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<?php
/**
* @file
* API for manipulating images.
*/
/**
* @defgroup image Image toolkits
* @{
* Functions for image file manipulations.
*
* 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 ImageMagick 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.
*
* Image toolkits are discovered based on the associated module's
* hook_image_toolkits. Additionally the image toolkit include file
* must be identified in the files array in the module.info file. The
* toolkit must then be enabled using the admin/config/media/image-toolkit
* form.
*
* 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.
*/
/**
* Return a list of available toolkits.
*
* @return
* An array with the toolkit names as keys and the descriptions as values.
*/
function image_get_available_toolkits() {
// hook_image_toolkits returns an array of toolkit names.
$toolkits = module_invoke_all('image_toolkits');
$output = array();
foreach ($toolkits as $name => $info) {
// Only allow modules that aren't marked as unavailable.
if ($info['available']) {
$output[$name] = $info['title'];
}
}
return $output;
}
/**
* Retrieve the name of the currently used toolkit.
*
* @return
* String containing the name of the selected toolkit, or FALSE on error.
*/
function image_get_toolkit() {
static $toolkit;
if (!isset($toolkit)) {
$toolkits = image_get_available_toolkits();
$toolkit = variable_get('image_toolkit', 'gd');
if (!isset($toolkits[$toolkit]) || !function_exists('image_' . $toolkit . '_load')) {
// The selected toolkit isn't available so return the first one found. If
// none are available this will return FALSE.
reset($toolkits);
$toolkit = key($toolkits);
}
}
return $toolkit;
}
/**
* Invokes the given method using the currently selected toolkit.
*
* @param $method
* A string containing the method to invoke.
* @param $image
* An image object returned by image_load().
* @param $params
* An optional array of parameters to pass to the toolkit method.
*
* @return
* Mixed values (typically Boolean indicating successful operation).
*/
function image_toolkit_invoke($method, stdClass $image, array $params = array()) {
$function = 'image_' . $image->toolkit . '_' . $method;
if (function_exists($function)) {
array_unshift($params, $image);
return call_user_func_array($function, $params);
}
watchdog('image', 'The selected image handling toolkit %toolkit can not correctly process %function.', array('%toolkit' => $image->toolkit, '%function' => $function), WATCHDOG_ERROR);
return FALSE;
}
/**
* Get details about an image.
*
* Drupal supports GIF, JPG and PNG file formats when used with the GD
* toolkit, and may support others, depending on which toolkits are
* installed.
*
* @param $filepath
* String specifying the path of the image file.
* @param $toolkit
* An optional image toolkit name to override the default.
*
* @return
* FALSE, if the file could not be found or is not an image. Otherwise, a
* keyed array containing information about the image:
* - "width": Width, in pixels.
* - "height": Height, in pixels.
* - "extension": Commonly used file extension for the image.
* - "mime_type": MIME type ('image/jpeg', 'image/gif', 'image/png').
* - "file_size": File size in bytes.
*/
function image_get_info($filepath, $toolkit = FALSE) {
$details = FALSE;
if (!is_file($filepath) && !is_uploaded_file($filepath)) {
return $details;
}
if (!$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);
}
}
return $details;
}
/**
* 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.
*
* @param $image
* An image object returned by image_load().
* @param $width
* The target width, in pixels.
* @param $height
* The target height, in pixels.
*
* @return
* TRUE on success, FALSE on failure.
*
* @see image_load()
* @see image_resize()
* @see image_crop()
*/
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 - $height) / 2;
if (image_resize($image, $image->info['width'] * $scale, $image->info['height'] * $scale)) {
return image_crop($image, $x, $y, $width, $height);
}
return FALSE;
}
/**
* Scales image dimensions while maintaining aspect ratio.
*
* The resulting dimensions can be smaller for one or both target dimensions.
*
* @param $dimensions
* Dimensions to be modified - an array with components width and height, in
* pixels.
* @param $width
* The target width, in pixels. If this value is NULL then the scaling will be
* based only on the height value.
* @param $height
* The target height, in pixels. If this value is NULL then the scaling will
* be based only on the width value.
* @param $upscale
* Boolean indicating that images smaller than the target dimensions will be
* scaled up. This generally results in a low quality image.
*
* @return
* TRUE if $dimensions was modified, FALSE otherwise.
