Render ImageWallpaper with OpenGL ES and apply visual effects. (Fix bug)

We have to render image wallpaper with OpenGL ES to apply some amazing
visual effects.

Bug: 122803209
Bug: 124073420
Bug: 123616712
Bug: 123615467
Test: Manually.
Change-Id: I0123d4ba2acb5a84b709c0468910e006c8e49563

12 files changed, 914 insertions, 9 deletions

diff --git a/packages/SystemUI/AndroidManifest.xml b/packages/SystemUI/AndroidManifest.xml
index 4a5388be2c1e..265d464d9c71 100644
--- a/packages/SystemUI/AndroidManifest.xml
+++ b/packages/SystemUI/AndroidManifest.xml
@@ -22,6 +22,11 @@
         android:sharedUserId="android.uid.systemui"
         coreApp="true">
 
+    <!-- Using OpenGL ES 2.0 -->
+    <uses-feature
+        android:glEsVersion="0x00020000"
+        android:required="true" />
+
     <!-- SysUI must be the one to define this permission; its name is
          referenced by the core OS. -->
     <permission android:name="android.permission.systemui.IDENTITY"
diff --git a/packages/SystemUI/res/raw/image_wallpaper_fragment_shader.glsl b/packages/SystemUI/res/raw/image_wallpaper_fragment_shader.glsl
new file mode 100644
index 000000000000..586cdf3fbaae
--- /dev/null
+++ b/packages/SystemUI/res/raw/image_wallpaper_fragment_shader.glsl
@@ -0,0 +1,27 @@
+precision mediump float;
+
+uniform sampler2D uTexture;
+uniform float uCenterReveal;
+uniform float uReveal;
+uniform float uAod2Opacity;
+varying vec2 vTextureCoordinates;
+
+vec3 luminosity(vec3 color) {
+    float lum = 0.2126 * color.r + 0.7152 * color.g + 0.0722 * color.b;
+    return vec3(lum);
+}
+
+vec4 transform(vec3 diffuse) {
+    // TODO: Add well comments here, tracking on b/123615467.
+    vec3 lum = luminosity(diffuse);
+    diffuse = mix(diffuse, lum, smoothstep(0., uCenterReveal, uReveal));
+    float val = mix(uReveal, uCenterReveal, step(uCenterReveal, uReveal));
+    diffuse = smoothstep(val, 1.0, diffuse);
+    diffuse *= uAod2Opacity * (1. - smoothstep(uCenterReveal, 1., uReveal));
+    return vec4(diffuse.r, diffuse.g, diffuse.b, 1.);
+}
+
+void main() {
+    vec4 fragColor = texture2D(uTexture, vTextureCoordinates);
+    gl_FragColor = transform(fragColor.rgb);
+}
\ No newline at end of file
diff --git a/packages/SystemUI/res/raw/image_wallpaper_vertex_shader.glsl b/packages/SystemUI/res/raw/image_wallpaper_vertex_shader.glsl
new file mode 100644
index 000000000000..4393e2bb0ebf
--- /dev/null
+++ b/packages/SystemUI/res/raw/image_wallpaper_vertex_shader.glsl
@@ -0,0 +1,8 @@
+attribute vec4 aPosition;
+attribute vec2 aTextureCoordinates;
+varying vec2 vTextureCoordinates;
+
+void main() {
+    vTextureCoordinates = aTextureCoordinates;
+    gl_Position = aPosition;
+}
\ No newline at end of file
diff --git a/packages/SystemUI/src/com/android/systemui/ImageWallpaper.java b/packages/SystemUI/src/com/android/systemui/ImageWallpaper.java
index 2aecc24e83c0..7e645ab77a63 100644
--- a/packages/SystemUI/src/com/android/systemui/ImageWallpaper.java
+++ b/packages/SystemUI/src/com/android/systemui/ImageWallpaper.java
@@ -28,7 +28,9 @@ import android.graphics.Rect;
 import android.graphics.RectF;
 import android.graphics.Region.Op;
 import android.hardware.display.DisplayManager;
+import android.opengl.GLSurfaceView;
 import android.os.AsyncTask;
+import android.os.Build;
 import android.os.Handler;
 import android.os.Trace;
 import android.service.wallpaper.WallpaperService;
@@ -39,6 +41,7 @@ import android.view.Surface;
 import android.view.SurfaceHolder;
 
 import com.android.internal.annotations.VisibleForTesting;
+import com.android.systemui.glwallpaper.ImageWallpaperRenderer;
 
 import java.io.FileDescriptor;
 import java.io.IOException;
@@ -73,10 +76,78 @@ public class ImageWallpaper extends WallpaperService {
 
     @Override
     public Engine onCreateEngine() {
-        mEngine = new DrawableEngine();
-        return mEngine;
+        if (Build.IS_DEBUGGABLE) {
+            Log.v(TAG, "We are using GLEngine");
+        }
+        return new GLEngine(this);
+    }
+
+    class GLEngine extends Engine {
+        private GLWallpaperSurfaceView mWallpaperSurfaceView;
+
+        GLEngine(Context context) {
+            mWallpaperSurfaceView = new GLWallpaperSurfaceView(context);
+            mWallpaperSurfaceView.setRenderer(
+                    new ImageWallpaperRenderer(context, mWallpaperSurfaceView));
+            mWallpaperSurfaceView.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
