Viewing file:  CssLength.php (3 KB) -rw-r--r--
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<?php
namespace Svg;
class CssLength
{
/**
* Array of valid css length units.
* Should be pre-sorted by unit text length so no earlier length can be
* contained within a latter (eg. 'in' within 'vmin').
*
* @var string[]
*/
protected static $units = [
'vmax',
'vmin',
'rem',
'px',
'pt',
'cm',
'mm',
'in',
'pc',
'em',
'ex',
'ch',
'vw',
'vh',
'%',
'q',
];
/**
* A list of units that are inch-relative, and their unit division within an inch.
*
* @var array<string, float>
*/
protected static $inchDivisions = [
'in' => 1,
'cm' => 2.54,
'mm' => 25.4,
'q' => 101.6,
'pc' => 6,
'pt' => 72,
];
/**
* The CSS length unit indicator.
* Will be lower-case and one of the units listed in the '$units' array or empty.
*
* @var string
*/
protected $unit = '';
/**
* The numeric value of the given length.
*
* @var float
*/
protected $value = 0;
/**
* The original unparsed length provided.
*
* @var string
*/
protected $unparsed;
public function __construct(string $length)
{
$this->unparsed = $length;
$this->parseLengthComponents($length);
}
/**
* Parse out the unit and value components from the given string length.
*/
protected function parseLengthComponents(string $length): void
{
$length = strtolower($length);
foreach (self::$units as $unit) {
$pos = strpos($length, $unit);
if ($pos) {
$this->value = floatval(substr($length, 0, $pos));
$this->unit = $unit;
return;
}
}
$this->unit = '';
$this->value = floatval($length);
}
/**
* Get the unit type of this css length.
* Units are standardised to be lower-cased.
*
* @return string
*/
public function getUnit(): string
{
return $this->unit;
}
/**
* Get this CSS length in the equivalent pixel count size.
*
* @param float $referenceSize
* @param float $dpi
*
* @return float
*/
public function toPixels(float $referenceSize = 11.0, float $dpi = 96.0): float
{
// Standard relative units
if (in_array($this->unit, ['em', 'rem', 'ex', 'ch'])) {
return $this->value * $referenceSize;
}
// Percentage relative units
if (in_array($this->unit, ['%', 'vw', 'vh', 'vmin', 'vmax'])) {
return $this->value * ($referenceSize / 100);
}
// Inch relative units
if (in_array($this->unit, array_keys(static::$inchDivisions))) {
$inchValue = $this->value * $dpi;
$division = static::$inchDivisions[$this->unit];
return $inchValue / $division;
}
return $this->value;
}
}
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