Android 图片翻转技术实现

public  Bitmap createBitmapForWatermark(Bitmap src, Bitmap watermark) {
        if (src == null) {
            return null;
        }
        int w = src.getWidth();
        int h = src.getHeight();
        int ww = watermark.getWidth();
        int wh = watermark.getHeight();
        Bitmap newb = Bitmap.createBitmap(ww, wh, Config.ARGB_8888);// 创建一个新的和SRC长度宽度一样的位图
        Canvas cv = new Canvas(newb);
        
        Matrix m = new Matrix();
        m.postScale(1, -1);//上下翻转
        m.postRotate(-90);//左右翻转
        Bitmap newBitmap = Bitmap.createBitmap(src, 0, 0, w, h, m, true);
        cv.drawBitmap(newBitmap, new Rect(0, 0, newBitmap.getWidth(), newBitmap.getHeight()),new Rect(0, 0, ww, wh), null);
        
        cv.drawBitmap(watermark,0,0, null);// 前景图或水印
        
        cv.save(Canvas.ALL_SAVE_FLAG);// 保存
        // store
        cv.restore();// 存储
        return newb;
    }


下面的方法则是用像素处理，速度会慢一点。

    Bitmap changePixel_180(Bitmap orgBitmap) {
        int pixels_width;