android实现图片反转效果

public class ImageSurfaceView extends SurfaceView implements SurfaceHolder.Callback{
 public Bitmap image_bitmap;
 
 public ImageSurfaceView(Context context) {
 super(context);
 //添加回调
SurfaceHolder holder=this.getHolder();
 holder.addCallback(this);
 initBitmap(context);
 }
 
 public void initBitmap(Context context){ 
 Resources r=context.getResources();
 image_bitmap=BitmapFactory.decodeResource(r,R.drawable.ima);
 }
 //界面渲染
 public void onDraw(Canvas canvas){ 
 canvas.drawBitmap(image_bitmap,0,0, null); //输出第一张图片
 //初始化Matrix 该类是针对图形做一些效果的工具类
 Matrix m=new Matrix();
 m.setScale(-1,1);
 m.postTranslate(image_bitmap.getWidth()*2,0); //向右平移两个图片宽度的位置
 canvas.drawBitmap(image_bitmap, m, paint); //输出第二张图片
 }
 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width,
  int height) {
 
 }
 @Override
 public void surfaceCreated(SurfaceHolder holder) {
 Canvas canvas=holder.lockCanvas(); //调用渲染界面的方法 渲染出界面
 
 onDraw(canvas);
 holder.unlockCanvasAndPost(canvas);
 }
 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {
 // TODO Auto-generated method stub
 
 }
}