Avoid redundant wallpaper loading/drawing

Switching users causes wallpapers to get recreated 3 times. Other operations
like startup and rotation cause similar redundant load/draw operations. This change
tracks the various attributes that tell us when we really need to reload
and redraw, causing only one of these expensive operation per one of these
switches.

Issue #7334664 Wallpaper draws several times when switching users

Change-Id: Ic3072ef3a7eaf622d8632e87e34f50999f716c39

Author: chethaase

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

@@ -31,8 +31,10 @@
 import android.renderscript.Matrix4f;
 import android.service.wallpaper.WallpaperService;
 import android.util.Log;
+import android.view.Display;
 import android.view.MotionEvent;
 import android.view.SurfaceHolder;
+import android.view.WindowManager;
 
 import javax.microedition.khronos.egl.EGL10;
 import javax.microedition.khronos.egl.EGLConfig;
@@ -108,6 +110,7 @@ class DrawableEngine extends Engine {
 
         Bitmap mBackground;
         int mBackgroundWidth = -1, mBackgroundHeight = -1;
+        int mLastRotation = -1;
         float mXOffset;
         float mYOffset;
 
@@ -156,7 +159,7 @@ public void onReceive(Context context, Intent intent) {
                     mBackgroundWidth = mBackgroundHeight = -1;
                     mBackground = null;
                     mRedrawNeeded = true;
-                    drawFrameLocked(false);
+                    drawFrameLocked();
                 }
             }
         }
@@ -225,7 +228,7 @@ void updateSurfaceSize(SurfaceHolder surfaceHolder) {
         @Override
         public void onVisibilityChanged(boolean visible) {
             if (DEBUG) {
-                Log.d(TAG, "onVisibilityChanged: visible=" + visible);
+                Log.d(TAG, "onVisibilityChanged: mVisible, visible=" + mVisible + ", " + visible);
             }
 
             synchronized (mLock) {
@@ -234,7 +237,7 @@ public void onVisibilityChanged(boolean visible) {
                         Log.d(TAG, "Visibility changed to visible=" + visible);
                     }
                     mVisible = visible;
-                    drawFrameLocked(false);
+                    drawFrameLocked();
                 }
             }
         }
@@ -263,7 +266,7 @@ public void onOffsetsChanged(float xOffset, float yOffset,
                     mYOffset = yOffset;
                     mOffsetsChanged = true;
                 }
-                drawFrameLocked(false);
+                drawFrameLocked();
             }
         }
 
@@ -276,80 +279,81 @@ public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int he
             super.onSurfaceChanged(holder, format, width, height);
 
             synchronized (mLock) {
-                mRedrawNeeded = true;
-                mBackgroundWidth = mBackgroundHeight = -1;
-                drawFrameLocked(true);
+                drawFrameLocked();
             }
         }
 
+        @Override
+        public void onSurfaceDestroyed(SurfaceHolder holder) {
+            super.onSurfaceDestroyed(holder);
+            mBackgroundWidth = mBackgroundHeight = -1;
+        }
+
+        @Override
+        public void onSurfaceCreated(SurfaceHolder holder) {
+            super.onSurfaceCreated(holder);
+            mBackgroundWidth = mBackgroundHeight = -1;
+        }
+
         @Override
         public void onSurfaceRedrawNeeded(SurfaceHolder holder) {
             if (DEBUG) {
-                Log.d(TAG, "onSurfaceRedrawNeeded:");
+                Log.d(TAG, "onSurfaceRedrawNeeded");
             }
             super.onSurfaceRedrawNeeded(holder);
 
             synchronized (mLock) {
-                mRedrawNeeded = true;
-                drawFrameLocked(false);
+                drawFrameLocked();
             }
         }
 
-        void drawFrameLocked(boolean force) {
-            if (!force) {
-                if (!mVisible) {
-                    if (DEBUG) {
-                        Log.d(TAG, "Suppressed drawFrame since wallpaper is not visible.");
-                    }
-                    return;
-                }
-                if (!mRedrawNeeded && !mOffsetsChanged) {
-                    if (DEBUG) {
-                        Log.d(TAG, "Suppressed drawFrame since redraw is not needed "
-                                + "and offsets have not changed.");
-                    }
-                    return;
+        void drawFrameLocked() {
+            SurfaceHolder sh = getSurfaceHolder();
+            final Rect frame = sh.getSurfaceFrame();
+            final int dw = frame.width();
+            final int dh = frame.height();
+            int newRotation = ((WindowManager) getSystemService(WINDOW_SERVICE)).
+                    getDefaultDisplay().getRotation();
+
+            boolean redrawNeeded = dw != mBackgroundWidth || dh != mBackgroundHeight ||
+                    newRotation != mLastRotation;
+            if (!redrawNeeded && !mOffsetsChanged) {
+                if (DEBUG) {
+                    Log.d(TAG, "Suppressed drawFrame since redraw is not needed "
+                            + "and offsets have not changed.");
                 }
+                return;
             }
-            // If we don't yet know the size of the wallpaper bitmap,
-            // we need to get it now.
-            boolean updateWallpaper = mBackgroundWidth < 0 || mBackgroundHeight < 0 ;
-
-            // If we somehow got to this point after we have last flushed
-            // the wallpaper, well we really need it to draw again.  So
-            // seems like we need to reload it.  Ouch.
-            updateWallpaper = updateWallpaper || mBackground == null;
+            mLastRotation = newRotation;
 
