Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Component\Utility;
Chris@0: 
Chris@0: /**
Chris@0:  * Rectangle rotation algebra class.
Chris@0:  *
Chris@0:  * This class is used by the image system to abstract, from toolkit
Chris@0:  * implementations, the calculation of the expected dimensions resulting from
Chris@0:  * an image rotate operation.
Chris@0:  *
Chris@0:  * Different versions of PHP for the GD toolkit, and alternative toolkits, use
Chris@0:  * different algorithms to perform the rotation of an image and result in
Chris@0:  * different dimensions of the output image. This prevents predictability of
Chris@0:  * the final image size for instance by the image rotate effect, or by image
Chris@0:  * toolkit rotate operations.
Chris@0:  *
Chris@0:  * This class implements a calculation algorithm that returns, given input
Chris@0:  * width, height and rotation angle, dimensions of the expected image after
Chris@0:  * rotation that are consistent with those produced by the GD rotate image
Chris@0:  * toolkit operation using PHP 5.5 and above.
Chris@0:  *
Chris@0:  * @see \Drupal\system\Plugin\ImageToolkit\Operation\gd\Rotate
Chris@0:  */
Chris@0: class Rectangle {
Chris@0: 
Chris@0:   /**
Chris@0:    * The width of the rectangle.
Chris@0:    *
Chris@0:    * @var int
Chris@0:    */
Chris@0:   protected $width;
Chris@0: 
Chris@0:   /**
Chris@0:    * The height of the rectangle.
Chris@0:    *
Chris@0:    * @var int
Chris@0:    */
Chris@0:   protected $height;
Chris@0: 
Chris@0:   /**
Chris@0:    * The width of the rotated rectangle.
Chris@0:    *
Chris@0:    * @var int
Chris@0:    */
Chris@0:   protected $boundingWidth;
Chris@0: 
Chris@0:   /**
Chris@0:    * The height of the rotated rectangle.
Chris@0:    *
Chris@0:    * @var int
Chris@0:    */
Chris@0:   protected $boundingHeight;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a new Rectangle object.
Chris@0:    *
Chris@0:    * @param int $width
Chris@0:    *   The width of the rectangle.
Chris@0:    * @param int $height
Chris@0:    *   The height of the rectangle.
Chris@0:    */
Chris@0:   public function __construct($width, $height) {
Chris@0:     if ($width > 0 && $height > 0) {
Chris@0:       $this->width = $width;
Chris@0:       $this->height = $height;
Chris@0:       $this->boundingWidth = $width;
Chris@0:       $this->boundingHeight = $height;
Chris@0:     }
Chris@0:     else {
Chris@0:       throw new \InvalidArgumentException("Invalid dimensions ({$width}x{$height}) specified for a Rectangle object");
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Rotates the rectangle.
Chris@0:    *
Chris@0:    * @param float $angle
Chris@0:    *   Rotation angle.
Chris@0:    *
Chris@0:    * @return $this
Chris@0:    */
Chris@0:   public function rotate($angle) {
Chris@0:     // PHP 5.5 GD bug: https://bugs.php.net/bug.php?id=65148: To prevent buggy
Chris@0:     // behavior on negative multiples of 30 degrees we convert any negative
Chris@0:     // angle to a positive one between 0 and 360 degrees.
Chris@0:     $angle -= floor($angle / 360) * 360;
Chris@0: 
Chris@0:     // For some rotations that are multiple of 30 degrees, we need to correct
Chris@0:     // an imprecision between GD that uses C floats internally, and PHP that
Chris@0:     // uses C doubles. Also, for rotations that are not multiple of 90 degrees,
Chris@0:     // we need to introduce a correction factor of 0.5 to match the GD
Chris@0:     // algorithm used in PHP 5.5 (and above) to calculate the width and height
Chris@0:     // of the rotated image.
Chris@0:     if ((int) $angle == $angle && $angle % 90 == 0) {
Chris@0:       $imprecision = 0;
Chris@0:       $correction = 0;
Chris@0:     }
Chris@0:     else {
Chris@0:       $imprecision = -0.00001;
Chris@0:       $correction = 0.5;
Chris@0:     }
Chris@0: 
Chris@0:     // Do the trigonometry, applying imprecision fixes where needed.
Chris@0:     $rad = deg2rad($angle);
Chris@0:     $cos = cos($rad);
Chris@0:     $sin = sin($rad);
Chris@0:     $a = $this->width * $cos;
Chris@0:     $b = $this->height * $sin + $correction;
Chris@0:     $c = $this->width * $sin;
Chris@0:     $d = $this->height * $cos + $correction;
Chris@0:     if ((int) $angle == $angle && in_array($angle, [60, 150, 300])) {
Chris@0:       $a = $this->fixImprecision($a, $imprecision);
Chris@0:       $b = $this->fixImprecision($b, $imprecision);
Chris@0:       $c = $this->fixImprecision($c, $imprecision);
Chris@0:       $d = $this->fixImprecision($d, $imprecision);
Chris@0:     }
Chris@0: 
Chris@0:     // This is how GD on PHP5.5 calculates the new dimensions.
Chris@0:     $this->boundingWidth = abs((int) $a) + abs((int) $b);
Chris@0:     $this->boundingHeight = abs((int) $c) + abs((int) $d);
Chris@0: 
Chris@0:     return $this;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Performs an imprecision check on the input value and fixes it if needed.
Chris@0:    *
Chris@0:    * GD that uses C floats internally, whereas we at PHP level use C doubles.
Chris@0:    * In some cases, we need to compensate imprecision.
Chris@0:    *
Chris@0:    * @param float $input
Chris@0:    *   The input value.
Chris@0:    * @param float $imprecision
Chris@0:    *   The imprecision factor.
Chris@0:    *
Chris@0:    * @return float
Chris@0:    *   A value, where imprecision is added to input if the delta part of the
Chris@0:    *   input is lower than the absolute imprecision.
Chris@0:    */
Chris@0:   protected function fixImprecision($input, $imprecision) {
Chris@0:     if ($this->delta($input) < abs($imprecision)) {
Chris@0:       return $input + $imprecision;
Chris@0:     }
Chris@0:     return $input;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the fractional part of a float number, unsigned.
Chris@0:    *
Chris@0:    * @param float $input
Chris@0:    *   The input value.
Chris@0:    *
Chris@0:    * @return float
Chris@0:    *   The fractional part of the input number, unsigned.
Chris@0:    */
Chris@0:   protected function fraction($input) {
Chris@0:     return abs((int) $input - $input);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the difference of a fraction from the closest between 0 and 1.
Chris@0:    *
Chris@0:    * @param float $input
Chris@0:    *   The input value.
Chris@0:    *
Chris@0:    * @return float
Chris@0:    *   the difference of a fraction from the closest between 0 and 1.
Chris@0:    */
Chris@0:   protected function delta($input) {
Chris@0:     $fraction = $this->fraction($input);
Chris@0:     return $fraction > 0.5 ? (1 - $fraction) : $fraction;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Gets the bounding width of the rectangle.
Chris@0:    *
Chris@0:    * @return int
Chris@0:    *   The bounding width of the rotated rectangle.
Chris@0:    */
Chris@0:   public function getBoundingWidth() {
Chris@0:     return $this->boundingWidth;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Gets the bounding height of the rectangle.
Chris@0:    *
Chris@0:    * @return int
Chris@0:    *   The bounding height of the rotated rectangle.
Chris@0:    */
Chris@0:   public function getBoundingHeight() {
Chris@0:     return $this->boundingHeight;
Chris@0:   }
Chris@0: 
Chris@0: }