Move image wallpaper rendering works to background thread.

Doing image wallpaper rendering works on main thread may cause other
animation in system ui janky, so move the drawing task of image
wallpaper to another thread. We also make draw low priority.

Bug: 135601062
Test: observe log and systrace
Change-Id: I7bda6a757cb63f97f6b03c4b035fedbf87f91c96

packages/SystemUI/src/com/android/systemui/ImageWallpaper.java

@@ -19,6 +19,7 @@ package com.android.systemui;
 import android.app.ActivityManager;
 import android.content.Context;
 import android.graphics.Rect;
+import android.os.HandlerThread;
 import android.service.wallpaper.WallpaperService;
 import android.util.Log;
 import android.util.Size;
@@ -45,12 +46,27 @@ public class ImageWallpaper extends WallpaperService {
     // We delayed destroy render context that subsequent render requests have chance to cancel it.
     // This is to avoid destroying then recreating render context in a very short time.
     private static final int DELAY_FINISH_RENDERING = 1000;
+    private HandlerThread mWorker;
+
+    @Override
+    public void onCreate() {
+        super.onCreate();
+        mWorker = new HandlerThread(TAG);
+        mWorker.start();
+    }
 
     @Override
     public Engine onCreateEngine() {
         return new GLEngine(this);
     }
 
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        mWorker.quitSafely();
+        mWorker = null;
+    }
+
     class GLEngine extends Engine implements GLWallpaperRenderer.SurfaceProxy, StateListener {
         // Surface is rejected if size below a threshold on some devices (ie. 8px on elfin)
         // set min to 64 px (CTS covers this), please refer to ag/4867989 for detail.
@@ -98,13 +114,14 @@ public class ImageWallpaper extends WallpaperService {
         @Override
         public void onOffsetsChanged(float xOffset, float yOffset, float xOffsetStep,
                 float yOffsetStep, int xPixelOffset, int yPixelOffset) {
-            mRenderer.updateOffsets(xOffset, yOffset);
+            mWorker.getThreadHandler().post(() -> mRenderer.updateOffsets(xOffset, yOffset));
         }
 
         @Override
         public void onAmbientModeChanged(boolean inAmbientMode, long animationDuration) {
-            mRenderer.updateAmbientMode(inAmbientMode,
-                    (mNeedTransition || animationDuration != 0) ? animationDuration : 0);
+            long duration = mNeedTransition || animationDuration != 0 ? animationDuration : 0;
+            mWorker.getThreadHandler().post(
+                    () -> mRenderer.updateAmbientMode(inAmbientMode, duration));
         }
 
         @Override
@@ -113,53 +130,61 @@ public class ImageWallpaper extends WallpaperService {
                 mController.removeCallback(this /* StateListener */);
             }
             mController = null;
-            mRenderer.finish();
-            mRenderer = null;
-            mEglHelper.finish();
-            mEglHelper = null;
-            getSurfaceHolder().getSurface().hwuiDestroy();
+
+            mWorker.getThreadHandler().post(() -> {
+                mRenderer.finish();
+                mRenderer = null;
+                mEglHelper.finish();
+                mEglHelper = null;
+                getSurfaceHolder().getSurface().hwuiDestroy();
+            });
         }
 
         @Override
         public void onSurfaceCreated(SurfaceHolder holder) {
-            mEglHelper.init(holder);
-            mRenderer.onSurfaceCreated();
+            mWorker.getThreadHandler().post(() -> {
+                mEglHelper.init(holder);
+                mRenderer.onSurfaceCreated();
+            });
         }
 
         @Override
         public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int height) {
-            mRenderer.onSurfaceChanged(width, height);
-            mNeedRedraw = true;
+            mWorker.getThreadHandler().post(() -> {
+                mRenderer.onSurfaceChanged(width, height);
+                mNeedRedraw = true;
+            });
         }
 
         @Override
         public void onSurfaceRedrawNeeded(SurfaceHolder holder) {
-            if (mNeedRedraw) {
-                preRender();
-                requestRender();
-                postRender();
-                mNeedRedraw = false;
-            }
-        }
-
-        @Override
-        public SurfaceHolder getHolder() {
-            return getSurfaceHolder();
+            mWorker.getThreadHandler().post(() -> {
+                if (mNeedRedraw) {
+                    preRender();
+                    requestRender();
+                    postRender();
+                    mNeedRedraw = false;
+                }
+            });
         }
 
