436 lines
13 KiB
PHP
436 lines
13 KiB
PHP
<?php
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/**
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* @file
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* API for manipulating images.
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*/
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/**
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* @defgroup image Image toolkits
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* @{
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* Functions for image file manipulations.
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*
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* Drupal's image toolkits provide an abstraction layer for common image file
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* manipulations like scaling, cropping, and rotating. The abstraction frees
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* module authors from the need to support multiple image libraries, and it
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* allows site administrators to choose the library that's best for them.
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*
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* PHP includes the GD library by default so a GD toolkit is installed with
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* Drupal. Other toolkits like ImageMagick are available from contrib modules.
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* GD works well for small images, but using it with larger files may cause PHP
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* to run out of memory. In contrast the ImageMagick library does not suffer
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* from this problem, but it requires the ISP to have installed additional
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* software.
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*
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* Image toolkits are discovered based on the associated module's
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* hook_image_toolkits. Additionally the image toolkit include file
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* must be identified in the files array in the module.info file. The
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* toolkit must then be enabled using the admin/config/media/image-toolkit
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* form.
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*
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* Only one toolkit may be selected at a time. If a module author wishes to call
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* a specific toolkit they can check that it is installed by calling
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* image_get_available_toolkits(), and then calling its functions directly.
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*/
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/**
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* Gets a list of available toolkits.
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*
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* @return
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* An array with the toolkit names as keys and the descriptions as values.
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*/
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function image_get_available_toolkits() {
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// hook_image_toolkits returns an array of toolkit names.
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$toolkits = module_invoke_all('image_toolkits');
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$output = array();
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foreach ($toolkits as $name => $info) {
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// Only allow modules that aren't marked as unavailable.
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if ($info['available']) {
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$output[$name] = $info['title'];
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}
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}
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return $output;
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}
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/**
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* Gets the name of the currently used toolkit.
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*
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* @return
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* String containing the name of the selected toolkit, or FALSE on error.
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*/
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function image_get_toolkit() {
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static $toolkit;
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if (!isset($toolkit)) {
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$toolkits = image_get_available_toolkits();
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$toolkit = variable_get('image_toolkit', 'gd');
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if (!isset($toolkits[$toolkit]) || !function_exists('image_' . $toolkit . '_load')) {
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// The selected toolkit isn't available so return the first one found. If
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// none are available this will return FALSE.
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reset($toolkits);
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$toolkit = key($toolkits);
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}
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}
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return $toolkit;
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}
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/**
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* Invokes the given method using the currently selected toolkit.
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*
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* @param $method
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* A string containing the method to invoke.
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* @param $image
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* An image object returned by image_load().
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* @param $params
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* An optional array of parameters to pass to the toolkit method.
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*
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* @return
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* Mixed values (typically Boolean indicating successful operation).
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*/
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function image_toolkit_invoke($method, stdClass $image, array $params = array()) {
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$function = 'image_' . $image->toolkit . '_' . $method;
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if (function_exists($function)) {
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array_unshift($params, $image);
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return call_user_func_array($function, $params);
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}
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watchdog('image', 'The selected image handling toolkit %toolkit can not correctly process %function.', array('%toolkit' => $image->toolkit, '%function' => $function), WATCHDOG_ERROR);
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return FALSE;
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}
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/**
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* Gets details about an image.
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*
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* Drupal supports GIF, JPG and PNG file formats when used with the GD
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* toolkit, and may support others, depending on which toolkits are
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* installed.
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*
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* @param $filepath
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* String specifying the path of the image file.
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* @param $toolkit
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* An optional image toolkit name to override the default.
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*
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* @return
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* FALSE, if the file could not be found or is not an image. Otherwise, a
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* keyed array containing information about the image:
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* - "width": Width, in pixels.
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* - "height": Height, in pixels.
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* - "extension": Commonly used file extension for the image.
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* - "mime_type": MIME type ('image/jpeg', 'image/gif', 'image/png').
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* - "file_size": File size in bytes.
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*/
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function image_get_info($filepath, $toolkit = FALSE) {
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$details = FALSE;
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if (!is_file($filepath) && !is_uploaded_file($filepath)) {
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return $details;
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}
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if (!$toolkit) {
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$toolkit = image_get_toolkit();
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}
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if ($toolkit) {
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$image = new stdClass();
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$image->source = $filepath;
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$image->toolkit = $toolkit;
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$details = image_toolkit_invoke('get_info', $image);
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if (isset($details) && is_array($details)) {
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$details['file_size'] = filesize($filepath);
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}
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}
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return $details;
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}
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/**
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* Scales an image to the exact width and height given.
