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<?php
// $Id$
/**
* @file
* API for manipulating images.
*/
/**
* @defgroup image Image toolkits
* @{
* Drupal's image toolkits provide an abstraction layer for common image file
* manipulations like scaling, cropping, and rotating. The abstraction frees
* module authors from the need to support multiple image libraries, and it
* allows site administrators to choose the library that's best for them.
*
* PHP includes the GD library by default so a GD toolkit is installed with
* Drupal. Other toolkits like ImageMagic are available from contrib modules.
* GD works well for small images, but using it with larger files may cause PHP
* to run out of memory. In contrast the ImageMagick library does not suffer
* from this problem, but it requires the ISP to have installed additional
* software.
*
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* Image toolkits are discovered based on the associated module's
* 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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* Only one toolkit may be selected at a time. If a module author wishes to call
* a specific toolkit they can check that it is installed by calling
* image_get_available_toolkits(), and then calling its functions directly.
*/
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/**
* Return a list of available toolkits.
*
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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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*/
function image_get_available_toolkits() {
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// hook_image_toolkits returns an array of toolkit names.
$toolkits = module_invoke_all('image_toolkits');
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$output = array();
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foreach ($toolkits as $name => $info) {
// Only allow modules that aren't marked as unavailable.
if ($info['available']) {
$output[$name] = $info['title'];
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}
}
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return $output;
}
/**
* Retrieve the name of the currently used toolkit.
*
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* @return
* String containing the name of the selected toolkit, or FALSE on error.
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*/
function image_get_toolkit() {
static $toolkit;
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if (!isset($toolkit)) {
$toolkits = image_get_available_toolkits();
$toolkit = variable_get('image_toolkit', 'gd');
if (!isset($toolkits[$toolkit]) || !function_exists('image_' . $toolkit . '_load')) {
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// The selected toolkit isn't available so return the first one found. If
// none are available this will return FALSE.
reset($toolkits);
$toolkit = key($toolkits);
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}
}
return $toolkit;
}
/**
* Invokes the given method using the currently selected toolkit.
*
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* @param $method
* A string containing the method to invoke.
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* @param $image
* An image object returned by image_load().
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* @param $params
* An optional array of parameters to pass to the toolkit method.
* @return
* Mixed values (typically Boolean indicating successful operation).
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*/
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function image_toolkit_invoke($method, stdClass $image, array $params = array()) {
$function = 'image_' . $image->toolkit . '_' . $method;
if (function_exists($function)) {
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array_unshift($params, $image);
return call_user_func_array($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);
return FALSE;
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}
/**
* Get details about an image.
*
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* Drupal supports GIF, JPG and PNG file formats when used with the GD
* toolkit, and may support others, depending on which toolkits are
* installed.
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*
* @param $filepath
* String specifying the path of the image file.
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* @param $toolkit
* An optional image toolkit name to override the default.
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* @return
* FALSE, if the file could not be found or is not an image. Otherwise, a
* keyed array containing information about the image:
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* - "width": Width, in pixels.
* - "height": Height, in pixels.
* - "extension": Commonly used file extension for the image.
* - "mime_type": MIME type ('image/jpeg', 'image/gif', 'image/png').
* - "file_size": File size in bytes.
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*/
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function image_get_info($filepath, $toolkit = FALSE) {
$details = FALSE;
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return $details;
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}
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if (!$toolkit) {
$toolkit = image_get_toolkit();
}
if ($toolkit) {
$image = new stdClass();
$image->source = $filepath;
$image->toolkit = $toolkit;
$details = image_toolkit_invoke('get_info', $image);
if (isset($details) && is_array($details)) {
$details['file_size'] = filesize($filepath);
}
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}
return $details;
}
/**
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* Scales an image to the exact width and height given.
*
* This function achieves the target aspect ratio by cropping the original image
* equally on both sides, or equally on the top and bottom. This function is
* useful to create uniform sized avatars from larger images.
*
* The resulting image always has the exact target dimensions.
*
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* @param $image
* An image object returned by image_load().
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* @param $width
* The target width, in pixels.
* @param $height
* The target height, in pixels.
* @return
* TRUE or FALSE, based on success.
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*
* @see image_load()
* @see image_resize()
* @see image_crop()
*/
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function image_scale_and_crop(stdClass $image, $width, $height) {
$scale = max($width / $image->info['width'], $height / $image->info['height']);
$x = ($image->info['width'] * $scale - $width) / 2;
$y = ($image->info['height'] * $scale - $height) / 2;
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if (image_resize($image, $image->info['width'] * $scale, $image->info['height'] * $scale)) {
return image_crop($image, $x, $y, $width, $height);
}
return FALSE;
}
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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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*
* The resulting image can be smaller for one or both target dimensions.
