软油漆桶填充：颜色平等 [英] Soft Paint Bucket Fill: Colour Equality

问题描述

我在做一个小的应用程序，孩子们可以填补preSET插图颜色。我已经成功地实现用颜色填充argorithm一个MS-烤漆风格的油漆桶。然而，邻近的图像元素的像素的边缘悬空的，因为行是反走样。这是因为不论是否为填补目前的状况是 colourAtCurrentPixel == colourToReplace ，它不会在混合像素的线工作。 （颜色是RGB uints）

我想添加一个平滑/ treshold选项像Photoshop等复杂的工具，但什么是算法来确定两种颜色之间的平等/距离？

如果（匹配（像素（X，Y），colourToReplace）与setPixel（X，Y，colourToReplaceWith）

如何填写匹配（）？

下面，图像​​（左为的情况下，正确的是希望）

下面是我目前的全code：

 变种B：的BitmapData = settings.background;
            块（）;

            从变种：UINT = b.getPixel（X，Y）;


            VAR问：数组= [];


            VAR XX：INT;
            VAR YY：INT;
            变种W：INT = b.width;
            VAR H：INT = b.height;
            q.push（Y * W + X）;
            而（q.length！= 0）{
                VAR XY：INT = q.shift（）;
                XX = XY％（重量）;
                YY =（XY  -  XX）/ W;
                如果（b.getPixel（XX，YY）==从）{//＆LT;  - 要替换​​该行
                    b.setPixel（XX，YY，到）;
                    如果（ⅹⅹ！= 0）q.push（XY-1）;
                    如果（！XX =瓦特-1）q.push（XY + 1）;
                    如果（YY！= 0）q.push（XY-w）的;
                    如果（YY = H-1！）q.push（XY + W）;
                }
            }
            b.unlock（空）;
 

解决方案

唉，我想最自然的方法是计算之间颜色的差异。实现一个合理的值，应该计算每个信道的区别。没有测试过，但下面应该工作：

 常量perChanThreshold：UINT = 5;
常量overallThreshold：UINT = perChanThreshold * perChanThreshold * 3;
功能匹配（来源：UINT，目标：UINT）：布尔{
    VAR差异：UINT = 0，chanDiff：单元;
    对于（VAR我：= 0;我3;;我++）{
        chanDiff =（来源＆GT;＆GT;（I * 8））及0xFF的;
        差异+ = chanDiff * chanDiff;
    }
    返回DIFF＆LT; = overallThreshold;
}
 

I'm making a small app where children can fill preset illustrations with colours. I've succesfully implemented an MS-paint style paint bucket using the flood fill argorithm. However, near the edges of image elements pixels are left unfilled, because the lines are anti-aliased. This is because the current condition on whether to fill is colourAtCurrentPixel == colourToReplace, which doesn't work on the blended pixels at the lines. (the colours are RGB uints)

I'd like to add a smoothing/treshold option like in Photoshop and other sophisticated tools, but what's the algorithm to determine the equality/distance between two colours?

if (match(pixel(x,y), colourToReplace) setpixel(x,y,colourToReplaceWith)

How to fill in match()?

Here, an image (left is situation, right is wanted)

Here's my current full code:

            var b:BitmapData = settings.background;
            b.lock();

            var from:uint = b.getPixel(x,y);


            var q:Array = [];


            var xx:int;
            var yy:int;
            var w:int = b.width;
            var h:int = b.height;
            q.push(y*w + x);
            while (q.length != 0) {
                var xy:int = q.shift();
                xx = xy % w;
                yy = (xy - xx) / w;
                if (b.getPixel(xx,yy) == from) { //<- want to replace this line
                    b.setPixel(xx,yy,to);
                    if (xx != 0) q.push(xy-1);
                    if (xx != w-1) q.push(xy+1);
                    if (yy != 0) q.push(xy-w);
                    if (yy != h-1) q.push(xy+w);
                }
            }
            b.unlock(null);

解决方案

well, i guess the most natural approach is to calculate the difference between to colors. to achieve a sensible value, one should calculate the difference per channel. haven't tested it, but the following should work:

const perChanThreshold:uint = 5;
const overallThreshold:uint = perChanThreshold * perChanThreshold * 3;
function match(source:uint, target:uint):Boolean {
    var diff:uint = 0, chanDiff:uint;
    for (var i:int = 0; i < 3; i++) {
        chanDiff = (source >> (i * 8)) & 0xFF;
        diff += chanDiff * chanDiff;
    }
    return diff <= overallThreshold;
}

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