高斯模糊的实现
今天设计提出来一个需求，第一耳听到时，我就蒙逼了。
她说：”这个头像的背景你就用用户头像的图标高斯模糊100 + 黑色的蒙层30%的不透明“。
后来经过我的不懈努力，在网上找到了完美的解决方案，惊奇的发现，所谓高大上的高斯模糊又称为”毛玻璃效果“。说毛玻璃效果就很easy了，网上一搜一大把的实现方式，结果都是使用的一个叫做BlurUtil里面的fastblur的方法。
实现起来相当的方便。
/**
* 毛玻璃处理类
* @author ycf
*/
public class BlurUtil
{
@SuppressLint("NewApi")
public static Bitmap fastblur(Context context, Bitmap sentBitmap, int radius)
{
if (VERSION.SDK_INT > 16) //判断SDK的版本，可以更换
{
Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
final RenderScript rs = RenderScript.create(context);
final Allocation input = Allocation.createFromBitmap(rs,sentBitmap, Allocation.MipmapControl.MIPMAP_NONE,Allocation.USAGE_SCRIPT);
final Allocation output = Allocation.createTyped(rs,input.getType());
final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs,Element.U8_4(rs));
script.setRadius(radius);/* e.g. 3.f */
script.setInput(input);
script.forEach(output);
output.copyTo(bitmap);
return bitmap;
}
Bitmap 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];
Log.e("pix", w + " " + h + " " + pix.length);
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++)
{
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);
}
}