diff modules/system/theme.api.php @ 0:ff03f76ab3fe

initial version

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/modules/system/theme.api.php	Wed Aug 21 18:51:11 2013 +0100
@@ -0,0 +1,240 @@
+<?php
+
+/**
+ * @defgroup themeable Default theme implementations
+ * @{
+ * Functions and templates for the user interface to be implemented by themes.
+ *
+ * Drupal's presentation layer is a pluggable system known as the theme
+ * layer. Each theme can take control over most of Drupal's output, and
+ * has complete control over the CSS.
+ *
+ * Inside Drupal, the theme layer is utilized by the use of the theme()
+ * function, which is passed the name of a component (the theme hook)
+ * and an array of variables. For example,
+ * theme('table', array('header' => $header, 'rows' => $rows));
+ * Additionally, the theme() function can take an array of theme
+ * hooks, which can be used to provide 'fallback' implementations to
+ * allow for more specific control of output. For example, the function:
+ * theme(array('table__foo', 'table'), $variables) would look to see if
+ * 'table__foo' is registered anywhere; if it is not, it would 'fall back'
+ * to the generic 'table' implementation. This can be used to attach specific
+ * theme functions to named objects, allowing the themer more control over
+ * specific types of output.
+ *
+ * As of Drupal 6, every theme hook is required to be registered by the
+ * module that owns it, so that Drupal can tell what to do with it and
+ * to make it simple for themes to identify and override the behavior
+ * for these calls.
+ *
+ * The theme hooks are registered via hook_theme(), which returns an
+ * array of arrays with information about the hook. It describes the
+ * arguments the function or template will need, and provides
+ * defaults for the template in case they are not filled in. If the default
+ * implementation is a function, by convention it is named theme_HOOK().
+ *
+ * Each module should provide a default implementation for theme_hooks that
+ * it registers. This implementation may be either a function or a template;
+ * if it is a function it must be specified via hook_theme(). By convention,
+ * default implementations of theme hooks are named theme_HOOK. Default
+ * template implementations are stored in the module directory.
+ *
+ * Drupal's default template renderer is a simple PHP parsing engine that
+ * includes the template and stores the output. Drupal's theme engines
+ * can provide alternate template engines, such as XTemplate, Smarty and
+ * PHPTal. The most common template engine is PHPTemplate (included with
+ * Drupal and implemented in phptemplate.engine, which uses Drupal's default
+ * template renderer.
+ *
+ * In order to create theme-specific implementations of these hooks, themes can
+ * implement their own version of theme hooks, either as functions or templates.
+ * These implementations will be used instead of the default implementation. If
+ * using a pure .theme without an engine, the .theme is required to implement
+ * its own version of hook_theme() to tell Drupal what it is implementing;
+ * themes utilizing an engine will have their well-named theming functions
+ * automatically registered for them. While this can vary based upon the theme
+ * engine, the standard set by phptemplate is that theme functions should be
+ * named THEMENAME_HOOK. For example, for Drupal's default theme (Bartik) to
+ * implement the 'table' hook, the phptemplate.engine would find
+ * bartik_table().
+ *
+ * The theme system is described and defined in theme.inc.
+ *
+ * @see theme()
+ * @see hook_theme()
+ * @see hooks
+ * @see callbacks
+ *
+ * @} End of "defgroup themeable".
+ */
+
+/**
+ * Allow themes to alter the theme-specific settings form.
+ *
+ * With this hook, themes can alter the theme-specific settings form in any way
+ * allowable by Drupal's Form API, such as adding form elements, changing
+ * default values and removing form elements. See the Form API documentation on
+ * api.drupal.org for detailed information.
+ *
+ * Note that the base theme's form alterations will be run before any sub-theme
+ * alterations.
+ *
+ * @param $form
+ *   Nested array of form elements that comprise the form.
+ * @param $form_state
+ *   A keyed array containing the current state of the form.
+ */
+function hook_form_system_theme_settings_alter(&$form, &$form_state) {
+  // Add a checkbox to toggle the breadcrumb trail.
+  $form['toggle_breadcrumb'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Display the breadcrumb'),
+    '#default_value' => theme_get_setting('toggle_breadcrumb'),
+    '#description'   => t('Show a trail of links from the homepage to the current page.'),
+  );
+}
+
+/**
+ * Preprocess theme variables for templates.
+ *
+ * This hook allows modules to preprocess theme variables for theme templates.
