Thank you for your update with the good news regarding the 20150206 MLA Development Version.
Regarding “this article mentions ImageMagik“, I have looked at that in the past but it requires both ImageMagik and GhostScript to be installed on the server, and I don’t know how universal that configuration is. If you are interested in a solution along those lines I can work with you to try it out. It would be a useful extension to my “custom plugin” answer to your next question.
Regarding “Is there a way to include a caption only for the PDF icons?“, I have developed a small custom plugin that provides this feature. The complete example plugin has been uploaded to the MLA Development Version (20150210). You can find it in the /examples/mla-viewer-replacement-example.php.txt file. Here are the essential elements.
The initialize function hooks three of the provided filters when called from the “front end” site:
public static function initialize() {
/*
* The filters are only useful for front-end posts/pages; exit if in the admin section
*/
if ( is_admin() )
return;
/*
* add_filter parameters:
*/
add_filter( 'mla_gallery_raw_attributes', 'MLAViewerReplacement::mla_gallery_raw_attributes', 10, 1 );
add_filter( 'mla_gallery_arguments', 'MLAViewerReplacement::mla_gallery_arguments_filter', 10, 1 );
add_filter( 'mla_gallery_item_values', 'MLAViewerReplacement::mla_gallery_item_values_filter', 10, 1 );
}
The raw attributes filter captures the shortcode parameters and saves them for use in the items filter. The gallery arguments filter captures all of the possible parameters, including default values for the list of file extensions used by the “viewer” logic.
The interesting code is in the item values filter. This filter is called once for each item in the gallery, and is supplied with all of the substitution parameter values ($item_values) for the item, e.g., the file name for the item.
public static function mla_gallery_item_values_filter( $item_values ) {
/*
* We use a shortcode parameter of our own to apply our filters on a
* gallery-by-gallery basis, leaving other [mla_gallery] instances untouched.
* If "mla_viewer_caption" is not present, we have nothing to do. Here is
* an example of how the custom parameter can be used:
*
* [mla_gallery ids="2621,2622,2623" mla_viewer=true mla_viewer_caption="{+title+}"]
*/
if ( ! isset( self::$shortcode_attributes['mla_viewer_caption'] ) ) {
return $item_values;
}
$extension = pathinfo( $item_values['file'], PATHINFO_EXTENSION );
if ( false === strpos( self::$all_display_parameters['mla_viewer_extensions'], $extension ) ) {
return $item_values;
}
// You can use MLAOptions::mla_get_data_source() to get anything available.
$mla_viewer_caption = str_replace( '{+', '[+', str_replace( '+}', '+]', self::$shortcode_attributes['mla_viewer_caption'] ) );
$data_source = array(
'data_source' => 'template',
'meta_name' => $mla_viewer_caption,
'option' => 'text'
);
$mla_viewer_caption = MLAOptions::mla_get_data_source( $item_values['attachment_ID'], 'single_attachment_mapping', $data_source, NULL );
$item_values['caption'] = $mla_viewer_caption;
return $item_values;
} // mla_gallery_item_values_filter
As you can see, this function looks for a mla_viewer_caption parameter. If the parameter is present and, if the item has a file extension that matches an entry in the mla_viewer_extensions list, a new caption is composed for the item. The parameter value is a Content Template, so you can compose a new caption from multiple sources. For example, if you code:
[mla_gallery ids="2621" mla_viewer=true mla_viewer_caption="({+post_excerpt+}|{+post_title+}"]
The caption for “viewer” items such as PDF documents will be the post_excerpt (the default caption) if the item has one or the post_title (the item’s Title) if the post_excerpt is empty.
You can combine this custom parameter with the existing mla_caption parameter for other gallery items like images. Each file type will get the appropriate value.
I encourage you to download the latest version and let me know how it works for you. Thanks for continuing an interesting topic.
