Android实现图片毛玻璃背景效果

import android.content.Context; 
import android.graphics.Bitmap; 
 
/** 
 * Created by abel.zhang on 2016/8/9. 
 * 图片的毛玻璃效果 
 */ 
public class GsdFastBlur { 
 
 /** 
  * 
  * @param context 
  * @param sentBitmap 
  * @param radius 12 模糊程度 
  * @return 
  */ 
 public static Bitmap fastblur(Context context, Bitmap sentBitmap, int radius) { 
 
  if (sentBitmap==null){ 
   return null; 
  } 
  Bitmap bitmap =null; 
  try { 
   bitmap = sentBitmap.copy(sentBitmap.getConfig(), true); 
  }catch (Exception e){ 
   e.printStackTrace(); 
   return null; 
  } 
 
 
  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 temp = 256 * divsum; 
  int dv[] = new int[temp]; 
  for (i = 0; i < temp; 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; 
   } 
  } 
 
//  Log.e("pix", w + " " + h + " " + pix.length); 
  bitmap.setPixels(pix, 0, w, 0, 0, w, h); 
  return (bitmap); 
 } 
 
}