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      1 /*
      2  * Copyright (C) 2008 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 com.example.android.apis.graphics;
     18 
     19 import android.content.Context;
     20 import android.graphics.*;
     21 import android.os.Bundle;
     22 import android.view.View;
     23 
     24 public class Clipping extends GraphicsActivity {
     25 
     26     @Override
     27     protected void onCreate(Bundle savedInstanceState) {
     28         super.onCreate(savedInstanceState);
     29         setContentView(new SampleView(this));
     30     }
     31 
     32     private static class SampleView extends View {
     33         private Paint mPaint;
     34         private Path mPath;
     35 
     36         public SampleView(Context context) {
     37             super(context);
     38             setFocusable(true);
     39 
     40             mPaint = new Paint();
     41             mPaint.setAntiAlias(true);
     42             mPaint.setStrokeWidth(6);
     43             mPaint.setTextSize(16);
     44             mPaint.setTextAlign(Paint.Align.RIGHT);
     45 
     46             mPath = new Path();
     47         }
     48 
     49         private void drawScene(Canvas canvas) {
     50             canvas.clipRect(0, 0, 100, 100);
     51 
     52             canvas.drawColor(Color.WHITE);
     53 
     54             mPaint.setColor(Color.RED);
     55             canvas.drawLine(0, 0, 100, 100, mPaint);
     56 
     57             mPaint.setColor(Color.GREEN);
     58             canvas.drawCircle(30, 70, 30, mPaint);
     59 
     60             mPaint.setColor(Color.BLUE);
     61             canvas.drawText("Clipping", 100, 30, mPaint);
     62         }
     63 
     64         @Override protected void onDraw(Canvas canvas) {
     65             canvas.drawColor(Color.GRAY);
     66 
     67             canvas.save();
     68             canvas.translate(10, 10);
     69             drawScene(canvas);
     70             canvas.restore();
     71 
     72             canvas.save();
     73             canvas.translate(160, 10);
     74             canvas.clipRect(10, 10, 90, 90);
     75             canvas.clipRect(30, 30, 70, 70, Region.Op.DIFFERENCE);
     76             drawScene(canvas);
     77             canvas.restore();
     78 
     79             canvas.save();
     80             canvas.translate(10, 160);
     81             mPath.reset();
     82             canvas.clipPath(mPath); // makes the clip empty
     83             mPath.addCircle(50, 50, 50, Path.Direction.CCW);
     84             canvas.clipPath(mPath);
     85             drawScene(canvas);
     86             canvas.restore();
     87         }
     88     }
     89 }
     90 
     91