1 /*
2  * Copyright (C) 2009 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.graphics.cts;
18 
19 
20 import android.graphics.Bitmap;
21 import android.graphics.Canvas;
22 import android.graphics.Color;
23 import android.graphics.DiscretePathEffect;
24 import android.graphics.Paint;
25 import android.graphics.Path;
26 import android.graphics.PorterDuffXfermode;
27 import android.graphics.Bitmap.Config;
28 import android.graphics.Paint.Style;
29 import android.graphics.PorterDuff.Mode;
30 
31 import junit.framework.TestCase;
32 
33 public class DiscretePathEffectTest extends TestCase {
34     private static final int BITMAP_WIDTH = 200;
35     private static final int BITMAP_HEIGHT = 100;
36     private static final int START_X = 10;
37     private static final int END_X = BITMAP_WIDTH - START_X;
38     private static final int COORD_Y = BITMAP_HEIGHT / 2;
39     private static final int SEGMENT_LENGTH = 10; // must be < BITMAP_WIDTH
40     private static final int DEVIATION = 10; // must be < BITMAP_HEIGHT
41 
testDiscretePathEffect()42     public void testDiscretePathEffect() {
43         DiscretePathEffect effect = new DiscretePathEffect(SEGMENT_LENGTH, DEVIATION);
44 
45         Paint paint = new Paint();
46         paint.setColor(Color.GREEN);
47         paint.setStyle(Style.STROKE);
48         paint.setStrokeWidth(0);
49         paint.setPathEffect(effect);
50 
51         Path path = new Path();
52         path.moveTo(START_X, COORD_Y);
53         path.lineTo(END_X, COORD_Y);
54 
55         Bitmap bitmap = Bitmap.createBitmap(BITMAP_WIDTH, BITMAP_HEIGHT, Config.ARGB_8888);
56         bitmap.eraseColor(Color.TRANSPARENT);
57 
58         Canvas canvas = new Canvas(bitmap);
59         canvas.drawPath(path, paint);
60 
61         // draw guide line into red channel (each segment should cross this once)
62         paint = new Paint();
63         paint.setColor(Color.RED);
64         paint.setStyle(Style.STROKE);
65         paint.setStrokeWidth(0);
66         paint.setXfermode(new PorterDuffXfermode(Mode.SCREEN));
67         canvas.drawPath(path, paint);
68 
69         // draw guide rectangle into blue channel (each segment must be completely inside this)
70         paint.setColor(Color.BLUE);
71         paint.setStrokeWidth(1 + 2 * DEVIATION);
72         canvas.drawPath(path, paint);
73 
74         int intersect = 0;
75         int numGreenPixels = 0;
76         int minY = BITMAP_HEIGHT;
77         int maxY = 0;
78         for (int y = 0; y < BITMAP_HEIGHT; y++) {
79             for (int x = 0; x < BITMAP_WIDTH; x++) {
80                 int pixel = bitmap.getPixel(x, y);
81                 if (Color.green(pixel) > 0) {
82                     numGreenPixels += 1;
83                     minY = Math.min(minY, y);
84                     maxY = Math.max(maxY, y);
85                     assertEquals(0xFF, Color.blue(pixel));
86                     if (Color.red(pixel) > 0) {
87                         intersect += 1;
88                     }
89                 }
90             }
91         }
92         int lineLength = END_X - START_X;
93         // the number of pixels in all segments must be at least the same as the line length
94         assertTrue(numGreenPixels >= lineLength);
95         // green line must vary in y direction
96         assertTrue(maxY - minY > 0);
97         // ... but not too much
98         assertTrue(maxY - minY <= 1 + 2 * DEVIATION);
99         // intersecting pixels must be less than line length, otherwise deviation doesn't work
100         assertTrue(intersect < lineLength);
101         // there must be at least as many intersecting pixels as there are full segments
102         assertTrue(intersect >= lineLength / SEGMENT_LENGTH);
103     }
104 }
105