Android模糊处理实现图片毛玻璃效果

本文实例讲解了Android 虚化图片、模糊图片、图片毛玻璃效果的实现方法，具体内容如下

效果如图：

在Android可以用RenderScript方便的实现这个方法：

private void blur(Bitmap bkg, View view, float radius) { 
  Bitmap overlay = Bitmap.createBitmap(view.getMeasuredWidth(), view.getMeasuredHeight(), Bitmap.Config.ARGB_8888); 
  Canvas canvas = new Canvas(overlay); 
  canvas.drawBitmap(bkg, -view.getLeft(), -view.getTop(), null); 
  RenderScript rs = RenderScript.create(this); 
  Allocation overlayAlloc = Allocation.createFromBitmap(rs, overlay); 
  ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(rs, overlayAlloc.getElement()); 
  blur.setInput(overlayAlloc); 
  blur.setRadius(radius); 
  blur.forEach(overlayAlloc); 
  overlayAlloc.copyTo(overlay); 
  view.setBackground(new BitmapDrawable(getResources(), overlay)); 
  rs.destroy(); 
 } 

但是RenderScript的这个方法需要Android API17，也就说需要在Android 4.2上才能实现。
低于Android4.2可以用Java原生代码实现。但是效率会低不少：这完全是一种妥协的方式，不推荐。

/* 
  * This method was copied from http://stackoverflow.com/a/10028267/694378. 
  * The only modifications I've made are to remove a couple of Log 
  * statements which could slow things down slightly. 
  */ 
 public Bitmap fastblur(Bitmap sentBitmap, int radius) { 
 
  // Stack Blur v1.0 from 
  // http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html 
  // 
  // Java Author: Mario Klingemann <mario at quasimondo.com> 
  // http://incubator.quasimondo.com 
  // created Feburary 29, 2004 
  // Android port : Yahel Bouaziz <yahel at kayenko.com> 
  // http://www.kayenko.com 
  // ported april 5th, 2012 
 
  // This is a compromise between Gaussian Blur and Box blur 
  // It creates much better looking blurs than Box Blur, but is 
  // 7x faster than my Gaussian Blur implementation. 
  // 
  // I called it Stack Blur because this describes best how this 
  // filter works internally: it creates a kind of moving stack 
  // of colors whilst scanning through the image. Thereby it 
  // just has to add one new block of color to the right side 
  // of the stack and remove the leftmost color. The remaining 
  // colors on the topmost layer of the stack are either added on 
  // or reduced by one, depending on if they are on the right or 
  // on the left side of the stack. 
  // 
  // If you are using this algorithm in your code please add 
  // the following line: 
  // 
  // Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com> 
 
  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]; 
  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); 
 } 

以上就是本文的全部内容，希望对大家学习Android软件编程有所帮助。