Java实现图片倒影的源码

把做工程过程常用的一些代码段做个记录，下面代码是关于Java实现图片倒影的的代码，应该对大家有较大用处。

public class ButtonImageActivity extends Activity {
private ImageView image_btn;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
image_btn=(ImageView)findViewById(R.id.image_btn);
Bitmap bitmap =((BitmapDrawable)getResources().getDrawable(R.drawable.image_btn)).getBitmap();
image_btn.setImageBitmap(createReflectedImage(bitmap));
image_btn.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
             
        }
    });
}
private Bitmap createReflectedImage(Bitmap originalBitmap) {  
    final int reflectionGap = 4;  
       
    int width = originalBitmap.getWidth();  
    int height = originalBitmap.getHeight();  
       
    Matrix matrix = new Matrix();  
    matrix.preScale(1, -1);  
    Bitmap reflectionBitmap = Bitmap.createBitmap(originalBitmap, 0,  
            height / 2, width, height / 2, matrix, false);  
    Bitmap withReflectionBitmap = Bitmap.createBitmap(width, (height  
            + height / 2 + reflectionGap), Config.ARGB_8888);  

    Canvas canvas = new Canvas(withReflectionBitmap);  
    canvas.drawBitmap(originalBitmap, 0, 0, null);  

    Paint defaultPaint = new Paint();  
    canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);  

    canvas.drawBitmap(reflectionBitmap, 0, height + reflectionGap, null);  

    Paint paint = new Paint();  
    LinearGradient shader = new LinearGradient(0, originalBitmap.getHeight(),   
            0, withReflectionBitmap.getHeight(), 0x70ffffff, 0x00ffffff,  
            TileMode.MIRROR);  
    paint.setShader(shader);  
    paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));  

    canvas.drawRect(0, height, width, withReflectionBitmap.getHeight(), paint);  

    return withReflectionBitmap;  
}  

}