content: package com.liyi.sutils.utils.graphic.blur;
  
  
  import android.graphics.Bitmap;
  
  
  /**
   * 国外一位大神写的图片模糊算法
   */
  public final class FastBlur {
      public static Bitmap blur(Bitmap sentBitmap,int radius, boolean canReuseInBitmap) {
          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);
      }
  }