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
17package com.example.android.apis.graphics;
18
19import android.content.Context;
20import android.graphics.*;
21import android.os.Bundle;
22import android.view.View;
23
24public class Regions 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 final Paint mPaint = new Paint();
34        private final Rect  mRect1 = new Rect();
35        private final Rect  mRect2 = new Rect();
36
37        public SampleView(Context context) {
38            super(context);
39            setFocusable(true);
40
41            mPaint.setAntiAlias(true);
42            mPaint.setTextSize(16);
43            mPaint.setTextAlign(Paint.Align.CENTER);
44
45            mRect1.set(10, 10, 100, 80);
46            mRect2.set(50, 50, 130, 110);
47        }
48
49        private void drawOriginalRects(Canvas canvas, int alpha) {
50            mPaint.setStyle(Paint.Style.STROKE);
51            mPaint.setColor(Color.RED);
52            mPaint.setAlpha(alpha);
53            drawCentered(canvas, mRect1, mPaint);
54            mPaint.setColor(Color.BLUE);
55            mPaint.setAlpha(alpha);
56            drawCentered(canvas, mRect2, mPaint);
57
58            // restore style
59            mPaint.setStyle(Paint.Style.FILL);
60        }
61
62        private void drawRgn(Canvas canvas, int color, String str, Region.Op op) {
63            if (str != null) {
64                mPaint.setColor(Color.BLACK);
65                canvas.drawText(str, 80, 24, mPaint);
66            }
67
68            Region rgn = new Region();
69            rgn.set(mRect1);
70            rgn.op(mRect2, op);
71
72            mPaint.setColor(color);
73            RegionIterator iter = new RegionIterator(rgn);
74            Rect r = new Rect();
75
76            canvas.translate(0, 30);
77            mPaint.setColor(color);
78            while (iter.next(r)) {
79                canvas.drawRect(r, mPaint);
80            }
81            drawOriginalRects(canvas, 0x80);
82        }
83
84        private static void drawCentered(Canvas c, Rect r, Paint p) {
85            float inset = p.getStrokeWidth() * 0.5f;
86            if (inset == 0) {   // catch hairlines
87                inset = 0.5f;
88            }
89            c.drawRect(r.left + inset, r.top + inset,
90                       r.right - inset, r.bottom - inset, p);
91        }
92
93        @Override
94        protected void onDraw(Canvas canvas) {
95            canvas.drawColor(Color.GRAY);
96
97            canvas.save();
98            canvas.translate(80, 5);
99            drawOriginalRects(canvas, 0xFF);
100            canvas.restore();
101
102            mPaint.setStyle(Paint.Style.FILL);
103
104            canvas.save();
105            canvas.translate(0, 140);
106            drawRgn(canvas, Color.RED, "Union", Region.Op.UNION);
107            canvas.restore();
108
109            canvas.save();
110            canvas.translate(0, 280);
111            drawRgn(canvas, Color.BLUE, "Xor", Region.Op.XOR);
112            canvas.restore();
113
114            canvas.save();
115            canvas.translate(160, 140);
116            drawRgn(canvas, Color.GREEN, "Difference", Region.Op.DIFFERENCE);
117            canvas.restore();
118
119            canvas.save();
120            canvas.translate(160, 280);
121            drawRgn(canvas, Color.WHITE, "Intersect", Region.Op.INTERSECT);
122            canvas.restore();
123        }
124    }
125}
126
127