Shader(JNIEnv* env)
@@ -292,6 +348,11 @@ int register_android_graphics_Shader(JNIEnv* env)
     REG(env, "android/graphics/SweepGradient", gSweepGradientMethods);
     REG(env, "android/graphics/ComposeShader", gComposeShaderMethods);
     
+    FIND_CLASS(gLinearGradientClassInfo.clazz, "android/graphics/LinearGradient");
+    GET_FIELD_ID(gLinearGradientClassInfo.bounds, gLinearGradientClassInfo.clazz, "bounds", "I");
+    GET_FIELD_ID(gLinearGradientClassInfo.colors, gLinearGradientClassInfo.clazz, "colors", "I");
+    GET_FIELD_ID(gLinearGradientClassInfo.positions, gLinearGradientClassInfo.clazz, "positions", "I");
+    
     return result;
 }
 
diff --git a/core/jni/android_view_GLES20Canvas.cpp b/core/jni/android_view_GLES20Canvas.cpp
index e5aa5dd..f952702 100644
--- a/core/jni/android_view_GLES20Canvas.cpp
+++ b/core/jni/android_view_GLES20Canvas.cpp
@@ -201,7 +201,6 @@ static void android_view_GLES20Canvas_drawBitmapMatrix(JNIEnv* env, jobject canv
 static void android_view_GLES20Canvas_drawPatch(JNIEnv* env, jobject canvas,
         OpenGLRenderer* renderer, SkBitmap* bitmap, jbyteArray chunks,
         float left, float top, float right, float bottom, SkPaint* paint) {
-
     jbyte* storage = env->GetByteArrayElements(chunks, NULL);
     Res_png_9patch* patch = reinterpret_cast<Res_png_9patch*>(storage);
     Res_png_9patch::deserialize(patch);
@@ -239,6 +238,13 @@ static void android_view_GLES20Canvas_setupBitmapShader(JNIEnv* env, jobject can
             (shader->getFlags() & SkShader::kOpaqueAlpha_Flag) == 0);
 }
 
+static void android_view_GLES20Canvas_setupLinearShader(JNIEnv* env, jobject canvas,
+        OpenGLRenderer* renderer, SkShader* shader, float* bounds, uint32_t* colors,
+        float* positions, SkShader::TileMode tileMode, SkMatrix* matrix) {
+    renderer->setupLinearGradientShader(bounds, colors, positions, tileMode, matrix,
+            (shader->getFlags() & SkShader::kOpaqueAlpha_Flag) == 0);
+}
+
 // ----------------------------------------------------------------------------
 // JNI Glue
 // ----------------------------------------------------------------------------
@@ -280,6 +286,7 @@ static JNINativeMethod gMethods[] = {
 
     {   "nResetShader",       "(I)V",            (void*) android_view_GLES20Canvas_resetShader },
     {   "nSetupBitmapShader", "(IIIIII)V",       (void*) android_view_GLES20Canvas_setupBitmapShader },
+    {   "nSetupLinearShader", "(IIIIIII)V",      (void*) android_view_GLES20Canvas_setupLinearShader },
 
     {   "nGetClipBounds",     "(ILandroid/graphics/Rect;)Z",
             (void*) android_view_GLES20Canvas_getClipBounds },