Output renderers

Revision as of 19:42, 7 January 2010 by Petr Škoda (škoďák) (talk | contribs) (core_renderer)

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Output renderers
Project state Specification
Tracker issue MDL-21235
Discussion n/a
Assignee Petr Škoda (škoďák) + David Mudrak + feedback and ideas from other developers

Moodle 2.0


  • stable API
  • easy to use
  • easy to customise via themes


Output renderer is a class with collection of methods that handle rendering of visual aspects of Moodle pages, emails, html export, etc. In 1.9 general output related functions were located in weblib.php and modules stored rendering code in lib.php, locallib.php, view.php, etc.

Output renderer instances are obtained through moodle_page::get_renderer($component, $subtype = null, $target = null) method. Current core_renderer is available through the global $OUTPUT variable, please note this global should not be used in low level APIs.

Renderer targets


Abstract class every other renderer must extend. Renderer base implements basic methods and support for renderer dispatching. The most important method is render(), it is using class name of the widget passed in first parameter to find fine correct protected rendering method (widget rendering methods have render_ prefix.


Core renderer implements:

  1. page header and footer related rendering
  2. boxes and containers
  3. general widget methods - heading, single button, select form, heading, arrows, language selection, user login info

For example user avatar rendering involves following methods and classes:

class core_renderer extends renderer_base {
  // ...
  public function render(widget $widget) {
     // calls $this->render_user_image($widget) when parameter with class user_image submitted 
  protected function render_user_image(user_image $user_image) {
    // returns html markup for user avatar
  public function user_image($userrecord, array $options=null) {
    // helper method that constructs $user_image widget and calls $this->render
  // ...
class user_image extends widget {
  public $userrecord;
  public $options;
  public function __construct($userrecord, array $options=null) {
      // ...


Core subsystem renderers

Plugin renderers

Bootstrap renderer

Theme customisations

Theme renderers

HTML output

See also