Android Bitmap图片压缩，图片倒影

 /**
     * 图片倒影
     *
     * @param originalBitmap 原始图片
     * @return 带倒影图片
     */
    public static Bitmap createReflectedImage(Bitmap originalBitmap, boolean isAppStart) {
        int refectionGap;
        if (isAppStart) {
            refectionGap = 0;
        } else {
            refectionGap = 4;
        }
        int width = originalBitmap.getWidth();
        int height = originalBitmap.getHeight();
        Matrix matrix = new Matrix();
        matrix.preScale(1, -1);//x轴变为原来的1倍,y轴变为原来的-1倍
        Bitmap reflectionBitmap = Bitmap.createBitmap(originalBitmap, 0, height >> 1, width, height >> 1, matrix, false);
        Bitmap withReflectionBitmap = Bitmap.createBitmap(width, (height + (height >> 1) + refectionGap), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(withReflectionBitmap);
        //画原始图片
        canvas.drawBitmap(originalBitmap, 0, 0, null);
        //画间隔
        Paint defaultPaint = new Paint();
        canvas.drawRect(0, height, width, height + refectionGap, defaultPaint);
        //画倒影
        canvas.drawBitmap(reflectionBitmap, 0, height + refectionGap, null);
        //实现倒影
        Paint paint = new Paint();
        LinearGradient shader = new LinearGradient(0, originalBitmap.getHeight(), 0, withReflectionBitmap.getHeight() + 4, 0x70ffffff, 0x00ffffff, Shader.TileMode.MIRROR);
        paint.setShader(shader);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
        canvas.drawRect(0, height, width, withReflectionBitmap.getHeight(), paint);
        reflectionBitmap.recycle();
        originalBitmap.recycle();
        return withReflectionBitmap;
    }

    /**
     * 获取压缩比率
     *
     * @param options
     * @param reqWidth  目标宽度
     * @param reqHeight 目标高度
     * @return 压缩比率
     */
    private static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        int height = options.outHeight;
        int width = options.outWidth;
        int inSampleSize = 1;
        if (height > reqHeight || width > reqWidth) {
            int heightRatio = Math.round((float) height / (float) reqHeight);
            int widthRatio = Math.round((float) width / (float) reqWidth);
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }
        return inSampleSize;
    }

    /**
     * 对图片进行压缩
     *
     * @param mResources Resources
     * @param imageId    图片资源ID
     * @param reqWidth   目标宽度
     * @param reqHeight  目标高度
     * @return bitmap
     */
    public static Bitmap decodeSampleBitmapFromResource(Resources mResources, int imageId, int reqWidth, int reqHeight) {
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(mResources, imageId, options);
        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
        options.inJustDecodeBounds = false;
        return BitmapFactory.decodeResource(mResources, imageId, options);
    }