+            setOffsetNotificationsEnabled(true);
+        }
+
+        @Override
+        public void onAmbientModeChanged(boolean inAmbientMode, long animationDuration) {
+            if (mWallpaperSurfaceView != null) {
+                mWallpaperSurfaceView.notifyAmbientModeChanged(inAmbientMode, animationDuration);
+            }
+        }
+
+        @Override
+        public void onOffsetsChanged(float xOffset, float yOffset, float xOffsetStep,
+                float yOffsetStep, int xPixelOffset, int yPixelOffset) {
+            if (mWallpaperSurfaceView != null) {
+                mWallpaperSurfaceView.notifyOffsetsChanged(xOffset, yOffset);
+            }
+        }
+
+        private class GLWallpaperSurfaceView extends GLSurfaceView implements ImageGLView {
+            private WallpaperStatusListener mWallpaperChangedListener;
+
+            GLWallpaperSurfaceView(Context context) {
+                super(context);
+                setEGLContextClientVersion(2);
+            }
+
+            @Override
+            public SurfaceHolder getHolder() {
+                return getSurfaceHolder();
+            }
+
+            @Override
+            public void setRenderer(Renderer renderer) {
+                super.setRenderer(renderer);
+                mWallpaperChangedListener = (WallpaperStatusListener) renderer;
+            }
+
+            private void notifyAmbientModeChanged(boolean inAmbient, long duration) {
+                if (mWallpaperChangedListener != null) {
+                    mWallpaperChangedListener.onAmbientModeChanged(inAmbient, duration);
+                }
+            }
+
+            private void notifyOffsetsChanged(float xOffset, float yOffset) {
+                if (mWallpaperChangedListener != null) {
+                    mWallpaperChangedListener.onOffsetsChanged(
+                            xOffset, yOffset, getHolder().getSurfaceFrame());
+                }
+            }
+
+            @Override
+            public void render() {
+                requestRender();
+            }
+        }
     }
 
+    // TODO: Remove this engine, tracking on b/123617158.
     class DrawableEngine extends Engine {
         private final Runnable mUnloadWallpaperCallback = () -> {
             unloadWallpaper(false /* forgetSize */);
@@ -564,4 +635,35 @@ public class ImageWallpaper extends WallpaperService {
             }
         }
     }
+
+    /**
+     * A listener to trace status of image wallpaper.
+     */
+    public interface WallpaperStatusListener {
+
+        /**
+         * Called back while ambient mode changes.
+         * @param inAmbientMode true if is in ambient mode, false otherwise.
+         * @param duration the duration of animation.
+         */
+        void onAmbientModeChanged(boolean inAmbientMode, long duration);
+
+        /**
+         * Called back while wallpaper offsets.
+         * @param xOffset The offset portion along x.
+         * @param yOffset The offset portion along y.
+         */
+        void onOffsetsChanged(float xOffset, float yOffset, Rect frame);
+    }
+
+    /**
+     * An abstraction for view of GLRenderer.
+     */
+    public interface ImageGLView {
+
+        /**
+         * Ask the view to render.
+         */
+        void render();
+    }
 }
diff --git a/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageGLProgram.java b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageGLProgram.java
new file mode 100644
index 000000000000..d03b00bcfc85
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageGLProgram.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.glwallpaper;
+
+import static android.opengl.GLES20.GL_FRAGMENT_SHADER;
+import static android.opengl.GLES20.GL_VERTEX_SHADER;
+import static android.opengl.GLES20.glAttachShader;
+import static android.opengl.GLES20.glCompileShader;
+import static android.opengl.GLES20.glCreateProgram;
+import static android.opengl.GLES20.glCreateShader;
+import static android.opengl.GLES20.glGetAttribLocation;
+import static android.opengl.GLES20.glGetUniformLocation;
+import static android.opengl.GLES20.glLinkProgram;
+import static android.opengl.GLES20.glShaderSource;
+import static android.opengl.GLES20.glUseProgram;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.util.Log;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+/**
+ * This class takes charge of linking shader codes and then return a handle for OpenGL ES program.
