PHPBench Color/Gradient V/O / Collections

Color.php

<?php

namespace PhpBench\Expression\ColorMap\Util;

use RuntimeException;

final class Color
{
    /**
     * @var int
     */
    private $red;

    /**
     * @var int
     */
    private $green;

    /**
     * @var int
     */
    private $blue;

    public function __construct(int $red, int $green, int $blue)
    {
        $this->red = $red;
        $this->green = $green;
        $this->blue = $blue;
    }

    public static function fromHex(string $hex): self
    {
        $hexRgb = sscanf(ltrim($hex, '#'), '%02s%02s%02s');
        if (!is_array($hexRgb)) {
            throw new RuntimeException(sprintf(
                'Could not parse hex color "%s"', $hex
            ));
        }

        /** @phpstan-ignore-next-line */
        return new self(...array_map('hexdec', $hexRgb));
    }

    /**
     * @return array{int,int,int}
     */
    public function toTuple(): array
    {
        return [
            $this->red,
            $this->green,
            $this->blue
        ];
    }

    public function toHex(): string
    {
        return implode('', array_map(function (int $number) {
            return sprintf('%02s', dechex($number));
        }, $this->toTuple()));
    }
}

Gradient.php

<?php

namespace PhpBench\Expression\ColorMap\Util;

use RuntimeException;
use function array_fill;
use function array_key_first;
use function array_key_last;
use function array_unshift;
use function dechex;
use function sscanf;

final class Gradient
{
    /**
     * @var Color[]
     */
    private $colors;

    private function __construct(Color ...$colors)
    {
        $this->colors = $colors;
    }

    /**
     * @return Color[]
     */
    public function toArray(): array
    {
        return $this->colors;
    }

    public static function start(Color $start): self
    {
        return new self($start);
    }

    public function end(): Color
    {
        return $this->colors[array_key_last($this->colors)];
    }

    public function to(Color $end, int $steps): self
    {
        if ($steps <= 0) {
            throw new RuntimeException(sprintf(
                'Number of steps must be more than zero, got "%s"', $steps
            ));
        }

        $gradient = [];
        $start = $this->end()->toTuple();
        $end= $end->toTuple();

        for ($i = 0; $i <= 2; $i++) {
            $cStart = $start[$i];
            $cEnd = $end[$i];

            $step = abs($cStart - $cEnd) / $steps;

            if ($step === 0) {
                $gradient[$i] = array_fill(0, $steps + 1, $cStart);
                continue;
            }
            $gradient[$i] = range($cStart, $cEnd, $step);
        }

        $colors = array_merge($this->colors, array_map(function (int $r, int $g, int $b) {
            return new Color($r,$g,$b);
        }, ...$gradient));

        // remove the start color as it's already present
        array_shift($colors);

        return new self(...$colors);
    }

    public function colorAtIndex(int $index): Color
    {
        if (!isset($this->colors[$index])) {
            throw new RuntimeException(sprintf(
                'Color index is out of range "%s" (%s:%s)',
                $index, array_key_first($this->colors), array_key_last($this->colors)
            ));
        }

        return $this->colors[$index];
    }
}

usage.php

<?php

                $color = Gradient::start(
                    Color::fromHex(self::GREEN)
                )->to(
                    Color::fromHex(self::BASE2), 100
                )->to(
                    Color::fromHex(self::RED), 100
                )->colorAtIndex($value + 100)->toHex();