97 lines
2.6 KiB
PHP
97 lines
2.6 KiB
PHP
<?php
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namespace Misuzu;
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use InvalidArgumentException;
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class Colour {
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private const FLAG_INHERIT = 0x40000000;
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private const READABILITY_THRESHOLD = 186;
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private const LUMINANCE_WEIGHT_RED = .299;
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private const LUMINANCE_WEIGHT_GREEN = .587;
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private const LUMINANCE_WEIGHT_BLUE = .114;
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private int $raw = 0;
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public function __construct(?int $raw = 0) {
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$this->raw = ($raw ?? 0) & 0x7FFFFFFF;
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}
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public static function none(): self {
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return new Colour(self::FLAG_INHERIT);
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}
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public static function fromRgb(int $red, int $green, int $blue): self {
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$raw = (($red & 0xFF) << 16)
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| (($green & 0xFF) << 8)
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| ($blue & 0xFF);
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return new Colour($raw);
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}
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public static function fromHex(string $hex): self {
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if($hex[0] === '#')
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$hex = mb_substr($hex, 1);
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if(!ctype_xdigit($hex))
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throw new InvalidArgumentException('Argument contains invalid characters.');
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$length = mb_strlen($hex);
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if($length === 3) {
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$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
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} elseif($length !== 6) {
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throw new InvalidArgumentException('Argument is not a hex string.');
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}
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return new Colour(hexdec($hex));
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}
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public function getRaw(): int {
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return $this->raw;
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}
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public function getInherit(): bool {
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return ($this->getRaw() & self::FLAG_INHERIT) > 0;
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}
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public function getRed(): int {
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return ($this->getRaw() & 0xFF0000) >> 16;
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}
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public function getGreen(): int {
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return ($this->getRaw() & 0xFF00) >> 8;
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}
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public function getBlue(): int {
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return ($this->getRaw() & 0xFF);
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}
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public function getLuminance(): float {
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return self::LUMINANCE_WEIGHT_RED * $this->getRed()
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+ self::LUMINANCE_WEIGHT_GREEN * $this->getGreen()
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+ self::LUMINANCE_WEIGHT_BLUE * $this->getBlue();
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}
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public function getHex(): string {
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return str_pad(dechex($this->getRaw() & 0xFFFFFF), 6, '0', STR_PAD_LEFT);
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}
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public function getCSS(): string {
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if($this->getInherit())
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return 'inherit';
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return '#' . $this->getHex();
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}
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public function extractCSSContract(
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string $dark = 'dark', string $light = 'light', bool $inheritIsDark = true
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): string {
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if($this->getInherit())
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return $inheritIsDark ? $dark : $light;
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return $this->getLuminance() > self::READABILITY_THRESHOLD ? $dark : $light;
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}
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public function __toString() {
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return $this->getCSS();
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}
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}
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