+ */
+class ImageGLProgram {
+    private static final String TAG = ImageGLProgram.class.getSimpleName();
+
+    private Context mContext;
+    private int mProgramHandle;
+
+    ImageGLProgram(Context context) {
+        mContext = context.getApplicationContext();
+    }
+
+    private int loadShaderProgram(int vertexId, int fragmentId) {
+        final String vertexSrc = getShaderResource(vertexId);
+        final String fragmentSrc = getShaderResource(fragmentId);
+        final int vertexHandle = getShaderHandle(GL_VERTEX_SHADER, vertexSrc);
+        final int fragmentHandle = getShaderHandle(GL_FRAGMENT_SHADER, fragmentSrc);
+        return getProgramHandle(vertexHandle, fragmentHandle);
+    }
+
+    private String getShaderResource(int shaderId) {
+        Resources res = mContext.getResources();
+        StringBuilder code = new StringBuilder();
+
+        try (BufferedReader reader = new BufferedReader(
+                new InputStreamReader(res.openRawResource(shaderId)))) {
+            String nextLine;
+            while ((nextLine = reader.readLine()) != null) {
+                code.append(nextLine).append("\n");
+            }
+        } catch (IOException | Resources.NotFoundException ex) {
+            Log.d(TAG, "Can not read the shader source", ex);
+            code = null;
+        }
+
+        return code == null ? "" : code.toString();
+    }
+
+    private int getShaderHandle(int type, String src) {
+        final int shader = glCreateShader(type);
+        if (shader == 0) {
+            Log.d(TAG, "Create shader failed, type=" + type);
+            return 0;
+        }
+        glShaderSource(shader, src);
+        glCompileShader(shader);
+        return shader;
+    }
+
+    private int getProgramHandle(int vertexHandle, int fragmentHandle) {
+        final int program = glCreateProgram();
+        if (program == 0) {
+            Log.d(TAG, "Can not create OpenGL ES program");
+            return 0;
+        }
+
+        glAttachShader(program, vertexHandle);
+        glAttachShader(program, fragmentHandle);
+        glLinkProgram(program);
+        return program;
+    }
+
+    boolean useGLProgram(int vertexResId, int fragmentResId) {
+        mProgramHandle = loadShaderProgram(vertexResId, fragmentResId);
+        glUseProgram(mProgramHandle);
+        return true;
+    }
+
+    int getAttributeHandle(String name) {
+        return glGetAttribLocation(mProgramHandle, name);
+    }
+
+    int getUniformHandle(String name) {
+        return glGetUniformLocation(mProgramHandle, name);
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageGLWallpaper.java b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageGLWallpaper.java
new file mode 100644
index 000000000000..19d85b155cba
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageGLWallpaper.java
@@ -0,0 +1,259 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.glwallpaper;
+
+import static android.opengl.GLES20.GL_FLOAT;
+import static android.opengl.GLES20.GL_LINEAR;
+import static android.opengl.GLES20.GL_TEXTURE0;
+import static android.opengl.GLES20.GL_TEXTURE_2D;
+import static android.opengl.GLES20.GL_TEXTURE_MAG_FILTER;
+import static android.opengl.GLES20.GL_TEXTURE_MIN_FILTER;
+import static android.opengl.GLES20.GL_TRIANGLES;
+import static android.opengl.GLES20.glActiveTexture;
+import static android.opengl.GLES20.glBindTexture;
+import static android.opengl.GLES20.glDrawArrays;
+import static android.opengl.GLES20.glEnableVertexAttribArray;
+import static android.opengl.GLES20.glGenTextures;
+import static android.opengl.GLES20.glTexParameteri;
+import static android.opengl.GLES20.glUniform1i;
+import static android.opengl.GLES20.glVertexAttribPointer;
+
+import android.graphics.Bitmap;
+import android.opengl.GLUtils;
+import android.os.Build;
+import android.util.Log;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.nio.FloatBuffer;
+
+/**
+ * This class takes charge of the geometry data like vertices and texture coordinates.
+ * It delivers these data to opengl runtime and triggers draw calls if necessary.
+ */
+class ImageGLWallpaper {
+    private static final String TAG = ImageGLWallpaper.class.getSimpleName();
+
+    static final String A_POSITION = "aPosition";
+    static final String A_TEXTURE_COORDINATES = "aTextureCoordinates";
+    static final String U_CENTER_REVEAL = "uCenterReveal";
+    static final String U_REVEAL = "uReveal";
+    static final String U_AOD2OPACITY = "uAod2Opacity";
+    static final String U_TEXTURE = "uTexture";
+
+    private static final int HANDLE_UNDEFINED = -1;
+    private static final int POSITION_COMPONENT_COUNT = 2;
+    private static final int TEXTURE_COMPONENT_COUNT = 2;
+    private static final int BYTES_PER_FLOAT = 4;
+
+    // Vertices to define the square with 2 triangles.
