Android-将RGB彩色图转换为灰度图

Android-将RGB彩色图转换为灰度图

实例：RGB2Grey

项目运行效果图：

源代码：

public class MainActivity extends Activity {

    /* (non-Javadoc)
     * @see android.app.Activity#onCreate(android.os.Bundle)
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //通过Id来获取界面中组件的引用
        Button rgb2greyBtn  = (Button) findViewById(R.id.rgb2greybtn);
        ImageView imageView1 = (ImageView) findViewById(R.id.imageView1);
        final ImageView imageView2 = (ImageView) findViewById(R.id.imageView2); 
        //通过位图工厂，创建一个位图
        final Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_android);
        imageView1.setImageBitmap(bitmap);
        //为“转换为灰度图”按钮添加监听事件
        rgb2greyBtn.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				//将转换过后的灰度图显示出来
				imageView2.setImageBitmap(convertGreyImg(bitmap));
			}
		});
        
    }
    
    /**
     * 将彩色图转换为灰度图
     * @param img 位图
     * @return	返回转换好的位图
     */
    public Bitmap convertGreyImg(Bitmap img) {
    	int width = img.getWidth();			//获取位图的宽
    	int height = img.getHeight();		//获取位图的高
    	
    	int []pixels = new int[width * height];	//通过位图的大小创建像素点数组
    	
    	img.getPixels(pixels, 0, width, 0, 0, width, height);
    	int alpha = 0xFF << 24; 
    	for(int i = 0; i < height; i++)	{
    		for(int j = 0; j < width; j++) {
    			int grey = pixels[width * i + j];
    			
    			int red = ((grey  & 0x00FF0000 ) >> 16);
    			int green = ((grey & 0x0000FF00) >> 8);
    			int blue = (grey & 0x000000FF);
    			
    			grey = (int)((float) red * 0.3 + (float)green * 0.59 + (float)blue * 0.11);
    			grey = alpha | (grey << 16) | (grey << 8) | grey;
    			pixels[width * i + j] = grey;
    		}
    	}
    	Bitmap result = Bitmap.createBitmap(width, height, Config.RGB_565);
    	result.setPixels(pixels, 0, width, 0, 0, width, height);
    	return result;
    }
}

布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/LinearLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
	<ImageView 
	    android:id="@+id/imageView1"
	    android:layout_width="wrap_content"
	    android:layout_height="wrap_content"
	    android:layout_gravity="center_horizontal"
	    />
	<Button 
	    android:id="@+id/rgb2greybtn"
	    android:layout_width="wrap_content"
	    android:layout_height="wrap_content"
	    android:text="@string/rgb2greybtn"
	    android:layout_gravity="center_horizontal"/>
	<ImageView 
	    android:id="@+id/imageView2"
	    android:layout_width="wrap_content"
	    android:layout_height="wrap_content"
	    android:layout_gravity="center_horizontal"
	    />"
</LinearLayout>