HTMLPurifier_UnitConverter Class Reference

Public Member Functions
	__construct ($output_precision=4, $internal_precision=10, $force_no_bcmath=false)
	convert ($length, $to_unit)
	Converts a length object of one unit into another unit.
	getSigFigs ($n)
	Returns the number of significant figures in a string number.

Public Attributes
const	DIGITAL = 3
const	ENGLISH = 1
const	METRIC = 2

Protected Attributes
	$internalPrecision
	Bcmath precision for internal calculations.
	$outputPrecision
	Minimum bcmath precision for output.

Static Protected Attributes
static	$units
	Units information array.

Member Function Documentation

convert()

HTMLPurifier_UnitConverter::convert	(		$length,
			$to_unit )

Converts a length object of one unit into another unit.

Parameters

HTMLPurifier_Length	$length	Instance of HTMLPurifier_Length to convert. You must validate() it before passing it here!
string	$to_unit	Unit to convert to.

Return values

HTMLPurifier_Length|bool

Note

About precision: This conversion function pays very special attention to the incoming precision of values and attempts to maintain a number of significant figure. Results are fairly accurate up to nine digits. Some caveats:

• If a number is zero-padded as a result of this significant figure tracking, the zeroes will be eliminated.
• If a number contains less than four sigfigs ($outputPrecision) and this causes some decimals to be excluded, those decimals will be added on.

getSigFigs()

HTMLPurifier_UnitConverter::getSigFigs

(

$n

)

Returns the number of significant figures in a string number.

Parameters

string

$n

Decimal number

Return values

int	number of sigfigs

Member Data Documentation

$internalPrecision

HTMLPurifier_UnitConverter::$internalPrecision

protected

Bcmath precision for internal calculations.

@type int

$outputPrecision

HTMLPurifier_UnitConverter::$outputPrecision

protected

Minimum bcmath precision for output.

@type int

$units

HTMLPurifier_UnitConverter::$units

staticprotected

Initial value:

= array(
        self::ENGLISH => array(
            'px' => 3, 
            'pt' => 4,
            'pc' => 48,
            'in' => 288,
            self::METRIC => array('pt', '0.352777778', 'mm'),
        ),
        self::METRIC => array(
            'mm' => 1,
            'cm' => 10,
            self::ENGLISH => array('mm', '2.83464567', 'pt'),
        ),
    )

Units information array.

Units are grouped into measuring systems (English, Metric), and are assigned an integer representing the conversion factor between that unit and the smallest unit in the system. Numeric indexes are actually magical constants that encode conversion data from one system to the next, with a O(n^2) constraint on memory (this is generally not a problem, since the number of measuring systems is small.)

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The documentation for this class was generated from the following file:

• lib/htmlpurifier/HTMLPurifier/UnitConverter.php