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- <?php
- /**
- * @file
- * Hooks related to image styles and effects.
- */
- /**
- * @addtogroup hooks
- * @{
- */
- /**
- * Define information about image effects provided by a module.
- *
- * This hook enables modules to define image manipulation effects for use with
- * an image style.
- *
- * @return
- * An array of image effects. This array is keyed on the machine-readable
- * effect name. Each effect is defined as an associative array containing the
- * following items:
- * - "label": The human-readable name of the effect.
- * - "effect callback": The function to call to perform this image effect.
- * - "dimensions passthrough": (optional) Set this item if the effect doesn't
- * change the dimensions of the image.
- * - "dimensions callback": (optional) The function to call to transform
- * dimensions for this effect.
- * - "help": (optional) A brief description of the effect that will be shown
- * when adding or configuring this image effect.
- * - "form callback": (optional) The name of a function that will return a
- * $form array providing a configuration form for this image effect.
- * - "summary theme": (optional) The name of a theme function that will output
- * a summary of this image effect's configuration.
- *
- * @see hook_image_effect_info_alter()
- */
- function hook_image_effect_info() {
- $effects = array();
- $effects['mymodule_resize'] = array(
- 'label' => t('Resize'),
- 'help' => t('Resize an image to an exact set of dimensions, ignoring aspect ratio.'),
- 'effect callback' => 'mymodule_resize_effect',
- 'dimensions callback' => 'mymodule_resize_dimensions',
- 'form callback' => 'mymodule_resize_form',
- 'summary theme' => 'mymodule_resize_summary',
- );
- return $effects;
- }
- /**
- * Alter the information provided in hook_image_effect_info().
- *
- * @param $effects
- * The array of image effects, keyed on the machine-readable effect name.
- *
- * @see hook_image_effect_info()
- */
- function hook_image_effect_info_alter(&$effects) {
- // Override the Image module's crop effect with more options.
- $effects['image_crop']['effect callback'] = 'mymodule_crop_effect';
- $effects['image_crop']['dimensions callback'] = 'mymodule_crop_dimensions';
- $effects['image_crop']['form callback'] = 'mymodule_crop_form';
- }
- /**
- * Respond to image style updating.
- *
- * This hook enables modules to update settings that might be affected by
- * changes to an image. For example, updating a module specific variable to
- * reflect a change in the image style's name.
- *
- * @param $style
- * The image style array that is being updated.
- */
- function hook_image_style_save($style) {
- // If a module defines an image style and that style is renamed by the user
- // the module should update any references to that style.
- if (isset($style['old_name']) && $style['old_name'] == variable_get('mymodule_image_style', '')) {
- variable_set('mymodule_image_style', $style['name']);
- }
- }
- /**
- * Respond to image style deletion.
- *
- * This hook enables modules to update settings when a image style is being
- * deleted. If a style is deleted, a replacement name may be specified in
- * $style['name'] and the style being deleted will be specified in
- * $style['old_name'].
- *
- * @param $style
- * The image style array that being deleted.
- */
- function hook_image_style_delete($style) {
- // Administrators can choose an optional replacement style when deleting.
- // Update the modules style variable accordingly.
- if (isset($style['old_name']) && $style['old_name'] == variable_get('mymodule_image_style', '')) {
- variable_set('mymodule_image_style', $style['name']);
- }
- }
- /**
- * Respond to image style flushing.
- *
- * This hook enables modules to take effect when a style is being flushed (all
- * images are being deleted from the server and regenerated). Any
- * module-specific caches that contain information related to the style should
- * be cleared using this hook. This hook is called whenever a style is updated,
- * deleted, or any effect associated with the style is update or deleted.
- *
- * @param $style
- * The image style array that is being flushed.
- */
- function hook_image_style_flush($style) {
- // Empty cached data that contains information about the style.
- cache_clear_all('*', 'cache_mymodule', TRUE);
- }
- /**
- * Modify any image styles provided by other modules or the user.
- *
- * This hook allows modules to modify, add, or remove image styles. This may
- * be useful to modify default styles provided by other modules or enforce
- * that a specific effect is always enabled on a style. Note that modifications
- * to these styles may negatively affect the user experience, such as if an
- * effect is added to a style through this hook, the user may attempt to remove
- * the effect but it will be immediately be re-added.
- *
- * The best use of this hook is usually to modify default styles, which are not
- * editable by the user until they are overridden, so such interface
- * contradictions will not occur. This hook can target default (or user) styles
- * by checking the $style['storage'] property.
- *
- * If your module needs to provide a new style (rather than modify an existing
- * one) use hook_image_default_styles() instead.
- *
- * @see hook_image_default_styles()
- */
- function hook_image_styles_alter(&$styles) {
- // Check that we only affect a default style.
- if ($styles['thumbnail']['storage'] == IMAGE_STORAGE_DEFAULT) {
- // Add an additional effect to the thumbnail style.
- $styles['thumbnail']['effects'][] = array(
- 'name' => 'image_desaturate',
- 'data' => array(),
- 'weight' => 1,
- 'effect callback' => 'image_desaturate_effect',
- );
- }
- }
- /**
- * Provide module-based image styles for reuse throughout Drupal.
- *
- * This hook allows your module to provide image styles. This may be useful if
- * you require images to fit within exact dimensions. Note that you should
- * attempt to re-use the default styles provided by Image module whenever
- * possible, rather than creating image styles that are specific to your module.
- * Image provides the styles "thumbnail", "medium", and "large".
- *
- * You may use this hook to more easily manage your site's changes by moving
- * existing image styles from the database to a custom module. Note however that
- * moving image styles to code instead storing them in the database has a
- * negligible effect on performance, since custom image styles are loaded
- * from the database all at once. Even if all styles are pulled from modules,
- * Image module will still perform the same queries to check the database for
- * any custom styles.
- *
- * @return
- * An array of image styles, keyed by the style name.
- * @see image_image_default_styles()
- */
- function hook_image_default_styles() {
- $styles = array();
- $styles['mymodule_preview'] = array(
- 'label' => 'My module preview',
- 'effects' => array(
- array(
- 'name' => 'image_scale',
- 'data' => array('width' => 400, 'height' => 400, 'upscale' => 1),
- 'weight' => 0,
- ),
- array(
- 'name' => 'image_desaturate',
- 'data' => array(),
- 'weight' => 1,
- ),
- ),
- );
- return $styles;
- }
- /**
- * @} End of "addtogroup hooks".
- */
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