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*
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* This function achieves the target aspect ratio by cropping the original image
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* equally on both sides, or equally on the top and bottom. This function is
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* useful to create uniform sized avatars from larger images.
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*
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* The resulting image always has the exact target dimensions.
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*
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* @param $image
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* An image object returned by image_load().
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* @param $width
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* The target width, in pixels.
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* @param $height
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* The target height, in pixels.
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*
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* @return
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* TRUE on success, FALSE on failure.
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*
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* @see image_load()
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* @see image_resize()
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* @see image_crop()
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*/
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function image_scale_and_crop(stdClass $image, $width, $height) {
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$scale = max($width / $image->info['width'], $height / $image->info['height']);
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$x = ($image->info['width'] * $scale - $width) / 2;
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$y = ($image->info['height'] * $scale - $height) / 2;
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if (image_resize($image, $image->info['width'] * $scale, $image->info['height'] * $scale)) {
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return image_crop($image, $x, $y, $width, $height);
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}
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return FALSE;
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}
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/**
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* Scales image dimensions while maintaining aspect ratio.
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*
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* The resulting dimensions can be smaller for one or both target dimensions.
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*
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* @param $dimensions
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* Dimensions to be modified - an array with components width and height, in
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* pixels.
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* @param $width
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* The target width, in pixels. If this value is NULL then the scaling will be
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* based only on the height value.
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* @param $height
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* The target height, in pixels. If this value is NULL then the scaling will
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* be based only on the width value.
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* @param $upscale
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* Boolean indicating that images smaller than the target dimensions will be
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* scaled up. This generally results in a low quality image.
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*
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* @return
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* TRUE if $dimensions was modified, FALSE otherwise.
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*
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* @see image_scale()
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*/
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function image_dimensions_scale(array &$dimensions, $width = NULL, $height = NULL, $upscale = FALSE) {
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$aspect = $dimensions['height'] / $dimensions['width'];
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// Calculate one of the dimensions from the other target dimension,
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// ensuring the same aspect ratio as the source dimensions. If one of the
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// target dimensions is missing, that is the one that is calculated. If both
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// are specified then the dimension calculated is the one that would not be
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// calculated to be bigger than its target.
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if (($width && !$height) || ($width && $height && $aspect < $height / $width)) {
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$height = (int) round($width * $aspect);
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}
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else {
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$width = (int) round($height / $aspect);
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}
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// Don't upscale if the option isn't enabled.
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if (!$upscale && ($width >= $dimensions['width'] || $height >= $dimensions['height'])) {
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return FALSE;
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}
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$dimensions['width'] = $width;
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$dimensions['height'] = $height;
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return TRUE;
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}
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/**
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* Scales an image while maintaining aspect ratio.
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*
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* The resulting image can be smaller for one or both target dimensions.
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*
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* @param $image
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* An image object returned by image_load().
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* @param $width
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* The target width, in pixels. If this value is NULL then the scaling will
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* be based only on the height value.
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* @param $height
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* The target height, in pixels. If this value is NULL then the scaling will
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* be based only on the width value.
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* @param $upscale
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* Boolean indicating that files smaller than the dimensions will be scaled
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* up. This generally results in a low quality image.
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*
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* @return
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* TRUE on success, FALSE on failure.
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*
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* @see image_dimensions_scale()
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* @see image_load()
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* @see image_scale_and_crop()
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*/
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function image_scale(stdClass $image, $width = NULL, $height = NULL, $upscale = FALSE) {
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$dimensions = $image->info;
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// Scale the dimensions - if they don't change then just return success.
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if (!image_dimensions_scale($dimensions, $width, $height, $upscale)) {
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return TRUE;
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}
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return image_resize($image, $dimensions['width'], $dimensions['height']);
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}
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/**
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* Resizes an image to the given dimensions (ignoring aspect ratio).
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*
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* @param $image
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* An image object returned by image_load().
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* @param $width
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* The target width, in pixels.
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* @param $height
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* The target height, in pixels.
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*
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* @return
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* TRUE on success, FALSE on failure.
