图片处理--冰冻特效

1、算法

将对rgb 值依次做better处理，同时再下一步用到上一步已经处理好的值。

 public Bitmap render(Bitmap bitmap)
  {
    if(bitmap == null)return null;

    int width = bitmap.getWidth();
    int height = bitmap.getHeight();

    int[] pixels = new int[width * height];
    bitmap.getPixels(pixels ,0 , width , 0 , 0 , width , height);
    for(int i=0 ; i<height ; i++)
    {
      for(int j=0 ; j<width ; j++)
      {
        int pixel = pixels[i*width +j];
        int r = (pixel & 0x00ff0000)>>16;
        int g = (pixel & 0x0000ff00)>>8;
        int b = (pixel & 0x000000ff);

        r = better(r-g-b);
        g = better(g-r-b);
        b = better(b-r-g);
        pixels[i*width +j] = (pixel & 0xff000000) + (r<<16)+ (g<<8) +b;
      }
    }

    return Bitmap.createBitmap(pixels ,width , height , Config.ARGB_8888);
  }

public int better(int value)
{
  value = value *3 /2;

  if(value<0)
  {
    value = -value;
  }

  if(value>255)
  {
    value = 255;
  }
  return value;
}