+    private static final float[] VERTICES = {
+            -1.0f,  -1.0f,
+            +1.0f,  -1.0f,
+            +1.0f,  +1.0f,
+            +1.0f,  +1.0f,
+            -1.0f,  +1.0f,
+            -1.0f,  -1.0f
+    };
+
+    // Texture coordinates that maps to vertices.
+    private static final float[] TEXTURES = {
+            0f, 1f,
+            1f, 1f,
+            1f, 0f,
+            1f, 0f,
+            0f, 0f,
+            0f, 1f
+    };
+
+    private final FloatBuffer mVertexBuffer;
+    private final FloatBuffer mTextureBuffer;
+    private final ImageGLProgram mProgram;
+
+    private int mAttrPosition;
+    private int mAttrTextureCoordinates;
+    private int mUniAod2Opacity;
+    private int mUniCenterReveal;
+    private int mUniReveal;
+    private int mUniTexture;
+    private int mTextureId;
+
+    ImageGLWallpaper(ImageGLProgram program) {
+        mProgram = program;
+
+        // Create an float array in opengles runtime (native) and put vertex data.
+        mVertexBuffer = ByteBuffer.allocateDirect(VERTICES.length * BYTES_PER_FLOAT)
+            .order(ByteOrder.nativeOrder())
+            .asFloatBuffer();
+        mVertexBuffer.put(VERTICES);
+        mVertexBuffer.position(0);
+
+        // Create an float array in opengles runtime (native) and put texture data.
+        mTextureBuffer = ByteBuffer.allocateDirect(TEXTURES.length * BYTES_PER_FLOAT)
+            .order(ByteOrder.nativeOrder())
+            .asFloatBuffer();
+        mTextureBuffer.put(TEXTURES);
+        mTextureBuffer.position(0);
+    }
+
+    void setup() {
+        setupAttributes();
+        setupUniforms();
+    }
+
+    private void setupAttributes() {
+        mAttrPosition = mProgram.getAttributeHandle(A_POSITION);
+        mVertexBuffer.position(0);
+        glVertexAttribPointer(mAttrPosition, POSITION_COMPONENT_COUNT, GL_FLOAT,
+                false, 0, mVertexBuffer);
+        glEnableVertexAttribArray(mAttrPosition);
+
+        mAttrTextureCoordinates = mProgram.getAttributeHandle(A_TEXTURE_COORDINATES);
+        mTextureBuffer.position(0);
+        glVertexAttribPointer(mAttrTextureCoordinates, TEXTURE_COMPONENT_COUNT, GL_FLOAT,
+                false, 0, mTextureBuffer);
+        glEnableVertexAttribArray(mAttrTextureCoordinates);
+    }
+
+    private void setupUniforms() {
+        mUniAod2Opacity = mProgram.getUniformHandle(U_AOD2OPACITY);
+        mUniCenterReveal = mProgram.getUniformHandle(U_CENTER_REVEAL);
+        mUniReveal = mProgram.getUniformHandle(U_REVEAL);
+        mUniTexture = mProgram.getUniformHandle(U_TEXTURE);
+    }
+
+    int getHandle(String name) {
+        switch (name) {
+            case A_POSITION:
+                return mAttrPosition;
+            case A_TEXTURE_COORDINATES:
+                return mAttrTextureCoordinates;
+            case U_AOD2OPACITY:
+                return mUniAod2Opacity;
+            case U_CENTER_REVEAL:
+                return mUniCenterReveal;
+            case U_REVEAL:
+                return mUniReveal;
+            case U_TEXTURE:
+                return mUniTexture;
+            default:
+                return HANDLE_UNDEFINED;
+        }
+    }
+
+    void draw() {
+        glDrawArrays(GL_TRIANGLES, 0, VERTICES.length / 2);
+    }
+
+    void setupTexture(Bitmap bitmap) {
+        final int[] tids = new int[1];
+
+        if (bitmap == null) {
+            Log.w(TAG, "setupTexture: invalid bitmap");
+            return;
+        }
+
+        // Generate one texture object and store the id in tids[0].
+        glGenTextures(1, tids, 0);
+        if (tids[0] == 0) {
+            Log.w(TAG, "setupTexture: glGenTextures() failed");
+            return;
+        }
+
+        // Bind a named texture to a texturing target.
