PHP红色到绿色RGB颜色热图 [英] PHP Red to Green RGB Color Heatmap

问题描述

我似乎无法弄清楚.我有一组缩放的值(0 ... 1)，需要将它们与颜色相关联.最高(1)为红色，最低(0)为绿色.

I can't seem to get this figured out. I have a scaled set of values (0...1) that I need to associate colors with. The highest (1) being red and the lowest (0) being green.

我似乎找不到如何获得介于0和1之间的值的红色和绿色之间的RGB颜色.

I cannot seem to find how to get an RGB color between red and green for a value that is between 0 and 1.

这是我要用于缩放值的缩放函数:

Here is my scaling function I am going to use to scale the values:

function scale_value($value, $srcmin, $srcmax, $destmin = 0, $destmax = 1)
{
    # How Far In Source Range Are We
    $pos = (($value - $srcmin) / ($srcmax - $srcmin));
    return ($pos * ($destmax - $destmin)) + $destmin;
}

我认为将它们从0缩放到1将使下一个我正在苦苦挣扎的部分变得容易得多.

I figured scaling them from 0 to 1 will make the next part I am struggling with much easier.

这是我想出的一个非常糟糕的尝试，失败非常严重.

Here is one very crummy attempt at doing this I came up with, failed pretty badly.

function make_color($value)
{
    $red = $value > 0.5
       ? (1 - 2 * ($value - 0.5) / 1)
       : 1;
    $green = $value > 0.5
        ? 1
        : 2 * ($value / 1);
    $blue = 0;
    return "rgb($red,$green,$blue)";
}

是否有人有使用PHP来确定用于介于1和0之间的值的颜色的经验?

Does anyone have any experience using PHP to determine the color to use for a value that falls between 1 and 0?

推荐答案

找到了一个解决方案，将JS实现的解决方案转换为

Found a solution, converting the JS implemented solution posted here to PHP and reversing the Red to Green polarity so Red was high, Green was low.

看起来像这样:

/**
 * @param $value
 * @param integer|float $min
 * @param integer|float $max
 * @return string
 */
function make_color($value, $min = 0, $max = .5)
{
    $ratio = $value;
    if ($min > 0 || $max < 1) {
        if ($value < $min) {
            $ratio = 1;
        } else if ($value > $max) {
            $ratio = 0;
        } else {
            $range = $min - $max;
            $ratio = ($value - $max) / $range;
        }
    }

    $hue = ($ratio * 1.2) / 3.60;
    $rgb = hsl_to_rgb($hue, 1, .5);

    $r = round($rgb['r'], 0);
    $g = round($rgb['g'], 0);
    $b = round($rgb['b'], 0);

    return "rgb($r,$g,$b)";
}

这也依赖于HSL到RGB转换器，我发现它是

This also relies on an HSL to RGB translator, which I found on this post. This ends up giving me a pretty nice result:

感谢您的帮助.

这篇关于PHP红色到绿色RGB颜色热图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！