diff core/lib/Drupal/Component/Utility/Rectangle.php @ 0:4c8ae668cc8c

Initial import (non-working)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/lib/Drupal/Component/Utility/Rectangle.php	Wed Nov 29 16:09:58 2017 +0000
@@ -0,0 +1,195 @@
+<?php
+
+namespace Drupal\Component\Utility;
+
+/**
+ * Rectangle rotation algebra class.
+ *
+ * This class is used by the image system to abstract, from toolkit
+ * implementations, the calculation of the expected dimensions resulting from
+ * an image rotate operation.
+ *
+ * Different versions of PHP for the GD toolkit, and alternative toolkits, use
+ * different algorithms to perform the rotation of an image and result in
+ * different dimensions of the output image. This prevents predictability of
+ * the final image size for instance by the image rotate effect, or by image
+ * toolkit rotate operations.
+ *
+ * This class implements a calculation algorithm that returns, given input
+ * width, height and rotation angle, dimensions of the expected image after
+ * rotation that are consistent with those produced by the GD rotate image
+ * toolkit operation using PHP 5.5 and above.
+ *
+ * @see \Drupal\system\Plugin\ImageToolkit\Operation\gd\Rotate
+ */
+class Rectangle {
+
+  /**
+   * The width of the rectangle.
+   *
+   * @var int
+   */
+  protected $width;
+
+  /**
+   * The height of the rectangle.
+   *
+   * @var int
+   */
+  protected $height;
+
+  /**
+   * The width of the rotated rectangle.
+   *
+   * @var int
+   */
+  protected $boundingWidth;
+
+  /**
+   * The height of the rotated rectangle.
+   *
+   * @var int
+   */
+  protected $boundingHeight;
+
+  /**
+   * Constructs a new Rectangle object.
+   *
+   * @param int $width
+   *   The width of the rectangle.
+   * @param int $height
+   *   The height of the rectangle.
+   */
+  public function __construct($width, $height) {
+    if ($width > 0 && $height > 0) {
+      $this->width = $width;
+      $this->height = $height;
+      $this->boundingWidth = $width;
+      $this->boundingHeight = $height;
+    }
+    else {
+      throw new \InvalidArgumentException("Invalid dimensions ({$width}x{$height}) specified for a Rectangle object");
+    }
+  }
+
+  /**
+   * Rotates the rectangle.
+   *
+   * @param float $angle
+   *   Rotation angle.
+   *
+   * @return $this
+   */
+  public function rotate($angle) {
+    // PHP 5.5 GD bug: https://bugs.php.net/bug.php?id=65148: To prevent buggy
+    // behavior on negative multiples of 30 degrees we convert any negative
+    // angle to a positive one between 0 and 360 degrees.
+    $angle -= floor($angle / 360) * 360;
+
+    // For some rotations that are multiple of 30 degrees, we need to correct
+    // an imprecision between GD that uses C floats internally, and PHP that
+    // uses C doubles. Also, for rotations that are not multiple of 90 degrees,
+    // we need to introduce a correction factor of 0.5 to match the GD
+    // algorithm used in PHP 5.5 (and above) to calculate the width and height
+    // of the rotated image.
+    if ((int) $angle == $angle && $angle % 90 == 0) {
+      $imprecision = 0;
+      $correction = 0;
+    }
+    else {
+      $imprecision = -0.00001;
+      $correction = 0.5;
+    }
+
+    // Do the trigonometry, applying imprecision fixes where needed.
+    $rad = deg2rad($angle);
+    $cos = cos($rad);
+    $sin = sin($rad);
+    $a = $this->width * $cos;
+    $b = $this->height * $sin + $correction;
+    $c = $this->width * $sin;
+    $d = $this->height * $cos + $correction;
+    if ((int) $angle == $angle && in_array($angle, [60, 150, 300])) {
+      $a = $this->fixImprecision($a, $imprecision);
+      $b = $this->fixImprecision($b, $imprecision);
+      $c = $this->fixImprecision($c, $imprecision);
+      $d = $this->fixImprecision($d, $imprecision);
+    }
+
+    // This is how GD on PHP5.5 calculates the new dimensions.
+    $this->boundingWidth = abs((int) $a) + abs((int) $b);
+    $this->boundingHeight = abs((int) $c) + abs((int) $d);
+
+    return $this;
+  }
+
+  /**
+   * Performs an imprecision check on the input value and fixes it if needed.
+   *
+   * GD that uses C floats internally, whereas we at PHP level use C doubles.
+   * In some cases, we need to compensate imprecision.
+   *
+   * @param float $input
+   *   The input value.
+   * @param float $imprecision
+   *   The imprecision factor.
+   *
+   * @return float
+   *   A value, where imprecision is added to input if the delta part of the
+   *   input is lower than the absolute imprecision.
+   */
+  protected function fixImprecision($input, $imprecision) {
+    if ($this->delta($input) < abs($imprecision)) {
+      return $input + $imprecision;
+    }
+    return $input;
+  }
+
+  /**
+   * Returns the fractional part of a float number, unsigned.
+   *
+   * @param float $input
+   *   The input value.
+   *
+   * @return float
+   *   The fractional part of the input number, unsigned.
+   */
+  protected function fraction($input) {
+    return abs((int) $input - $input);
+  }
+
+  /**
+   * Returns the difference of a fraction from the closest between 0 and 1.
+   *
+   * @param float $input
+   *   The input value.
+   *
+   * @return float
+   *   the difference of a fraction from the closest between 0 and 1.
+   */
+  protected function delta($input) {
+    $fraction = $this->fraction($input);
+    return $fraction > 0.5 ? (1 - $fraction) : $fraction;
+  }
+
+  /**
+   * Gets the bounding width of the rectangle.
+   *
+   * @return int
+   *   The bounding width of the rotated rectangle.
+   */
+  public function getBoundingWidth() {
+    return $this->boundingWidth;
+  }
+
+  /**
+   * Gets the bounding height of the rectangle.
+   *
+   * @return int
+   *   The bounding height of the rotated rectangle.
+   */
+  public function getBoundingHeight() {
+    return $this->boundingHeight;
+  }
+
+}