+        glBindTexture(GL_TEXTURE_2D, tids[0]);
+        // Load the bitmap data and copy it over into the texture object that is currently bound.
+        GLUtils.texImage2D(GL_TEXTURE_2D, 0, bitmap, 0);
+        // Use bilinear texture filtering when minification.
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        // Use bilinear texture filtering when magnification.
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+        mTextureId = tids[0];
+    }
+
+    void useTexture() {
+        // Set the active texture unit to texture unit 0.
+        glActiveTexture(GL_TEXTURE0);
+        // Bind the texture to this unit.
+        glBindTexture(GL_TEXTURE_2D, mTextureId);
+        // Let the texture sampler in fragment shader to read form this texture unit.
+        glUniform1i(mUniTexture, 0);
+    }
+
+    void adjustTextureCoordinates(Bitmap bitmap, int surfaceWidth, int surfaceHeight,
+            float xOffset, float yOffset) {
+        if (bitmap == null) {
+            Log.d(TAG, "adjustTextureCoordinates: invalid bitmap");
+            return;
+        }
+
+        int bitmapWidth = bitmap.getWidth();
+        int bitmapHeight = bitmap.getHeight();
+        float ratioW = 1f;
+        float ratioH = 1f;
+        float rX = 0f;
+        float rY = 0f;
+        float[] coordinates = null;
+
+        final boolean adjustWidth = bitmapWidth > surfaceWidth;
+        final boolean adjustHeight = bitmapHeight > surfaceHeight;
+
+        if (adjustWidth || adjustHeight) {
+            coordinates = TEXTURES.clone();
+        }
+
+        if (adjustWidth) {
+            float x = (float) Math.round((bitmapWidth - surfaceWidth) * xOffset) / bitmapWidth;
+            ratioW = (float) surfaceWidth / bitmapWidth;
+            float referenceX = x + ratioW > 1f ? 1f - ratioW : x;
+            for (int i = 0; i < coordinates.length; i += 2) {
+                if (i == 2 || i == 4 || i == 6) {
+                    coordinates[i] = Math.min(1f, referenceX + ratioW);
+                } else {
+                    coordinates[i] = referenceX;
+                }
+            }
+            rX = referenceX;
+        }
+
+
+        if (adjustHeight) {
+            float y = (float) Math.round((bitmapHeight - surfaceHeight) * yOffset) / bitmapHeight;
+            ratioH = (float) surfaceHeight / bitmapHeight;
+            float referenceY = y + ratioH > 1f ? 1f - ratioH : y;
+            for (int i = 1; i < coordinates.length; i += 2) {
+                if (i == 1 || i == 3 || i == 11) {
+                    coordinates[i] = Math.min(1f, referenceY + ratioH);
+                } else {
+                    coordinates[i] = referenceY;
+                }
+            }
+            rY = referenceY;
+        }
+
+        if (adjustWidth || adjustHeight) {
+            if (Build.IS_DEBUGGABLE) {
+                Log.d(TAG, "adjustTextureCoordinates: sW=" + surfaceWidth + ", sH=" + surfaceHeight
+                        + ", bW=" + bitmapWidth + ", bH=" + bitmapHeight
+                        + ", rW=" + ratioW + ", rH=" + ratioH + ", rX=" + rX + ", rY=" + rY);
+            }
+            mTextureBuffer.put(coordinates);
+            mTextureBuffer.position(0);
+        }
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageProcessHelper.java b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageProcessHelper.java
new file mode 100644
index 000000000000..477e7d7ebf72
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageProcessHelper.java
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.glwallpaper;
+
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.ColorMatrix;
+import android.graphics.ColorMatrixColorFilter;
+import android.graphics.Matrix;
+import android.graphics.Paint;
+import android.os.AsyncTask;
+import android.os.Handler;
+import android.os.Handler.Callback;
+import android.os.Message;
+import android.util.Log;
+
+/**
+ * A helper class that computes histogram and percentile 85 from a bitmap.
+ * Percentile 85 will be computed each time the user picks a new image wallpaper.
+ */
+class ImageProcessHelper {
+    private static final String TAG = ImageProcessHelper.class.getSimpleName();
+    private static final float DEFAULT_PER85 = 0.8f;
+    private static final int MSG_UPDATE_PER85 = 1;
+
+    /**
+     * This color matrix will be applied to each pixel to get luminance from rgb by below formula:
+     * Luminance = .2126f * r + .7152f * g + .0722f * b.
