的Flex /动作脚本白色到透明 [英] Flex/Actionscript White to Transparent

问题描述

我想写的东西在我的Flex 3应用程序动作，将采取一个图像，当用户点击一个按钮，它会去掉所有的白色（ISH）像素，并将其转换成透明的，我说白了（ ISH），因为我曾试图完全白色的，但我得到了很多周围的边缘文物。我已经变得有点接近使用以下code：

I am trying to write something in my Flex 3 application with actionscript that will take an image and when a user clicks a button, it will strip out all the white(ish) pixels and convert them to transparent, I say white(ish) because I have tried exactly white, but I get a lot of artifacts around the edges. I have gotten somewhat close using the following code:

targetBitmapData.threshold(sourceBitmapData, sourceBitmapData.rect, new Point(0,0), ">=", 0xFFf7f0f2, 0x00FFFFFF, 0xFFFFFFFF, true);

不过，这也使得红色或者黄色消失。为什么这样做呢？我不完全知道如何使这项工作。难道还有其他的功能，更适合我的需求？

However, it also makes red or yellows disappear. Why is it doing this? I'm not exactly sure how to make this work. Is there another function that is better suited for my needs?

推荐答案

我和一个朋友试图做到这一点而回了一个项目，发现写，这是否在ActionScript是难以置信的慢行内的方法。你必须扫描每个像素，并做了计算反对，但PixelBender做它被证明是闪电般速度（如果你可以使用Flash 10，否则你坚持了缓慢的）。

A friend and I were trying to do this a while back for a project, and found writing an inline method that does this in ActionScript to be incredibly slow. You have to scan each pixel and do a computation against it, but doing it with PixelBender proved to be lightning fast (if you can use Flash 10, otherwise your stuck with slow AS).

在Pixel Bender的code是这样的：

The pixel bender code looks like:

input image4 src;
output float4 dst;

// How close of a match you want
parameter float threshold
<
  minValue:     0.0;
  maxValue:     1.0;
  defaultValue: 0.4;
>;

// Color you are matching against.
parameter float3 color
<
  defaultValue: float3(1.0, 1.0, 1.0);
>;

void evaluatePixel()
{
  float4 current = sampleNearest(src, outCoord());
  dst = float4((distance(current.rgb, color) < threshold) ? 0.0 : current);
}

如果你需要做的，你可以使用这样的：

If you need to do it in AS you can use something like:

function threshold(source:BitmapData, dest:BitmapData, color:uint, threshold:Number) {
  dest.lock();

  var x:uint, y:uint;
  for (y = 0; y < source.height; y++) {
    for (x = 0; x < source.width; x++) {
      var c1:uint = source.getPixel(x, y);
      var c2:uint = color;
      var rx:uint = Math.abs(((c1 & 0xff0000) >> 16) - ((c2 & 0xff0000) >> 16));
      var gx:uint = Math.abs(((c1 & 0xff00) >> 8) - ((c2 & 0xff00) >> 8));
      var bx:uint = Math.abs((c1 & 0xff) - (c2 & 0xff));

      var dist = Math.sqrt(rx*rx + gx*gx + bx*bx);

      if (dist <= threshold)
        dest.setPixel(x, y, 0x00ffffff);
      else
        dest.setPixel(x, y, c1);
    }
  }
  dest.unlock();
}

这篇关于的Flex /动作脚本白色到透明的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！