PHP function that converts number from given range into a color from given gradient of multiple colors

numberToColor

// See example: https://image.prntscr.com/image/cTIv8JkLR7yWEQxVev9SyA.jpeg

function numberToColor($value, $min, $max, $gradientColors = null)
{
    // Ensure value is in range
    if ($value < $min) {
        $value = $min;
    }
    if ($value > $max) {
        $value = $max;
    }

    // Normalize min-max range to [0, positive_value]
    $max -= $min;
    $value -= $min;
    $min = 0;

    // Calculate distance from min to max in [0,1]
    $distFromMin = $value / $max;

    // Define start and end color
    if (count($gradientColors) == 0) {
        return self::colorFromRange($value, $min, $max, ['#CC0000', '#EEEE00', '#00FF00']);
    } else if (count($gradientColors) == 2) {
        $startColor = $gradientColors[0];
        $endColor = $gradientColors[1];
    } else if (count($gradientColors) > 2) {
        $startColor = $gradientColors[floor($distFromMin * (count($gradientColors) - 1))];
        $endColor = $gradientColors[ceil($distFromMin * (count($gradientColors) - 1))];

        $distFromMin *= count($gradientColors) - 1;
        while ($distFromMin > 1) {
            $distFromMin--;
        }
    } else {
        die("Please pass more than one color or null to use default red-green colors.");
    }

    // Remove hex from string
    if ($startColor[0] === '#') {
        $startColor = substr($startColor, 1);
    }
    if ($endColor[0] === '#') {
        $endColor = substr($endColor, 1);
    }

    // Parse hex
    list($ra, $ga, $ba) = sscanf("#$startColor", "#%02x%02x%02x");
    list($rz, $gz, $bz) = sscanf("#$endColor", "#%02x%02x%02x");

    // Get rgb based on
    $distFromMin = $distFromMin;
    $distDiff = 1 - $distFromMin;
    $r = intval(($rz * $distFromMin) + ($ra * $distDiff));
    $r = min(max(0, $r), 255);
    $g = intval(($gz * $distFromMin) + ($ga * $distDiff));
    $g = min(max(0, $g), 255);
    $b = intval(($bz * $distFromMin) + ($ba * $distDiff));
    $b = min(max(0, $b), 255);

    // Convert rgb back to hex
    $rgbColorAsHex = '#' .
        str_pad(dechex($r), 2, "0", STR_PAD_LEFT) .
        str_pad(dechex($g), 2, "0", STR_PAD_LEFT) .
        str_pad(dechex($b), 2, "0", STR_PAD_LEFT);

    return $rgbColorAsHex;
}

// ====================================================

for ($i = 0; $i <= 20; $i++) {
    $color = \App\Helpers\ColorHelper::colorFromRange(
    $i, 0, 20
    );

    echo "<div style='font-weight:bold; display:inline-block; width:30px; font-size:16px; color: black; background-color:" . $color . "; text-align:center'>$i</div>";
}

echo "<br /><br />";

for ($i = 0; $i <= 20; $i++) {
    $color = \App\Helpers\ColorHelper::colorFromRange(
    $i, 0, 20, ['#CC0000', '#EEEE00', '#00AA00', '#0088EE']
    );

    echo "<div style='font-weight:bold; display:inline-block; width:30px; font-size:16px; color: black; background-color:" . $color . "; text-align:center'>$i</div>";
}
die;

Really usefull function, thanks !

Change line 23 from :
return self::colorFromRange($value, $min, $max, ['#CC0000', '#EEEE00', '#00FF00']);
to :
return numberToColor($value, $min, $max, ['#CC0000', '#EEEE00', '#00FF00']);

very nice!
thanks a lot!

thanks 4 ur code! =)

very usefull... for a nice result... thx