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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.view;
     18 
     19 import android.graphics.Bitmap;
     20 
     21 import java.util.ArrayList;
     22 
     23 /**
     24  * An implementation of display list for OpenGL ES 2.0.
     25  */
     26 class GLES20DisplayList extends DisplayList {
     27     // These lists ensure that any Bitmaps recorded by a DisplayList are kept alive as long
     28     // as the DisplayList is alive.  The Bitmaps are populated by the GLES20RecordingCanvas.
     29     final ArrayList<Bitmap> mBitmaps = new ArrayList<Bitmap>(5);
     30 
     31     private GLES20RecordingCanvas mCanvas;
     32     private boolean mValid;
     33 
     34     // The native display list will be destroyed when this object dies.
     35     // DO NOT overwrite this reference once it is set.
     36     private DisplayListFinalizer mFinalizer;
     37 
     38     int getNativeDisplayList() {
     39         if (!mValid || mFinalizer == null) {
     40             throw new IllegalStateException("The display list is not valid.");
     41         }
     42         return mFinalizer.mNativeDisplayList;
     43     }
     44 
     45     @Override
     46     HardwareCanvas start() {
     47         if (mCanvas != null) {
     48             throw new IllegalStateException("Recording has already started");
     49         }
     50 
     51         mValid = false;
     52         mCanvas = GLES20RecordingCanvas.obtain(this);
     53         mCanvas.start();
     54         return mCanvas;
     55     }
     56 
     57     @Override
     58     void invalidate() {
     59         if (mCanvas != null) {
     60             mCanvas.recycle();
     61             mCanvas = null;
     62         }
     63         mValid = false;
     64     }
     65 
     66     @Override
     67     boolean isValid() {
     68         return mValid;
     69     }
     70 
     71     @Override
     72     void end() {
     73         if (mCanvas != null) {
     74             if (mFinalizer != null) {
     75                 mCanvas.end(mFinalizer.mNativeDisplayList);
     76             } else {
     77                 mFinalizer = new DisplayListFinalizer(mCanvas.end(0));
     78             }
     79             mCanvas.recycle();
     80             mCanvas = null;
     81             mValid = true;
     82         }
     83     }
     84 
     85     @Override
     86     int getSize() {
     87         if (mFinalizer == null) return 0;
     88         return GLES20Canvas.getDisplayListSize(mFinalizer.mNativeDisplayList);
     89     }
     90 
     91     private static class DisplayListFinalizer {
     92         final int mNativeDisplayList;
     93 
     94         public DisplayListFinalizer(int nativeDisplayList) {
     95             mNativeDisplayList = nativeDisplayList;
     96         }
     97 
     98         @Override
     99         protected void finalize() throws Throwable {
    100             try {
    101                 GLES20Canvas.destroyDisplayList(mNativeDisplayList);
    102             } finally {
    103                 super.finalize();
    104             }
    105         }
    106     }
    107 }
    108