先上代码：https://github.com/chenglin198751/BaseMyProject/blob/master/app/src/main/java/utils/FastBlurUtil.java
如果下面的代码有找不到的方法，那么可以去这么项目里找，完整的项目地址是：https://github.com/chenglin198751/BaseMyProject
Java已经有人很好的实现了高斯模糊，但是如果图比较大，那速度就很慢。甚至会OOM 。那么能不能快速的实现高斯模糊呢？我想了想，自己改造了一下。原理就是先压缩图片，然后再去执行高斯模糊算法。因为高斯模糊本身已经是模糊的了，原图再清晰也没啥用，所以倒不如把图片压小一点再去高斯模糊，肉眼看效果上和原图没什么大的区别，但是速度快了很多很多。具体用法见代码里面的注释。其中参数scale 和 radius ，你可以多试验几次，就能找到适合自己的参数。
看我改造后的代码，传入的参数是View ，我会自动把View 保存为Bitmap：
public class FastBlurUtil {
/**
* @param view 要被高斯模糊的View 生成的图片
* @param scale 对原图的缩放比例：从0.1到1取值，值越小速度越快，值越大速度越慢。大图建议值0.1~0.2，小图建议值0.2~0.4
* @param radius 高斯模糊的程度：从1到100取值。值越小越清晰(速度快)，越大越模糊(速度慢)，建议值10~20
* @return
*/
public static void doBlur(final View view, final float scale, final int radius, final OnFinishListener listener) {
final Bitmap sentBitmap = MyUtils.createBitmapByView(view);
new Thread() {
@Override
public void run() {
super.run();
final Bitmap bitmap = doBlur(sentBitmap, scale, radius);
MyUtils.getHandler().post(new Runnable() {
@Override
public void run() {
if (listener != null) {
listener.onFinish(bitmap);
}
}
});
}
}.start();
}
private static Bitmap doBlur(Bitmap sentBitmap, float scale, final int radius) {
// final boolean canReuseInBitmap = false;
if (scale <= 0 || scale > 1) {
scale = 1;
}
float scaledWidth = sentBitmap.getWidth() * scale;
float scaledHeight = sentBitmap.getHeight() * scaledWidth / sentBitmap.getWidth();
Bitmap bitmap = Bitmap.createScaledBitmap(sentBitmap, (int) scaledWidth, (int) scaledHeight, true);
// Bitmap bitmap;
// if (canReuseInBitmap) {
// bitmap = sentBitmap;
// } else {
// bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
// }
if (radius < 1) {
return (null);
}
int w = bitmap.getWidth();
int h = bitmap.getHeight();
int[] pix = new int[w * h];
bitmap.getPixels(pix, 0, w, 0, 0, w, h);
int wm = w - 1;
int hm = h - 1;
int wh = w * h;
int div = radius + radius + 1;
int r[] = new int[wh];
int g[] = new int[wh];
int b[] = new int[wh];
int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
int vmin[] = new int[Math.max(w, h)];
int divsum = (div + 1) >> 1;
divsum *= divsum;
int dv[] = new int[256 * divsum];
for (i = 0; i < 256 * divsum; i++) {
dv[i] = (i / divsum);
}
yw = yi = 0;
int[][] stack = new int[div][3];
int stackpointer;
int stackstart;
int[] sir;
int rbs;
int r1 = radius + 1;
int routsum, goutsum, boutsum;
int rinsum, ginsum, binsum;
for (y = 0; y < h; y++) {
rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
for (i = -radius; i <= radius; i++) {
p = pix[yi + Math.min(wm, Math.max(i, 0))];
sir = stack[i + radius];
sir[0] = (p & 0xff0000) >> 16;
sir[1] = (p & 0x00ff00) >> 8;
sir[2] = (p & 0x0000ff);
rbs = r1 - Math.abs(i);
rsum += sir[0] * rbs;
gsum += sir[1] * rbs;
bsum += sir[2] * rbs;
if (i > 0) {
rinsum += sir[0];
ginsum += sir[1];
binsum += sir[2];
} else {
routsum += sir[0];
goutsum += sir[1];
boutsum += sir[2];
}
}
stackpointer = radius;
for (x = 0; x < w; x++) {
r[yi] = dv[rsum];
g[yi] = dv[gsum];
b[yi] = dv[bsum];
rsum -= routsum;
gsum -= goutsum;
bsum -= boutsum;
stackstart = stackpointer - radius + div;
sir = stack[stackstart % div];
routsum -= sir[0];
goutsum -= sir[1];
boutsum -= sir[2];
if (y == 0) {
vmin[x] = Math.min(x + radius + 1, wm);
}
p = pix[yw + vmin[x]];
sir[0] = (p & 0xff0000) >> 16;
sir[1] = (p & 0x00ff00) >> 8;
sir[2] = (p & 0x0000ff);
rinsum += sir[0];
ginsum += sir[1];
binsum += sir[2];
rsum += rinsum;
gsum += ginsum;
bsum += binsum;
stackpointer = (stackpointer + 1) % div;
sir = stack[(stackpointer) % div];
routsum += sir[0];
goutsum += sir[1];
boutsum += sir[2];
rinsum -= sir[0];
ginsum -= sir[1];
binsum -= sir[2];
yi++;
}
yw += w;
}
for (x = 0; x < w; x++) {
rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
yp = -radius * w;
for (i = -radius; i <= radius; i++) {
yi = Math.max(0, yp) + x;
sir = stack[i + radius];
sir[0] = r[yi];
sir[1] = g[yi];
sir[2] = b[yi];
rbs = r1 - Math.abs(i);
rsum += r[yi] * rbs;
gsum += g[yi] * rbs;
bsum += b[yi] * rbs;
if (i > 0) {
rinsum += sir[0];
ginsum += sir[1];
binsum += sir[2];
} else {
routsum += sir[0];
goutsum += sir[1];
boutsum += sir[2];
}
if (i < hm) {
yp += w;
}
}
yi = x;
stackpointer = radius;
for (y = 0; y < h; y++) {
// Preserve alpha channel: ( 0xff000000 & pix[yi] )
pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];
rsum -= routsum;
gsum -= goutsum;
bsum -= boutsum;
stackstart = stackpointer - radius + div;
sir = stack[stackstart % div];
routsum -= sir[0];
goutsum -= sir[1];
boutsum -= sir[2];
if (x == 0) {
vmin[y] = Math.min(y + r1, hm) * w;
}
p = x + vmin[y];
sir[0] = r[p];
sir[1] = g[p];
sir[2] = b[p];
rinsum += sir[0];
ginsum += sir[1];
binsum += sir[2];
rsum += rinsum;
gsum += ginsum;
bsum += binsum;
stackpointer = (stackpointer + 1) % div;
sir = stack[stackpointer];
routsum += sir[0];
goutsum += sir[1];
boutsum += sir[2];
rinsum -= sir[0];
ginsum -= sir[1];
binsum -= sir[2];
yi += w;
}
}
bitmap.setPixels(pix, 0, w, 0, 0, w, h);
return (bitmap);
}