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<?php |
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|
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namespace Svg; |
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|
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class CssLength |
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{ |
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/** |
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* Array of valid css length units. |
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* Should be pre-sorted by unit text length so no earlier length can be |
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* contained within a latter (eg. 'in' within 'vmin'). |
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* |
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* @var string[] |
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*/ |
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protected static $units = [ |
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'vmax', |
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'vmin', |
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'rem', |
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'px', |
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'pt', |
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'cm', |
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'mm', |
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'in', |
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'pc', |
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'em', |
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'ex', |
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'ch', |
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'vw', |
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'vh', |
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'%', |
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'q', |
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]; |
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|
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/** |
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* A list of units that are inch-relative, and their unit division within an inch. |
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* |
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* @var array<string, float> |
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*/ |
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protected static $inchDivisions = [ |
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'in' => 1, |
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'cm' => 2.54, |
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'mm' => 25.4, |
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'q' => 101.6, |
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'pc' => 6, |
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'pt' => 72, |
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]; |
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|
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/** |
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* The CSS length unit indicator. |
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* Will be lower-case and one of the units listed in the '$units' array or empty. |
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* |
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* @var string |
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*/ |
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protected $unit = ''; |
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|
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/** |
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* The numeric value of the given length. |
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* |
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* @var float |
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*/ |
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protected $value = 0; |
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|
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/** |
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* The original unparsed length provided. |
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* |
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* @var string |
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*/ |
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protected $unparsed; |
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|
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public function __construct(string $length) |
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{ |
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$this->unparsed = $length; |
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$this->parseLengthComponents($length); |
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} |
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|
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/** |
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* Parse out the unit and value components from the given string length. |
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*/ |
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protected function parseLengthComponents(string $length): void |
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{ |
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$length = strtolower($length); |
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|
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foreach (self::$units as $unit) { |
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$pos = strpos($length, $unit); |
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if ($pos) { |
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$this->value = floatval(substr($length, 0, $pos)); |
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$this->unit = $unit; |
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return; |
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} |
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} |
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|
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$this->unit = ''; |
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$this->value = floatval($length); |
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} |
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|
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/** |
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* Get the unit type of this css length. |
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* Units are standardised to be lower-cased. |
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* |
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* @return string |
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*/ |
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public function getUnit(): string |
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{ |
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return $this->unit; |
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} |
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|
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/** |
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* Get this CSS length in the equivalent pixel count size. |
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* |
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* @param float $referenceSize |
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* @param float $dpi |
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* |
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* @return float |
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*/ |
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public function toPixels(float $referenceSize = 11.0, float $dpi = 96.0): float |
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{ |
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// Standard relative units |
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if (in_array($this->unit, ['em', 'rem', 'ex', 'ch'])) { |
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return $this->value * $referenceSize; |
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} |
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|
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// Percentage relative units |
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if (in_array($this->unit, ['%', 'vw', 'vh', 'vmin', 'vmax'])) { |
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return $this->value * ($referenceSize / 100); |
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} |
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|
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// Inch relative units |
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if (in_array($this->unit, array_keys(static::$inchDivisions))) { |
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$inchValue = $this->value * $dpi; |
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$division = static::$inchDivisions[$this->unit]; |
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return $inchValue / $division; |
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} |
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|
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return $this->value; |
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} |
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} |