+     */
+    private static final float[] LUMINOSITY_MATRIX = new float[] {
+            .2126f,     .0000f,     .0000f,     .0000f,     .0000f,
+            .0000f,     .7152f,     .0000f,     .0000f,     .0000f,
+            .0000f,     .0000f,     .0722f,     .0000f,     .0000f,
+            .0000f,     .0000f,     .0000f,     1.000f,     .0000f
+    };
+
+    private final Handler mHandler = new Handler(new Callback() {
+        @Override
+        public boolean handleMessage(Message msg) {
+            switch (msg.what) {
+                case MSG_UPDATE_PER85:
+                    mPer85 = (float) msg.obj;
+                    return true;
+                default:
+                    return false;
+            }
+        }
+    });
+
+    private float mPer85 = DEFAULT_PER85;
+
+    void startComputingPercentile85(Bitmap bitmap) {
+        new Per85ComputeTask(mHandler).execute(bitmap);
+    }
+
+    float getPercentile85() {
+        return mPer85;
+    }
+
+    private static class Per85ComputeTask extends AsyncTask<Bitmap, Void, Float> {
+        private Handler mUpdateHandler;
+
+        Per85ComputeTask(Handler handler) {
+            super(handler);
+            mUpdateHandler = handler;
+        }
+
+        @Override
+        protected Float doInBackground(Bitmap... bitmaps) {
+            Bitmap bitmap = bitmaps[0];
+            if (bitmap != null) {
+                int[] histogram = processHistogram(bitmap);
+                return computePercentile85(bitmap, histogram);
+            }
+            Log.e(TAG, "Per85ComputeTask: Can't get bitmap");
+            return DEFAULT_PER85;
+        }
+
+        @Override
+        protected void onPostExecute(Float result) {
+            Message msg = mUpdateHandler.obtainMessage(MSG_UPDATE_PER85, result);
+            mUpdateHandler.sendMessage(msg);
+        }
+
+        private int[] processHistogram(Bitmap bitmap) {
+            int width = bitmap.getWidth();
+            int height = bitmap.getHeight();
+
+            Bitmap target = Bitmap.createBitmap(width, height, bitmap.getConfig());
+            Canvas canvas = new Canvas(target);
+            ColorMatrix cm = new ColorMatrix(LUMINOSITY_MATRIX);
+            Paint paint = new Paint();
+            paint.setColorFilter(new ColorMatrixColorFilter(cm));
+            canvas.drawBitmap(bitmap, new Matrix(), paint);
+
+            // TODO: Fine tune the performance here, tracking on b/123615079.
+            int[] histogram = new int[256];
+            for (int row = 0; row < height; row++) {
+                for (int col = 0; col < width; col++) {
+                    int pixel = target.getPixel(col, row);
+                    int y = Color.red(pixel) + Color.green(pixel) + Color.blue(pixel);
+                    histogram[y]++;
+                }
+            }
+
+            return histogram;
+        }
+
+        private float computePercentile85(Bitmap bitmap, int[] histogram) {
+            float per85 = DEFAULT_PER85;
+            int pixelCount = bitmap.getWidth() * bitmap.getHeight();
+            float[] acc = new float[256];
+            for (int i = 0; i < acc.length; i++) {
+                acc[i] = (float) histogram[i] / pixelCount;
+                float prev = i == 0 ? 0f : acc[i - 1];
+                float next = acc[i];
+                float idx = (float) (i + 1) / 255;
+                float sum = prev + next;
+                if (prev < 0.85f && sum >= 0.85f) {
+                    per85 = idx;
+                }
+                if (i > 0) {
+                    acc[i] += acc[i - 1];
+                }
+            }
+            return per85;
+        }
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageRevealHelper.java b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageRevealHelper.java
new file mode 100644
index 000000000000..5914236ab349
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageRevealHelper.java
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.glwallpaper;
+
+import android.animation.Animator;
+import android.animation.AnimatorListenerAdapter;
+import android.animation.ValueAnimator;
+
+import com.android.systemui.Interpolators;
+
+/**
+ * Use ValueAnimator and appropriate interpolator to control the progress of reveal transition.
+ * The transition will happen while getting awake and quit events.
