/**
  * @dataProvider isXhtmlLengthProvider
  * 
  * @param mixed $input
  * @param boolean $expected
  */
 public function testIsXhtmlLength($input, $expected)
 {
     $this->assertSame($expected, Format::isXhtmlLength($input));
 }
 /**
  * Set the width attribute. A negative (< 0) value for $width means there
  * is no width indicated.
  * 
  * @param integer $width An integer (pixels) or a string (percentage).
  * @throws InvalidArgumentException If $width is not an integer value.
  */
 public function setWidth($width)
 {
     if (is_int($width) && $width === -1 || Format::isXhtmlLength($width) === true) {
         $this->width = $width;
     } else {
         $msg = "The 'width' argument must be a valid XHTML length value, '" . $width . "' given.";
         throw new InvalidArgumentException($msg);
     }
 }