*
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* @param $image
* 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
* 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
* based only on the width value.
* @param $upscale
* Boolean indicating that files smaller than the dimensions will be scalled
* up. This generally results in a low quality image.
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* @return
* TRUE or FALSE, based on success.
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*
* @see image_load()
* @see image_scale_and_crop()
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*/
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function image_scale(stdClass $image, $width = NULL, $height = NULL, $upscale = FALSE) {
$aspect = $image->info['height'] / $image->info['width'];
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if ($upscale) {
// Set width/height according to aspect ratio if either is empty.
$width = !empty($width) ? $width : $height / $aspect;
$height = !empty($height) ? $height : $width / $aspect;
}
else {
// Set impossibly large values if the width and height aren't set.
$width = !empty($width) ? $width : 9999999;
$height = !empty($height) ? $height : 9999999;
// Don't scale up.
if (round($width) >= $image->info['width'] && round($height) >= $image->info['height']) {
return TRUE;
}
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}
if ($aspect < $height / $width) {
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$height = $width * $aspect;
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$width = $height / $aspect;
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}
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return image_resize($image, $width, $height);
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}
/**
* Resize an image to the given dimensions (ignoring aspect ratio).
*
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* @param $image
* An image object returned by image_load().
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* @param $width
* The target width, in pixels.
* @param $height
* The target height, in pixels.
* @return
* TRUE or FALSE, based on success.
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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) {
$width = (int) round($width);
$height = (int) round($height);
return image_toolkit_invoke('resize', $image, array($width, $height));
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}
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/**
* Rotate an image by the given number of degrees.
*
* @param $image
* An image object returned by image_load().
* @param $degrees
* The number of (clockwise) degrees to rotate the image.
* @param $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
* TRUE or FALSE, based on success.
*
* @see image_load()
* @see image_gd_rotate()
*/
function image_rotate(stdClass $image, $degrees, $background = NULL) {
return image_toolkit_invoke('rotate', $image, array($degrees, $background));
}
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/**
* Crop an image to the rectangle specified by the given rectangle.
*
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* @param $image
* 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
* The target width, in pixels.
* @param $height
* The target height, in pixels.
* @return
* TRUE or FALSE, based on success.
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*
* @see image_load()
* @see image_scale_and_crop()
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* @see image_gd_crop()
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*/
function image_crop(stdClass $image, $x, $y, $width, $height) {
$aspect = $image->info['height'] / $image->info['width'];
if (empty($height)) $height = $width / $aspect;
if (empty($width)) $width = $height * $aspect;
$width = (int) round($width);
$height = (int) round($height);
return image_toolkit_invoke('crop', $image, array($x, $y, $width, $height));
}
/**
* Convert an image to grayscale.
*
* @param $image
* An image object returned by image_load().
* @return
* TRUE or FALSE, based on success.
*
* @see image_load()
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* @see image_gd_desaturate()
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*/
function image_desaturate(stdClass $image) {
return image_toolkit_invoke('desaturate', $image);
}
/**
* Load an image file and return an image object.
*
* Any changes to the file are not saved until image_save() is called.
*
* @param $file
* Path to an image file.
* @param $toolkit
* An optional, image toolkit name to override the default.
* @return
* An image object or FALSE if there was a problem loading the file. The
* image object has the following properties:
* - 'source' - The original file path.
* - 'info' - The array of information returned by image_get_info()
* - 'toolkit' - The name of the image toolkit requested when the image was
* loaded.
* Image tookits may add additional properties. The caller is advised not to
* monkey about with them.
*
* @see image_save()
* @see image_get_info()
* @see image_get_available_toolkits()
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* @see image_gd_load()
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*/
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function image_load($file, $toolkit = FALSE) {
if (!$toolkit) {
$toolkit = image_get_toolkit();
}
if ($toolkit) {
$image = new stdClass();
$image->source = $file;
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$image->info = image_get_info($file, $toolkit);
if (isset($image->info) && is_array($image->info)) {
$image->toolkit = $toolkit;
if (image_toolkit_invoke('load', $image)) {
return $image;
}
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}
}
return FALSE;
}
/**
* Close the image and save the changes to a file.
*
* @param $image
* An image object returned by image_load(). The object's 'info' property
* will be updated if the file is saved successfully.
* @param $destination
* Destination path where the image should be saved. If it is empty the
* original image file will be overwritten.
* @return
* TRUE or FALSE, based on success.
*
* @see image_load()
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* @see image_gd_save()
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*/
function image_save(stdClass $image, $destination = NULL) {
if (empty($destination)) {
$destination = $image->source;
}
if ($return = image_toolkit_invoke('save', $image, array($destination))) {
// Clear the cached file size and refresh the image information.
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;
}
}
return FALSE;
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}
/**
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* @} End of "defgroup image".