+ */
+class ImageRevealHelper {
+    private static final String TAG = ImageRevealHelper.class.getSimpleName();
+    private static final float MAX_REVEAL = 0f;
+    private static final float MIN_REVEAL = 1f;
+
+    private final ValueAnimator mAnimator;
+    private final RevealStateListener mRevealListener;
+    private float mReveal = MAX_REVEAL;
+    private boolean mAwake = false;
+
+    ImageRevealHelper(RevealStateListener listener) {
+        mRevealListener = listener;
+        mAnimator = ValueAnimator.ofFloat();
+        mAnimator.setInterpolator(Interpolators.FAST_OUT_SLOW_IN);
+        mAnimator.addUpdateListener(animator -> {
+            mReveal = (float) animator.getAnimatedValue();
+            if (mRevealListener != null) {
+                mRevealListener.onRevealStateChanged();
+            }
+        });
+        mAnimator.addListener(new AnimatorListenerAdapter() {
+            private boolean mIsCanceled;
+
+            @Override
+            public void onAnimationCancel(Animator animation) {
+                mIsCanceled = true;
+            }
+
+            @Override
+            public void onAnimationEnd(Animator animation) {
+                if (!mIsCanceled) {
+                    mAwake = !mAwake;
+                }
+                mIsCanceled = false;
+            }
+        });
+    }
+
+    private void animate() {
+        mAnimator.cancel();
+        mAnimator.setFloatValues(mReveal, !mAwake ? MIN_REVEAL : MAX_REVEAL);
+        mAnimator.start();
+    }
+
+    public float getReveal() {
+        return mReveal;
+    }
+
+    public boolean isAwake() {
+        return mAwake;
+    }
+
+    void updateAwake(boolean awake, long duration) {
+        mAwake = awake;
+        mAnimator.setDuration(duration);
+        animate();
+    }
+
+    /**
+     * A listener to trace value changes of reveal.
+     */
+    public interface RevealStateListener {
+
+        /**
+         * Called back while reveal status changes.
+         */
+        void onRevealStateChanged();
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageWallpaperRenderer.java b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageWallpaperRenderer.java
new file mode 100644
index 000000000000..991b1161dde2
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/glwallpaper/ImageWallpaperRenderer.java
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.glwallpaper;
+
+import static android.opengl.GLES20.GL_COLOR_BUFFER_BIT;
+import static android.opengl.GLES20.glClear;
+import static android.opengl.GLES20.glClearColor;
+import static android.opengl.GLES20.glUniform1f;
+import static android.opengl.GLES20.glViewport;
+
+import android.app.WallpaperManager;
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Rect;
+import android.opengl.GLSurfaceView;
+import android.os.Build;
+import android.util.Log;
+
+import com.android.systemui.ImageWallpaper;
+import com.android.systemui.ImageWallpaper.ImageGLView;
+import com.android.systemui.R;
+
+import javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.opengles.GL10;
+
+/**
+ * A GL renderer for image wallpaper.
+ */
+public class ImageWallpaperRenderer implements GLSurfaceView.Renderer,
+        ImageWallpaper.WallpaperStatusListener, ImageRevealHelper.RevealStateListener {
+    private static final String TAG = ImageWallpaperRenderer.class.getSimpleName();
+
+    private final WallpaperManager mWallpaperManager;
+    private final ImageGLProgram mProgram;
+    private final ImageGLWallpaper mWallpaper;
+    private final ImageProcessHelper mImageProcessHelper;
+    private final ImageRevealHelper mImageRevealHelper;
+    private final ImageGLView mGLView;
+    private float mXOffset = 0f;
+    private float mYOffset = 0f;
+
+    public ImageWallpaperRenderer(Context context, ImageGLView glView) {
+        mWallpaperManager = context.getSystemService(WallpaperManager.class);
+        if (mWallpaperManager == null) {
+            Log.w(TAG, "WallpaperManager not available");
+        }
+
+        mProgram = new ImageGLProgram(context);
+        mWallpaper = new ImageGLWallpaper(mProgram);
+        mImageProcessHelper = new ImageProcessHelper();
+        mImageRevealHelper = new ImageRevealHelper(this);
+        mGLView = glView;
+
+        if (mWallpaperManager != null) {
+            // Compute per85 as transition threshold, this is an async work.
