Android（java）学习笔记240：多媒体之图形颜色的变化

1.相信大家都用过美图秀秀中如下的功能，调整颜色：

2. 下面通过案例说明Android中如何调色：

颜色矩阵 ColorMatrix cm = new ColorMatrix();

paint.setColorFilter(new ColorMatrixColorFilter(cm));

1 0 0 0 0

0 1 0 0 0

0 0 1 0 0

0 0 0 1 0

New Red Value = 1*128 + 0*128 + 0*128 + 0*0 + 0

New Blue Value = 0*128 + 1*128 + 0*128 + 0*0 + 0

New Green Value = 0*128 + 0*128 + 1*128 + 0*0 + 0

New Alpha Value = 0*128 + 0*128 + 0*128 + 1*0 + 0

（1）新建一个新的Android工程，如下：

（2）activity_main.xml，如下：

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical"
 6     tools:context="com.himi.xiuxiu.MainActivity" >
 7
 8     <TextView
 9         android:layout_width="wrap_content"
10         android:layout_height="wrap_content"
11         android:text="青------------->红" />
12
13     <SeekBar
14         android:id="@+id/sb_red"
15         android:max="255"
16         android:progress="128"
17         android:layout_width="match_parent"
18         android:layout_height="wrap_content" />
19      <TextView
20         android:layout_width="wrap_content"
21         android:layout_height="wrap_content"
22         android:text="紫------------->绿" />
23
24     <SeekBar
25         android:max="255"
26         android:progress="128"
27         android:id="@+id/sb_green"
28         android:layout_width="match_parent"
29         android:layout_height="wrap_content" />
30      <TextView
31         android:layout_width="wrap_content"
32         android:layout_height="wrap_content"
33         android:text="黄------------->蓝" />
34
35     <SeekBar
36         android:max="255"
37         android:progress="128"
38         android:id="@+id/sb_blue"
39         android:layout_width="match_parent"
40         android:layout_height="wrap_content" />
41     <ImageView
42         android:layout_width="wrap_content"
43         android:layout_height="wrap_content"
44         android:id="@+id/iv"
45         />
46
47 </LinearLayout>

布局效果如下：

（3）MainActivity，如下：

 1 package com.himi.xiuxiu;
 2
 3 import android.app.Activity;
 4 import android.graphics.Bitmap;
 5 import android.graphics.BitmapFactory;
 6 import android.graphics.Canvas;
 7 import android.graphics.ColorMatrix;
 8 import android.graphics.ColorMatrixColorFilter;
 9 import android.graphics.Matrix;
10 import android.graphics.Paint;
11 import android.os.Bundle;
12 import android.widget.ImageView;
13 import android.widget.SeekBar;
14 import android.widget.SeekBar.OnSeekBarChangeListener;
15
16 public class MainActivity extends Activity implements OnSeekBarChangeListener {
17     private SeekBar sb_red;
18     private SeekBar sb_green;
19     private SeekBar sb_blue;
20     private ImageView iv;
21
22     private Bitmap srcbitmap;
23     private Bitmap alertbitmap;
24     private Canvas canvas;
25     private Paint paint;
26     @Override
27     protected void onCreate(Bundle savedInstanceState) {
28         super.onCreate(savedInstanceState);
29         setContentView(R.layout.activity_main);
30         sb_red = (SeekBar) findViewById(R.id.sb_red);
31         sb_green = (SeekBar) findViewById(R.id.sb_green);
32         sb_blue = (SeekBar) findViewById(R.id.sb_blue);
33         iv = (ImageView) findViewById(R.id.iv);
34         //获得原图的位图
35         srcbitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pre19);
36         //获得原图的拷贝副本
37         alertbitmap = Bitmap.createBitmap(srcbitmap.getWidth(), srcbitmap.getHeight(), srcbitmap.getConfig());
38         //创建一个画布
39         canvas = new Canvas(alertbitmap);
40         //创建画笔
41         paint = new Paint();
42
43         ColorMatrix cm = new ColorMatrix();
44         cm.set(new float[] {
45         1, 0, 0, 0, 0,
46         0, 1, 0, 0, 0,
47         0, 0, 1, 0, 0,
48         0, 0, 0, 1, 0
49         });
50
51         paint.setColorFilter(new ColorMatrixColorFilter(cm));
52         canvas.drawBitmap(srcbitmap, new Matrix(), paint);
53         iv.setImageBitmap(alertbitmap);
54
55         sb_red.setOnSeekBarChangeListener(this);
56         sb_green.setOnSeekBarChangeListener(this);
57         sb_blue.setOnSeekBarChangeListener(this);
58
59     }
60     public void onProgressChanged(SeekBar seekBar, int progress,
61             boolean fromUser) {
62         // TODO 自动生成的方法存根
63
64     }
65     public void onStartTrackingTouch(SeekBar seekBar) {
66         // TODO 自动生成的方法存根
67
68     }
69     // 停止滑动进度条，才设置颜色变化，节省内存
70     public void onStopTrackingTouch(SeekBar seekBar) {
71         float red=1;
72         float green=1;
73         float blue=1;
74         switch (seekBar.getId()) {
75         case R.id.sb_red:
76             red = seekBar.getProgress()/128.0f;
77             break;
78         case R.id.sb_green:
79             green = seekBar.getProgress()/128.0f;
80             break;
81         case R.id.sb_blue:
82             blue = seekBar.getProgress()/128.0f;
83             break;
84
85         default:
86             break;
87         }
88         ColorMatrix cm = new ColorMatrix();
89         cm.set(new float[] {    red, 0, 0, 0, 0,
90                                 0, green, 0, 0, 0,
91                                 0, 0, blue, 0, 0,
92                                 0, 0, 0, 1, 0 });
93
94         paint.setColorFilter(new ColorMatrixColorFilter(cm));
95         canvas.drawBitmap(srcbitmap, new Matrix(), paint);
96         iv.setImageBitmap(alertbitmap);
97     }
98
99 }

运行结果如下：