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      1 /*
      2  * Copyright (C) 2019 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 package com.android.keyguard.clock;
     17 
     18 import android.annotation.Nullable;
     19 import android.graphics.Bitmap;
     20 import android.graphics.Canvas;
     21 import android.graphics.Color;
     22 import android.os.Handler;
     23 import android.os.Looper;
     24 import android.util.Log;
     25 import android.view.View;
     26 import android.view.ViewGroup;
     27 
     28 import java.util.concurrent.Callable;
     29 import java.util.concurrent.FutureTask;
     30 
     31 /**
     32  * Creates a preview image ({@link Bitmap}) of a {@link View} for a custom clock face.
     33  */
     34 final class ViewPreviewer {
     35 
     36     private static final String TAG = "ViewPreviewer";
     37 
     38     /**
     39      * Handler used to run {@link View#draw(Canvas)} on the main thread.
     40      */
     41     private final Handler mMainHandler = new Handler(Looper.getMainLooper());
     42 
     43     /**
     44      * Generate a realistic preview of a clock face.
     45      *
     46      * @param view view is used to generate preview image.
     47      * @param width width of the preview image, should be the same as device width in pixels.
     48      * @param height height of the preview image, should be the same as device height in pixels.
     49      * @return bitmap of view.
     50      */
     51     @Nullable
     52     Bitmap createPreview(View view, int width, int height) {
     53         if (view == null) {
     54             return null;
     55         }
     56         FutureTask<Bitmap> task = new FutureTask<>(new Callable<Bitmap>() {
     57             @Override
     58             public Bitmap call() {
     59                 Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
     60 
     61                 // Draw clock view hierarchy to canvas.
     62                 Canvas canvas = new Canvas(bitmap);
     63                 canvas.drawColor(Color.BLACK);
     64                 dispatchVisibilityAggregated(view, true);
     65                 view.measure(View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY),
     66                         View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.EXACTLY));
     67                 view.layout(0, 0, width, height);
     68                 view.draw(canvas);
     69 
     70                 return bitmap;
     71             }
     72         });
     73 
     74         if (Looper.myLooper() == Looper.getMainLooper()) {
     75             task.run();
     76         } else {
     77             mMainHandler.post(task);
     78         }
     79 
     80         try {
     81             return task.get();
     82         } catch (Exception e) {
     83             Log.e(TAG, "Error completing task", e);
     84             return null;
     85         }
     86     }
     87 
     88     private void dispatchVisibilityAggregated(View view, boolean isVisible) {
     89         // Similar to View.dispatchVisibilityAggregated implementation.
     90         final boolean thisVisible = view.getVisibility() == View.VISIBLE;
     91         if (thisVisible || !isVisible) {
     92             view.onVisibilityAggregated(isVisible);
     93         }
     94 
     95         if (view instanceof ViewGroup) {
     96             isVisible = thisVisible && isVisible;
     97             ViewGroup vg = (ViewGroup) view;
     98             int count = vg.getChildCount();
     99 
    100             for (int i = 0; i < count; i++) {
    101                 dispatchVisibilityAggregated(vg.getChildAt(i), isVisible);
    102             }
    103         }
    104     }
    105 }
    106