Rotate an image the given number of degrees.

Parameters

$image: An image object. The $image->resource, $image->info['width'], and $image->info['height'] values will be modified by this call.

$degrees: The number of (clockwise) degrees to rotate the image.

$background: An hexadecimal integer specifying the background color to use for the uncovered area of the image after the rotation. E.g. 0x000000 for black, 0xff00ff for magenta, and 0xffffff for white. For images that support transparency, this will default to transparent. Otherwise it will be white.

Return value

TRUE or FALSE, based on success.

See also

image_rotate()

Related topics

File

drupal-7.x/modules/system/image.gd.inc, line 117

GD2 toolkit for image manipulation within Drupal.

Code

function image_gd_rotate(stdClass $image, $degrees, $background = NULL) {
  // PHP installations using non-bundled GD do not have imagerotate.
  if (!function_exists('imagerotate')) {
    watchdog('image', 'The image %file could not be rotated because the imagerotate() function is not available in this PHP installation.', array('%file' => $image->source));
    return FALSE;
  }

  $width = $image->info['width'];
  $height = $image->info['height'];

  // Convert the hexadecimal background value to a color index value.
  if (isset($background)) {
    $rgb = array();
    for ($i = 16; $i >= 0; $i -= 8) {
      $rgb[] = (($background >> $i) & 0xFF);
    }
    $background = imagecolorallocatealpha($image->resource, $rgb[0], $rgb[1], $rgb[2], 0);
  }
  // Set the background color as transparent if $background is NULL.
  else {
    // Get the current transparent color.
    $background = imagecolortransparent($image->resource);

    // If no transparent colors, use white.
    if ($background == 0) {
      $background = imagecolorallocatealpha($image->resource, 255, 255, 255, 0);
    }
  }

  // Images are assigned a new color palette when rotating, removing any
  // transparency flags. For GIF images, keep a record of the transparent color.
  if ($image->info['extension'] == 'gif') {
    $transparent_index = imagecolortransparent($image->resource);
    if ($transparent_index != 0) {
      $transparent_gif_color = imagecolorsforindex($image->resource, $transparent_index);
    }
  }

  $image->resource = imagerotate($image->resource, 360 - $degrees, $background);

  // GIFs need to reassign the transparent color after performing the rotate.
  if (isset($transparent_gif_color)) {
    $background = imagecolorexactalpha($image->resource, $transparent_gif_color['red'], $transparent_gif_color['green'], $transparent_gif_color['blue'], $transparent_gif_color['alpha']);
    imagecolortransparent($image->resource, $background);
  }

  $image->info['width'] = imagesx($image->resource);
  $image->info['height'] = imagesy($image->resource);
  return TRUE;
}