ImageUtils.java 文件源码

/**
 * 快速模糊图片
 * <p>先缩小原图，对小图进行模糊，再放大回原先尺寸</p>
 *
 * @param src 源图片
 * @param scale 缩放比例(0...1)
 * @param radius 模糊半径(0...25)
 * @param recycle 是否回收
 * @return 模糊后的图片
 */
public static Bitmap fastBlur(Bitmap src, @FloatRange(from = 0, to = 1, fromInclusive = false) float scale, @FloatRange(from = 0, to = 25, fromInclusive = false) float radius, boolean recycle) {
    if (isEmptyBitmap(src)) {
        return null;
    }
    int width = src.getWidth();
    int height = src.getHeight();
    int scaleWidth = (int) (width * scale + 0.5f);
    int scaleHeight = (int) (height * scale + 0.5f);
    if (scaleWidth == 0 || scaleHeight == 0) {
        return null;
    }
    Bitmap scaleBitmap = Bitmap
            .createScaledBitmap(src, scaleWidth, scaleHeight, true);
    Paint paint = new Paint(
            Paint.FILTER_BITMAP_FLAG | Paint.ANTI_ALIAS_FLAG);
    Canvas canvas = new Canvas();
    PorterDuffColorFilter filter = new PorterDuffColorFilter(Color.TRANSPARENT, PorterDuff.Mode.SRC_ATOP);
    paint.setColorFilter(filter);
    canvas.scale(scale, scale);
    canvas.drawBitmap(scaleBitmap, 0, 0, paint);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
        scaleBitmap = renderScriptBlur(ContextUtils
                .getContext(), scaleBitmap, radius);
    } else {
        scaleBitmap = stackBlur(scaleBitmap, (int) radius, recycle);
    }
    if (scale == 1) {
        return scaleBitmap;
    }
    Bitmap ret = Bitmap
            .createScaledBitmap(scaleBitmap, width, height, true);
    if (scaleBitmap != null && !scaleBitmap.isRecycled()) {
        scaleBitmap.recycle();
    }
    if (recycle && !src.isRecycled()) {
        src.recycle();
    }
    return ret;
}