. */ declare(strict_types=1); namespace Fisharebest\Webtrees\Statistics\Service; use function array_map; use function hexdec; use function ltrim; use function round; use function sprintf; /** * Functions for managing and manipulating colors. */ class ColorService { /** * Interpolates the number of color steps between a given start and end color. * * @param string $startColor The start color * @param string $endColor The end color * @param int $steps The number of steps to interpolate * * @return array */ public function interpolateRgb(string $startColor, string $endColor, int $steps): array { if (!$steps) { return []; } $s = $this->hexToRgb($startColor); $e = $this->hexToRgb($endColor); $colors = []; $factorR = ($e[0] - $s[0]) / $steps; $factorG = ($e[1] - $s[1]) / $steps; $factorB = ($e[2] - $s[2]) / $steps; for ($x = 1; $x < $steps; ++$x) { $colors[] = $this->rgbToHex( (int) round($s[0] + ($factorR * $x)), (int) round($s[1] + ($factorG * $x)), (int) round($s[2] + ($factorB * $x)) ); } $colors[] = $this->rgbToHex($e[0], $e[1], $e[2]); return $colors; } /** * Converts the color values to the HTML hex representation. * * @param int $r The red color value * @param int $g The green color value * @param int $b The blue color value * * @return string */ private function rgbToHex(int $r, int $g, int $b): string { return sprintf('#%02x%02x%02x', $r, $g, $b); } /** * Converts the HTML color hex representation to an array of color values. * * @param string $hex The HTML hex color code * * @return array */ private function hexToRgb(string $hex): array { return array_map(function (string $hex): int { return (int) hexdec($hex); }, str_split(ltrim($hex, '#'), 2)); } }