Bitmap的简单特效处理

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

//这个对象是只读的
Bitmap bmSrc = BitmapFactory.decodeFile("sdcard/photo3.jpg");

//创建图片副本
//1.在内存中创建一个与原图一模一样大小的bitmap对象，创建与原图大小一致的白纸
Bitmap bmCopy = Bitmap.createBitmap(bmSrc.getWidth(), bmSrc.getHeight(), bmSrc.getConfig());

//2.创建画笔对象
Paint paint = new Paint();

//3.创建画板对象，把白纸铺在画板上
Canvas canvas = new Canvas(bmCopy);

//4.开始作画，把原图的内容绘制在白纸上
Matrix mt = new Matrix();

//平移
//        mt.setTranslate(20, 40);
//缩放
//sx：水平方向的缩放比例
//sy：竖直方向的缩放比例
//        mt.setScale(0.5f, 0.5f);
//        mt.setScale(0.5f, 0.5f, bmCopy.getWidth() / 2, bmCopy.getHeight() / 2);
//旋转
//        mt.setRotate(45, bmCopy.getWidth() / 2, bmCopy.getHeight() / 2);

//镜面
//        mt.setScale(-1, 1);
//        mt.postTranslate(bmCopy.getWidth(), 0);
//倒影
mt.setScale(1, -1);
mt.postTranslate(0, bmCopy.getHeight());
canvas.drawBitmap(bmSrc, mt, paint);

ImageView iv_src = (ImageView) findViewById(R.id.iv_src);
ImageView iv_copy = (ImageView) findViewById(R.id.iv_copy);
iv_src.setImageBitmap(bmSrc);
iv_copy.setImageBitmap(bmCopy);
}

}