-            if (updateWallpaper) {
+            // Load bitmap if it is not yet loaded or if it was loaded at a different size
+            if (mBackground == null || dw != mBackgroundWidth || dw != mBackgroundHeight) {
+                if (DEBUG) {
+                    Log.d(TAG, "Reloading bitmap");
+                }
+                mWallpaperManager.forgetLoadedWallpaper();
                 updateWallpaperLocked();
             }
 
-            SurfaceHolder sh = getSurfaceHolder();
-            final Rect frame = sh.getSurfaceFrame();
-            final int dw = frame.width();
-            final int dh = frame.height();
             final int availw = dw - mBackgroundWidth;
             final int availh = dh - mBackgroundHeight;
             int xPixels = availw < 0 ? (int)(availw * mXOffset + .5f) : (availw / 2);
             int yPixels = availh < 0 ? (int)(availh * mYOffset + .5f) : (availh / 2);
 
             mOffsetsChanged = false;
-            if (!force && !mRedrawNeeded
-                    && xPixels == mLastXTranslation && yPixels == mLastYTranslation) {
+            mRedrawNeeded = false;
+            mLastXTranslation = xPixels;
+            mLastYTranslation = yPixels;
+            if (!redrawNeeded && xPixels == mLastXTranslation && yPixels == mLastYTranslation) {
                 if (DEBUG) {
                     Log.d(TAG, "Suppressed drawFrame since the image has not "
                             + "actually moved an integral number of pixels.");
                 }
                 return;
             }
-            mRedrawNeeded = false;
-            mLastXTranslation = xPixels;
-            mLastYTranslation = yPixels;
 
             if (DEBUG) {
-                Log.d(TAG, "drawFrameUnlocked(" + force + "): mBackgroundWxH=" + mBackgroundWidth + "x"
-                        + mBackgroundHeight + " SurfaceFrame=" + frame.toShortString()
-                        + " X,YOffset=" + mXOffset + "," + mYOffset);
+                Log.d(TAG, "Redrawing wallpaper");
             }
             if (mIsHwAccelerated) {
                 if (!drawWallpaperWithOpenGL(sh, availw, availh, xPixels, yPixels)) {
@@ -429,15 +433,14 @@ private boolean drawWallpaperWithOpenGL(SurfaceHolder sh, int w, int h, int left
             final float bottom = top + mBackgroundHeight;
 
             final Rect frame = sh.getSurfaceFrame();
-
             final Matrix4f ortho = new Matrix4f();
             ortho.loadOrtho(0.0f, frame.width(), frame.height(), 0.0f, -1.0f, 1.0f);
 
             final FloatBuffer triangleVertices = createMesh(left, top, right, bottom);
 
             final int texture = loadTexture(mBackground);
             final int program = buildProgram(sSimpleVS, sSimpleFS);
-    
+
             final int attribPosition = glGetAttribLocation(program, "position");
             final int attribTexCoords = glGetAttribLocation(program, "texCoords");
             final int uniformTexture = glGetUniformLocation(program, "texture");
@@ -460,7 +463,7 @@ private boolean drawWallpaperWithOpenGL(SurfaceHolder sh, int w, int h, int left
                 glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
                 glClear(GL_COLOR_BUFFER_BIT);
             }
-    
+
             // drawQuad
             triangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET);
             glVertexAttribPointer(attribPosition, 3, GL_FLOAT, false,
@@ -471,12 +474,12 @@ private boolean drawWallpaperWithOpenGL(SurfaceHolder sh, int w, int h, int left
                     TRIANGLE_VERTICES_DATA_STRIDE_BYTES, triangleVertices);
 
             glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
-    
+
             if (!mEgl.eglSwapBuffers(mEglDisplay, mEglSurface)) {
                 throw new RuntimeException("Cannot swap buffers");
             }
             checkEglError();
-    
+
             finishGL();
 
             return true;