         @Override
         public void onStatePostChange() {
             // When back to home, we try to release EGL, which is preserved in lock screen or aod.
             if (mController.getState() == StatusBarState.SHADE) {
-                scheduleFinishRendering();
+                mWorker.getThreadHandler().post(this::scheduleFinishRendering);
             }
         }
 
         @Override
         public void preRender() {
+            mWorker.getThreadHandler().post(this::preRenderInternal);
+        }
+
+        private void preRenderInternal() {
             boolean contextRecreated = false;
             Rect frame = getSurfaceHolder().getSurfaceFrame();
-            getMainThreadHandler().removeCallbacks(mFinishRenderingTask);
+            cancelFinishRenderingTask();
 
             // Check if we need to recreate egl context.
             if (!mEglHelper.hasEglContext()) {
@@ -187,6 +212,10 @@ public class ImageWallpaper extends WallpaperService {
 
         @Override
         public void requestRender() {
+            mWorker.getThreadHandler().post(this::requestRenderInternal);
+        }
+
+        private void requestRenderInternal() {
             Rect frame = getSurfaceHolder().getSurfaceFrame();
             boolean readyToRender = mEglHelper.hasEglContext() && mEglHelper.hasEglSurface()
                     && frame.width() > 0 && frame.height() > 0;
@@ -205,12 +234,16 @@ public class ImageWallpaper extends WallpaperService {
 
         @Override
         public void postRender() {
-            scheduleFinishRendering();
+            mWorker.getThreadHandler().post(this::scheduleFinishRendering);
+        }
+
+        private void cancelFinishRenderingTask() {
+            mWorker.getThreadHandler().removeCallbacks(mFinishRenderingTask);
         }
 
         private void scheduleFinishRendering() {
-            getMainThreadHandler().removeCallbacks(mFinishRenderingTask);
-            getMainThreadHandler().postDelayed(mFinishRenderingTask, DELAY_FINISH_RENDERING);
+            cancelFinishRenderingTask();
+            mWorker.getThreadHandler().postDelayed(mFinishRenderingTask, DELAY_FINISH_RENDERING);
         }
 
         private void finishRendering() {

packages/SystemUI/src/com/android/systemui/glwallpaper/EglHelper.java

@@ -60,6 +60,9 @@ import java.io.PrintWriter;
  */
 public class EglHelper {
     private static final String TAG = EglHelper.class.getSimpleName();
+    // Below two constants make drawing at low priority, so other things can preempt our drawing.
+    private static final int EGL_CONTEXT_PRIORITY_LEVEL_IMG = 0x3100;
+    private static final int EGL_CONTEXT_PRIORITY_LOW_IMG = 0x3103;
 
     private EGLDisplay mEglDisplay;
     private EGLConfig mEglConfig;
@@ -181,7 +184,8 @@ public class EglHelper {
      * @return true if EglContext is ready.
      */
     public boolean createEglContext() {
-        int[] attrib_list = new int[] {EGL_CONTEXT_CLIENT_VERSION, 2, EGL_NONE};
+        int[] attrib_list = new int[] {EGL_CONTEXT_CLIENT_VERSION, 2,
+                EGL_CONTEXT_PRIORITY_LEVEL_IMG, EGL_CONTEXT_PRIORITY_LOW_IMG, EGL_NONE};
         mEglContext = eglCreateContext(mEglDisplay, mEglConfig, EGL_NO_CONTEXT, attrib_list, 0);
         if (mEglContext == EGL_NO_CONTEXT) {
             Log.w(TAG, "eglCreateContext failed: " + GLUtils.getEGLErrorString(eglGetError()));

packages/SystemUI/src/com/android/systemui/glwallpaper/GLWallpaperRenderer.java

@@ -17,7 +17,6 @@
 package com.android.systemui.glwallpaper;
 
 import android.util.Size;
-import android.view.SurfaceHolder;
 
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
@@ -82,12 +81,6 @@ public interface GLWallpaperRenderer {
      */
     interface SurfaceProxy {
 
-        /**
-         * Get surface holder.
-         * @return surface holder.
-         */
-        SurfaceHolder getHolder();
-
         /**
          * Ask proxy to start rendering frame to surface.
          */