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Introduction - renderers

Introduction - renderers -- How to output the form

What are renderers?

Before release 3.0, form outputting logic was implemented as methods of HTML_QuickForm class. This led to two problems:

  1. Bloat of the said class (80+ methods!)

  2. 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:

  1. Code for some particular output method is loaded only when the method is used.

  2. 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:
// 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
// output the results
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.

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