[FEATURE] Add `Color` class

[guibranco]

Description

Add Color class with RGB helpers.

Tech notes

<?php

namespace GuiBranco\Pancake;

class Color
{
    public static function luminance($color)
    {
        $rgb = self::hex2rgb($color);

        return ($rgb['red'] * 0.2126) + ($rgb['green'] * 0.7152) + ($rgb['blue'] * 0.0722);
    }

    public static function hex2rgb($color)
    {
        if (strlen($color) == 3) {
            $color = $color[0] . $color[0] . $color[1] . $color[1] . $color[2] . $color[2];
        }
        return array(
            'red' => hexdec($color[0] . $color[1]),
            'green' => hexdec($color[2] . $color[3]),
            'blue' => hexdec($color[4] . $color[5]),
        );
    }

    public static function generateColorFromText($text, $minBrightness = 100, $spec = 10)
    {
        if (!is_int($minBrightness)) {
            throw new Exception("$minBrightness is not an integer");
        }
        if (!is_int($spec)) {
            throw new Exception("$spec is not an integer");
        }
        if ($spec < 2 || $spec > 10) {
            throw new Exception("$spec is out of range");
        }
        if ($minBrightness < 0 || $minBrightness > 255) {
            throw new Exception("$minBrightness is out of range");
        }

        $hash = md5($text);
        $colors = array();
        for ($i = 0; $i < 3; $i++) {
            $current = round(((hexdec(substr($hash, $spec * $i, $spec))) / hexdec(str_pad('', $spec, 'F'))) * 255);
            $colors[$i] = max(array($current, $minBrightness));
        }

        if ($minBrightness > 0) {
            while (array_sum($colors) / 3 < $minBrightness) {
                for ($i = 0; $i < 3; $i++) {
                    $colors[$i] += 10;
                }
            }
        }

        $output = '';

        for ($i = 0; $i < 3; $i++) {
            $output .= str_pad(dechex($colors[$i]), 2, 0, STR_PAD_LEFT);
        }

        return $output;
    }
}

Additional information

⚠️ 🚨 Add documentation and tests

[gvieiragoulart]

What do you think about using a constructor for color objects with validation?

Currently, we use static functions to create colors. We could explore using a constructor instead. This would allow us to create colors from RGB or hex values and also implement some validation that the users can input on functions

[guibranco]

@gvieiragoulart I agree! Do you want to assign this to you? Are you keen to work with it?

[gvieiragoulart]

@gvieiragoulart I agree! Do you want to assign this to you? Are you keen to work with it?

Yes! please, you can assign to me. I'll work on that