+ * It is called for all theme hooks implemented as templates, but not for theme
+ * hooks implemented as functions. hook_preprocess_HOOK() can be used to
+ * preprocess variables for a specific theme hook, whether implemented as a
+ * template or function.
+ *
+ * For more detailed information, see theme().
+ *
+ * @param $variables
+ *   The variables array (modify in place).
+ * @param $hook
+ *   The name of the theme hook.
+ */
+function hook_preprocess(&$variables, $hook) {
+ static $hooks;
+
+  // Add contextual links to the variables, if the user has permission.
+
+  if (!user_access('access contextual links')) {
+    return;
+  }
+
+  if (!isset($hooks)) {
+    $hooks = theme_get_registry();
+  }
+
+  // Determine the primary theme function argument.
+  if (isset($hooks[$hook]['variables'])) {
+    $keys = array_keys($hooks[$hook]['variables']);
+    $key = $keys[0];
+  }
+  else {
+    $key = $hooks[$hook]['render element'];
+  }
+
+  if (isset($variables[$key])) {
+    $element = $variables[$key];
+  }
+
+  if (isset($element) && is_array($element) && !empty($element['#contextual_links'])) {
+    $variables['title_suffix']['contextual_links'] = contextual_links_view($element);
+    if (!empty($variables['title_suffix']['contextual_links'])) {
+      $variables['classes_array'][] = 'contextual-links-region';
+    }
+  }
+}
+
+/**
+ * Preprocess theme variables for a specific theme hook.
+ *
+ * This hook allows modules to preprocess theme variables for a specific theme
+ * hook. It should only be used if a module needs to override or add to the
+ * theme preprocessing for a theme hook it didn't define.
+ *
+ * For more detailed information, see theme().
+ *
+ * @param $variables
+ *   The variables array (modify in place).
+ */
+function hook_preprocess_HOOK(&$variables) {
+  // This example is from rdf_preprocess_image(). It adds an RDF attribute
+  // to the image hook's variables.
+  $variables['attributes']['typeof'] = array('foaf:Image');
+}
+
+/**
+ * Process theme variables for templates.
+ *
+ * This hook allows modules to process theme variables for theme templates. It
+ * is called for all theme hooks implemented as templates, but not for theme
+ * hooks implemented as functions. hook_process_HOOK() can be used to process
+ * variables for a specific theme hook, whether implemented as a template or
+ * function.
+ *
+ * For more detailed information, see theme().
+ *
+ * @param $variables
+ *   The variables array (modify in place).
+ * @param $hook
+ *   The name of the theme hook.
+ */
+function hook_process(&$variables, $hook) {
+  // Wraps variables in RDF wrappers.
+  if (!empty($variables['rdf_template_variable_attributes_array'])) {
+    foreach ($variables['rdf_template_variable_attributes_array'] as $variable_name => $attributes) {
+      $context = array(
+        'hook' => $hook,
+        'variable_name' => $variable_name,
+        'variables' => $variables,
+      );
+      $variables[$variable_name] = theme('rdf_template_variable_wrapper', array('content' => $variables[$variable_name], 'attributes' => $attributes, 'context' => $context));
+    }
+  }
+}
+
+/**
+ * Process theme variables for a specific theme hook.
+ *
+ * This hook allows modules to process theme variables for a specific theme
+ * hook. It should only be used if a module needs to override or add to the
+ * theme processing for a theme hook it didn't define.
+ *
+ * For more detailed information, see theme().
+ *
+ * @param $variables
+ *   The variables array (modify in place).
+ */
+function hook_process_HOOK(&$variables) {
+  // @todo There are no use-cases in Drupal core for this hook. Find one from a
+  //   contributed module, or come up with a good example. Coming up with a good
+  //   example might be tough, since the intent is for nearly everything to be
+  //   achievable via preprocess functions, and for process functions to only be
+  //   used when requiring the later execution time.
+}
+
+/**
+ * Respond to themes being enabled.
+ *
+ * @param array $theme_list
+ *   Array containing the names of the themes being enabled.
+ *
+ * @see theme_enable()
+ */
+function hook_themes_enabled($theme_list) {
+  foreach ($theme_list as $theme) {
+    block_theme_initialize($theme);
+  }
+}
+
+/**
+ * Respond to themes being disabled.
+ *
+ * @param array $theme_list
+ *   Array containing the names of the themes being disabled.
+ *
+ * @see theme_disable()
+ */
+function hook_themes_disabled($theme_list) {
+ // Clear all update module caches.
+  _update_cache_clear();
+}