/** * @inheritdoc */ public function convertUnitOfMeasure($measurement, $startUnit, $resultUnit, $round = true) { if ($startUnit === self::DOTS_PER_INCH) { switch ($resultUnit) { case self::DOTS_PER_CENTIMETER: $measurement *= 2.54; break; } } elseif ($startUnit === self::DOTS_PER_CENTIMETER) { switch ($resultUnit) { case self::DOTS_PER_INCH: $measurement /= 2.54; break; } } elseif ($startUnit === self::UNIT_INCHES) { switch ($resultUnit) { case self::DOTS_PER_INCH: $measurement *= $this->dpi; break; case self::DOTS_PER_CENTIMETER: $measurement *= 2.54 * $this->dpi; break; } } return parent::convertUnitOfMeasure($measurement, $startUnit, $resultUnit, $round); }