+            mImageProcessHelper.startComputingPercentile85(mWallpaperManager.getBitmap());
+        }
+    }
+
+    @Override
+    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
+        glClearColor(0f, 0f, 0f, 1.0f);
+        mProgram.useGLProgram(
+                R.raw.image_wallpaper_vertex_shader, R.raw.image_wallpaper_fragment_shader);
+        mWallpaper.setup();
+        mWallpaper.setupTexture(mWallpaperManager.getBitmap());
+    }
+
+    @Override
+    public void onSurfaceChanged(GL10 gl, int width, int height) {
+        glViewport(0, 0, width, height);
+        if (Build.IS_DEBUGGABLE) {
+            Log.d(TAG, "onSurfaceChanged: width=" + width + ", height=" + height
+                    + ", xOffset=" + mXOffset + ", yOffset=" + mYOffset);
+        }
+        mWallpaper.adjustTextureCoordinates(mWallpaperManager.getBitmap(),
+                width, height, mXOffset, mYOffset);
+    }
+
+    @Override
+    public void onDrawFrame(GL10 gl) {
+        float threshold = mImageProcessHelper.getPercentile85();
+        float reveal = mImageRevealHelper.getReveal();
+
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        glUniform1f(mWallpaper.getHandle(ImageGLWallpaper.U_AOD2OPACITY), 1);
+        glUniform1f(mWallpaper.getHandle(ImageGLWallpaper.U_CENTER_REVEAL), threshold);
+        glUniform1f(mWallpaper.getHandle(ImageGLWallpaper.U_REVEAL), reveal);
+
+        mWallpaper.useTexture();
+        mWallpaper.draw();
+    }
+
+    @Override
+    public void onAmbientModeChanged(boolean inAmbientMode, long duration) {
+        mImageRevealHelper.updateAwake(!inAmbientMode, duration);
+        requestRender();
+    }
+
+    @Override
+    public void onOffsetsChanged(float xOffset, float yOffset, Rect frame) {
+        if (frame == null || mWallpaperManager == null
+                || (xOffset == mXOffset && yOffset == mYOffset)) {
+            return;
+        }
+
+        Bitmap bitmap = mWallpaperManager.getBitmap();
+        if (bitmap == null) {
+            return;
+        }
+
+        int width = frame.width();
+        int height = frame.height();
+        mXOffset = xOffset;
+        mYOffset = yOffset;
+
+        if (Build.IS_DEBUGGABLE) {
+            Log.d(TAG, "onOffsetsChanged: width=" + width + ", height=" + height
+                    + ", xOffset=" + mXOffset + ", yOffset=" + mYOffset);
+        }
+        mWallpaper.adjustTextureCoordinates(bitmap, width, height, mXOffset, mYOffset);
+        requestRender();
+    }
+
+    @Override
+    public void onRevealStateChanged() {
+        requestRender();
+    }
+
+    private void requestRender() {
+        if (mGLView != null) {
+            mGLView.render();
+        }
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
index 30d5b653deba..008eeefa8341 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java
@@ -479,8 +479,7 @@ public class StatusBar extends SystemUI implements DemoMode,
             updateAodMaskVisibility(deviceSupportsAodWallpaper && aodImageWallpaperEnabled);
             // If WallpaperInfo is null, it must be ImageWallpaper.
             final boolean supportsAmbientMode = deviceSupportsAodWallpaper
-                    && (info == null && aodImageWallpaperEnabled
-                        || info != null && info.supportsAmbientMode());
+                    && (info == null || info.supportsAmbientMode());
 
             mStatusBarWindowController.setWallpaperSupportsAmbientMode(supportsAmbientMode);
             mScrimController.setWallpaperSupportsAmbientMode(supportsAmbientMode);
diff --git a/packages/SystemUI/src/com/android/systemui/wallpaper/AodMaskView.java b/packages/SystemUI/src/com/android/systemui/wallpaper/AodMaskView.java
index 6ee341dd974c..f446cefb7b6f 100644
--- a/packages/SystemUI/src/com/android/systemui/wallpaper/AodMaskView.java
+++ b/packages/SystemUI/src/com/android/systemui/wallpaper/AodMaskView.java
@@ -156,6 +156,8 @@ public class AodMaskView extends ImageView implements StatusBarStateController.S
 
     private boolean checkIfNeedMask() {
         // We need mask for ImageWallpaper / LockScreen Wallpaper (Music album art).
+        // Because of conflicting with another wallpaper feature,
+        // we only support LockScreen wallpaper currently.
         return mWallpaperManager.getWallpaperInfo() == null || ScrimState.AOD.hasBackdrop();
     }
 
diff --git a/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java b/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
index b0ef8a0d4209..071dde74f103 100644
--- a/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
+++ b/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
@@ -2243,12 +2243,9 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         synchronized (mLock) {
             mInAmbientMode = inAmbientMode;
             final WallpaperData data = mWallpaperMap.get(mCurrentUserId);
-            final boolean hasConnection = data != null && data.connection != null;
-            final WallpaperInfo info = hasConnection ? data.connection.mInfo : null;
-
             // The wallpaper info is null for image wallpaper, also use the engine in this case.
-            if (hasConnection && (info == null && isAodImageWallpaperEnabled()
-                    || info != null && info.supportsAmbientMode())) {
+            if (data != null && data.connection != null && (data.connection.mInfo == null
+                    || data.connection.mInfo.supportsAmbientMode())) {
                 // TODO(multi-display) Extends this method with specific display.
                 engine = data.connection.getDisplayConnectorOrCreate(DEFAULT_DISPLAY).mEngine;
             } else {