Android RenderScript高斯模糊

public static Bitmap blurBitmap(Bitmap bitmap, float radius, Context context) { 
    //创建渲染脚本上下文 
    RenderScript rs = RenderScript.create(context); 
 
    //为位图分配内存 
    Allocation allocation = Allocation.createFromBitmap(rs, bitmap); 
 
    Type t = allocation.getType(); 
 
    //用同样的类型创建内存，一般用这两种方式创建 Allocation 
    Allocation blurredAllocation = Allocation.createTyped(rs, t); 
 
    //创建高斯渲染脚本  
    ScriptIntrinsicBlur blurScript = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs)); 
    //设置模糊半径 (maximum 25.0) 
    blurScript.setRadius(radius); 
    //为脚本设置输入参数  
    blurScript.setInput(allocation); 
    //调用脚本 结果存入 blurredAllocation中 
    blurScript.forEach(blurredAllocation); 
 
    //把脚本结果存入位图中 因为为native层渲染，所以结果需要复制到上层 
    blurredAllocation.copyTo(bitmap); 
 
    //Destroy everything to free memory 
    allocation.destroy(); 
    blurredAllocation.destroy(); 
    blurScript.destroy(); 
    t.destroy(); 
 
    return bitmap; 
  }