389 lines
12 KiB
PHP
389 lines
12 KiB
PHP
<?php
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// $Id$
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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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* 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 ImageMagic 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/settings/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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* Return 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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* Retrieve 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]) || !drupal_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 $params
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* An optional array of parameters to pass to the toolkit method.
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* @return
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* Mixed values (typically Boolean indicating successful operation).
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*/
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function image_toolkit_invoke($method, stdClass $image, array $params = array()) {
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$function = 'image_' . $image->toolkit . '_' . $method;
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if (drupal_function_exists($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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* Get details about an image.
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*
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* Drupal only supports GIF, JPG and PNG file formats.
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*
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* @param $filepath
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* String specifying the path of the image file.
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* @return
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* FALSE, if the file could not be found or is not an image. Otherwise, a
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* keyed array containing information about the image:
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* 'width' - Width, in pixels.
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* 'height' - Height, in pixels.
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* 'extension' - Commonly used file extension for the image.
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* 'mime_type' - MIME type ('image/jpeg', 'image/gif', 'image/png').
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* 'file_size' - File size in bytes.
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*/
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function image_get_info($filepath) {
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if (!is_file($filepath)) {
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return FALSE;
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}
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$details = FALSE;
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$data = @getimagesize($filepath);
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$file_size = @filesize($filepath);
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if (isset($data) && is_array($data)) {
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$extensions = array('1' => 'gif', '2' => 'jpg', '3' => 'png');
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$extension = array_key_exists($data[2], $extensions) ? $extensions[$data[2]] : '';
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$details = array('width' => $data[0],
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'height' => $data[1],
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'extension' => $extension,
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'file_size' => $file_size,
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'mime_type' => $data['mime']);
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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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* @return
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* TRUE or FALSE, based on success.
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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 an image to the given width and height 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. This value is omitted then the scaling will
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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. This value is omitted then the scaling will
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* 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 scalled
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* up. This generally results in a low quality image.
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* @return
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* TRUE or FALSE, based on success.
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*
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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, $upscale = FALSE) {
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$aspect = $image->info['height'] / $image->info['width'];
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if ($upscale) {
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// Set width/height according to aspect ratio if either is empty.
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$width = !empty($width) ? $width : $height / $aspect;
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$height = !empty($height) ? $height : $width / $aspect;
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}
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else {
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// Set impossibly large values if the width and height aren't set.
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$width = !empty($width) ? $width : 9999999;
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$height = !empty($height) ? $height : 9999999;
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// Don't scale up.
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if (round($width) >= $image->info['width'] && round($height) >= $image->info['height']) {
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return TRUE;
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}
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}
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if ($aspect < $height / $width) {
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$height = $width * $aspect;
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}
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else {
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$width = $height / $aspect;
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}
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return image_resize($image, $width, $height);
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}
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/**
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* Resize 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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* @return
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* TRUE or FALSE, based on success.
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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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* Rotate 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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* @return
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* TRUE or FALSE, based on success.
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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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* Crop an image to the rectangle specified by the given rectangle.
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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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* @return
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* TRUE or FALSE, based on success.
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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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* Convert 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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* @return
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* TRUE or FALSE, based on success.
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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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* Load an image file and return 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 $toolkit
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* An optional, image toolkit name to override the default.
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* @return
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* An image object or FALSE if there was a problem loading the file. The
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* image object has the following properties:
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* - 'source' - The original file path.
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* - 'info' - The array of information returned by image_get_info()
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* - 'toolkit' - The name of the image toolkit requested when the image was
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* loaded.
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* Image tookits may add additional properties. The caller is advised not to
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* monkey about with them.
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*
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* @see image_save()
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* @see image_get_info()
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* @see image_get_available_toolkits()
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* @see image_gd_load()
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*/
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function image_load($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($file);
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$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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return FALSE;
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}
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/**
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* Close the image and save 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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* @return
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* TRUE or FALSE, based on success.
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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);
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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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