*
* @see image_scale()
*/
function image_dimensions_scale(array &$dimensions, $width = NULL, $height = NULL, $upscale = FALSE) {
$aspect = $dimensions['height'] / $dimensions['width'];
// Calculate one of the dimensions from the other target dimension,
// ensuring the same aspect ratio as the source dimensions. If one of the
// target dimensions is missing, that is the one that is calculated. If both
// are specified then the dimension calculated is the one that would not be
// calculated to be bigger than its target.
if (($width && !$height) || ($width && $height && $aspect < $height / $width)) {
$height = (int) round($width * $aspect);
}
else {
$width = (int) round($height / $aspect);
}
// Don't upscale if the option isn't enabled.
if (!$upscale && ($width >= $dimensions['width'] || $height >= $dimensions['height'])) {
return FALSE;
}
$dimensions['width'] = $width;
$dimensions['height'] = $height;
return TRUE;
}
/**
* Scales an image while maintaining aspect ratio.
*
* The resulting image can be smaller for one or both target dimensions.
*
* @param $image
* An image object returned by image_load().
* @param $width
* The target width, in pixels. This value is omitted then the scaling will
* based only on the height value.
* @param $height
* 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 scaled
* up. This generally results in a low quality image.
*
* @return
* TRUE on success, FALSE on failure.
*
* @see image_dimensions_scale()
* @see image_load()
* @see image_scale_and_crop()
*/
function image_scale(stdClass $image, $width = NULL, $height = NULL, $upscale = FALSE) {
$dimensions = $image->info;
// Scale the dimensions - if they don't change then just return success.
if (!image_dimensions_scale($dimensions, $width, $height, $upscale)) {
return TRUE;
}
return image_resize($image, $dimensions['width'], $dimensions['height']);
}
/**
* Resize an image to the given dimensions (ignoring aspect ratio).
*
* @param $image
* An image object returned by image_load().
* @param $width
* The target width, in pixels.
* @param $height
* The target height, in pixels.
*
* @return
* TRUE on success, FALSE on failure.
*
* @see image_load()
* @see image_gd_resize()
*/
function image_resize(stdClass $image, $width, $height) {
$width = (int) round($width);
$height = (int) round($height);
return image_toolkit_invoke('resize', $image, array($width, $height));
}
/**
* 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 on success, FALSE on failure.
*
* @see image_load()
* @see image_gd_rotate()
*/
function image_rotate(stdClass $image, $degrees, $background = NULL) {
return image_toolkit_invoke('rotate', $image, array($degrees, $background));
}
/**
* Crop an image to the rectangle specified by the given rectangle.
*
* @param $image
* An image object returned by image_load().
* @param $x
* The top left coordinate, in pixels, of the crop area (x axis value).
* @param $y
* The top left coordinate, in pixels, of the crop area (y axis value).
* @param $width
* The target width, in pixels.
* @param $height
* The target height, in pixels.
*
* @return
* TRUE on success, FALSE on failure.
*
* @see image_load()
* @see image_scale_and_crop()
* @see image_gd_crop()
*/
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 on success, FALSE on failure.
*
* @see image_load()
* @see image_gd_desaturate()
*/
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 $toolkit
* An optional, image toolkit name to override the default.
*
* @return
* An image object or FALSE if there was a problem loading the file. The
* image object has the following properties:
* - 'source' - The original file path.
* - 'info' - The array of information returned by image_get_info()
* - 'toolkit' - The name of the image toolkit requested when the image was
* loaded.
* Image toolkits may add additional properties. The caller is advised not to
* monkey about with them.
*
* @see image_save()
* @see image_get_info()
* @see image_get_available_toolkits()
* @see image_gd_load()
*/
function image_load($file, $toolkit = FALSE) {
if (!$toolkit) {
$toolkit = image_get_toolkit();
}
if ($toolkit) {
$image = new stdClass();
$image->source = $file;
$image->info = image_get_info($file, $toolkit);
if (isset($image->info) && is_array($image->info)) {
$image->toolkit = $toolkit;
if (image_toolkit_invoke('load', $image)) {
return $image;
}
}
}
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 on success, FALSE on failure.
*
* @see image_load()
* @see image_gd_save()
*/
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();
$image->info = image_get_info($destination, $image->toolkit);
if (drupal_chmod($destination)) {
return $return;
}
}
return FALSE;
}
/**
* @} End of "defgroup image".
*/
