What are renderers?
Before release 3.0, form outputting logic was implemented as methods of HTML_QuickForm 
class. This led to two problems:
- Bloat of the said class (80+ methods!) 
- Difficulties in adding new output logic (i.e. using template engines) 
In release 3.0, new system was implemented. The form output logic is now contained 
in classes that extend HTML_QuickForm_Renderer, their behaviour is based on Visitor 
design pattern from the classic "Design Patterns" book. This gives the 
following advantages:
- 
    Code for some particular output method is loaded only 
    when the method is used.
   
- 
    It is much easier to add new output method.
   
There are 8 renderers available since release 3.1.1, of which 2 are based on pre-3.0 code and 6 are new. The following template engines are directly suported: Smarty, HTML_Template_Sigma, HTML_Template_IT, HTML_Template_Flexy.
    
The main steps of using any available renderer are quite similar:
| <?php
// include the renderer class
require_once 'HTML/QuickForm/Renderer/FooBar.php';
// instantiate the renderer
$renderer =& new HTML_QuickForm_Renderer_FooBar($options);
// do some customization
$renderer->adjustSomething('element1', '...');
// ...
$renderer->adjustSomething('elementN', '...');
// process the form
$form->accept($renderer);
// output the results
$renderer->toFooBar();
?> | 
Actual methods for customization and doing the output will of course depend on renderer type.
    
Concerning usage examples: 
      Usage examples provided in the manual are pretty basic. More complex examples for Default
      renderer can be found in docs/ directory, for all other
      renderers - in docs/renderers/ directory of HTML_QuickForm.