android之图片的颜色处理

先看效果图：

图片的颜色处理的基本步骤：

1.先拿到一张原图

2.拿到一张和原图一样的纸

3.把纸固定在画板上

4.颜色的取值

5.进度条的拖动与监听

代码编写：

布局：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="青--红" />
    <SeekBar 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/red_seekbar"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="青--绿" />
    <SeekBar 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/green_seekbar"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="青--蓝" />
    <SeekBar 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/blue_seekbar"/>
    <ImageView 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/im"
        android:src="@drawable/img_small_1"/>

</LinearLayout>

activity：

public class MainActivity extends Activity implements OnSeekBarChangeListener{

	private SeekBar red_sb,green_sb,blue_sb;
	private ImageView imageView;
	private Canvas canvas;
	private Paint paint;
	private Bitmap baseBitmap,copyBitmap;
	private float red_vector,green_vector,blue_vector;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		red_sb=(SeekBar) findViewById(R.id.red_seekbar);
		green_sb=(SeekBar) findViewById(R.id.green_seekbar);
		blue_sb=(SeekBar) findViewById(R.id.blue_seekbar);
		imageView=(ImageView) findViewById(R.id.im);
		red_sb.setOnSeekBarChangeListener(this);
		green_sb.setOnSeekBarChangeListener(this);
		blue_sb.setOnSeekBarChangeListener(this);
	}


	@Override
	public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void onStartTrackingTouch(SeekBar seekBar) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void onStopTrackingTouch(SeekBar seekBar) {
		// TODO Auto-generated method stub
		int progress=seekBar.getProgress();
		float count=progress/50f;//使拖动条的取值为0f-2f,满足我们的取值要求
		switch (seekBar.getId()) {
		case R.id.red_seekbar:
			this.red_vector=count;
			
			break;
        case R.id.green_seekbar:
			this.green_vector=count;
			
			break;
        case R.id.blue_seekbar:
        	this.blue_vector=count;
        	
        	break;

		default:
			break;
		}
		//主题代码
		baseBitmap=BitmapFactory.decodeResource(getResources(), R.drawable.img_small_1);
		copyBitmap=Bitmap.createBitmap(baseBitmap.getWidth(), baseBitmap.getHeight(), baseBitmap.getConfig());
		canvas=new Canvas(copyBitmap);
		Matrix matrix=new Matrix();
		paint=new Paint();
		//vector：取值范围(0-2)
		float[] colors=new float[]{
				red_vector,0,0,0,0,
				0,green_vector,0,0,0,
				0,0,blue_vector,0,0,
				0,0,0,1,0};
		
		paint.setColorFilter(new ColorMatrixColorFilter(colors));
		canvas.drawBitmap(baseBitmap, matrix, paint);
		imageView.setImageBitmap(copyBitmap);
	}
}