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*
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* @see image_load()
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* @see image_gd_resize()
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*/
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function image_resize(stdClass $image, $width, $height) {
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$width = (int) round($width);
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$height = (int) round($height);
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return image_toolkit_invoke('resize', $image, array($width, $height));
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}
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/**
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* Rotates an image by the given number of degrees.
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*
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* @param $image
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* An image object returned by image_load().
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* @param $degrees
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* The number of (clockwise) degrees to rotate the image.
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* @param $background
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* An hexadecimal integer specifying the background color to use for the
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* uncovered area of the image after the rotation. E.g. 0x000000 for black,
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* 0xff00ff for magenta, and 0xffffff for white. For images that support
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* transparency, this will default to transparent. Otherwise it will
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* be white.
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*
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* @return
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* TRUE on success, FALSE on failure.
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*
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* @see image_load()
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* @see image_gd_rotate()
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*/
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function image_rotate(stdClass $image, $degrees, $background = NULL) {
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return image_toolkit_invoke('rotate', $image, array($degrees, $background));
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}
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/**
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* Crops an image to a rectangle specified by the given dimensions.
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*
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* @param $image
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* An image object returned by image_load().
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* @param $x
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* The top left coordinate, in pixels, of the crop area (x axis value).
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* @param $y
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* The top left coordinate, in pixels, of the crop area (y axis value).
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* @param $width
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* The target width, in pixels.
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* @param $height
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* The target height, in pixels.
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*
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* @return
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* TRUE on success, FALSE on failure.
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*
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* @see image_load()
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* @see image_scale_and_crop()
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* @see image_gd_crop()
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*/
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function image_crop(stdClass $image, $x, $y, $width, $height) {
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$aspect = $image->info['height'] / $image->info['width'];
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if (empty($height)) $height = $width / $aspect;
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if (empty($width)) $width = $height * $aspect;
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$width = (int) round($width);
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$height = (int) round($height);
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return image_toolkit_invoke('crop', $image, array($x, $y, $width, $height));
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}
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/**
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* Converts an image to grayscale.
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*
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* @param $image
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* An image object returned by image_load().
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*
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* @return
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* TRUE on success, FALSE on failure.
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*
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* @see image_load()
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* @see image_gd_desaturate()
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*/
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function image_desaturate(stdClass $image) {
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return image_toolkit_invoke('desaturate', $image);
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}
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/**
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* Loads an image file and returns an image object.
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*
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* Any changes to the file are not saved until image_save() is called.
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*
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* @param $file
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* Path to an image file.
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* @param $toolkit
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* An optional, image toolkit name to override the default.
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*
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* @return
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* An image object or FALSE if there was a problem loading the file. The
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* image object has the following properties:
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* - 'source' - The original file path.
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* - 'info' - The array of information returned by image_get_info()
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* - 'toolkit' - The name of the image toolkit requested when the image was
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* loaded.
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* Image toolkits may add additional properties. The caller is advised not to
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* monkey about with them.
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*
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* @see image_save()
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* @see image_get_info()
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* @see image_get_available_toolkits()
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* @see image_gd_load()
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*/
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function image_load($file, $toolkit = FALSE) {
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if (!$toolkit) {
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$toolkit = image_get_toolkit();
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}
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if ($toolkit) {
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$image = new stdClass();
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$image->source = $file;
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$image->info = image_get_info($file, $toolkit);
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if (isset($image->info) && is_array($image->info)) {
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$image->toolkit = $toolkit;
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if (image_toolkit_invoke('load', $image)) {
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return $image;
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}
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}
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}
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return FALSE;
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}
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/**
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* Closes the image and saves the changes to a file.
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*
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* @param $image
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* An image object returned by image_load(). The object's 'info' property
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* will be updated if the file is saved successfully.
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* @param $destination
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* Destination path where the image should be saved. If it is empty the
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* original image file will be overwritten.
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*
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* @return
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* TRUE on success, FALSE on failure.
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*
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* @see image_load()
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* @see image_gd_save()
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*/
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function image_save(stdClass $image, $destination = NULL) {
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if (empty($destination)) {
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$destination = $image->source;
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}
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if ($return = image_toolkit_invoke('save', $image, array($destination))) {
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// Clear the cached file size and refresh the image information.
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clearstatcache();
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$image->info = image_get_info($destination, $image->toolkit);
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if (drupal_chmod($destination)) {
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return $return;
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}
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}
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return FALSE;
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}
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/**
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* @} End of "defgroup image".
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*/
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