I was also answering to your question stellablue and I also advise your to use Smarty prefilters. Here is my version of the plugin code:

add_event_handler('loc_end_picture', 'pAnchor_add_anchor');
function pAnchor_add_anchor()
{
  global $template;
  $template->set_prefilter('picture', 'pAnchor_add_anchor_prefilter');
}

function pAnchor_add_anchor_prefilter($content, &$smarty)
{
  $search = '#<div id="imageHeaderBar"#';
  $replacement = '<a name="pAnchor"></a><div id="imageHeaderBar"';
  return preg_replace($search, $replacement, $content);
}

In this very specific case, you can also write

add_event_handler('loc_end_picture', 'pAnchor_add_anchor');
function pAnchor_add_anchor()
{
  global $template;
  $template->assign(
    'PLUGIN_PICTURE_BEFORE',
    '<a name="pAnchor"></a>'
    );
}

but this is very very specific, you'd better learn to use Smarty prefilters, they let you do nearly anything you need to transform *.tpl files.

Thanks ddtddt & plg!!  prefilter will do the trick.  Can I be assured that  <div id="imageToolBar"> exists in .tpl?  Do all themes have this element to reference?  I suppose it could fail gracefully if div not found or push error and inform user to disable plug-in or manual place <a name="{$PANCHOR_NAME}></a> in picture.tpl.

well, let me implement the prefilter.  Is best way to add a single css style definition (for this plugin) by using the $template->append('header_elements', $css_code)?  - stellablue

(edit:  grep totally awesome, use it plenty to search within piwigo for vars, trigger_events and such!)

Last edited by stellablue (2010-11-09 22:19:21)

great thanks!  Ok, got the prefilter in and plug-in works!  question I have is I had followed a post on plug-in development that made my plug-in a class and the add_event_handler call was different that what you recommended (ref [Forum, topic 14880] Create a Piwigo extension for dumies).

I just left those functions you recommended  out of the class definition.  But how should plug-ins be made as public functions or classes?

here are the 2 statements (first is part of  pAnchor class in $obj):

add_event_handler('render_element_content', array(&$obj, 'pAnchor_links'),50,2);

(this is what you recommended)
add_event_handler('loc_end_picture', 'pAnchor_add_anchor');


Could I have put your functions in pAnchor class and setup proper pre-filter?

thanks again - stellablue

PS: when plug-in totally polished, what is recommend testing & submittal to pwigo?

Hi plg,

thanks for your help.  Yes, I ran into same road-block with prefilter inside class definition.  No matter how you specify the prefilter function, php kicks back an error.  Must be something inherit in smarty about resolving the prefilter function address inside an class object, no?

I will create my extensions at the link you provided. 
  1.  The pAnchor one (adds # page anchor to urls for improved browsing) works well.  It searches for the <div id="imageHeaderBar"> by default and adds the anchor.  The search string is defined in main.inc.php for the plugin and can be adjusted for different templates.

2. the pGravator plugin sets a template array variable {$gravatars} with the gravatar image urls.  Now, I adjusted comments-list.tpl for my theme to utilize this variable and style correctly.  How would others implement this?  Is it ok to expect piwigo users to adjust .tpl / css for a plug-in?  I could provide snippets so users can incorporate into their theme. 

3. the fsSlideShow plugin is the fullscreen flash slideshow works good, but I have discovered some licensing issues.  I am exploring an open-source solution so a fullscreen plugin is available.  if you wish to discuss please send pm or to my account e-mail.

thanks again for your help and patience with a piwigo rookie ;-)