how to skip images with certain class in wordpress function - php

Question

I have the following function in my theme's function page. basically what it does is look for any image in the post page and add some spans with css to dynamically create a pinterest button.
function insert_pinterest($content) {
global $post;
$posturl = urlencode(get_permalink()); //Get the post URL
$pinspan = '<span class="pinterest-button">';
$pinurlNew = '<a href="#" onclick="window.open("http://pinterest.com/pin/create/button/?url='.$posturl.'&media=';
$pindescription = '&description='.urlencode(get_the_title());
$options = '","Pinterest","scrollbars=no,menubar=no,width=600,height=380,resizable=yes,toolbar=no,location=no,status=no';
$pinfinish = '");return false;" class="pin-it"></a>';
$pinend = '</span>';
$pattern = '/<img(.*?)src="(.*?).(bmp|gif|jpeg|jpg|png)"(.*?) \/>/i';
$replacement = $pinspan.$pinurlNew.'$2.$3'.$pindescription.$options.$pinfinish.'<img$1src="$2.$3" $4 />'.$pinend;
$content = preg_replace( $pattern, $replacement, $content );
//Fix the link problem
$newpattern = '/<a(.*?)><span class="pinterest-button"><a(.*?)><\/a><img(.*?)\/><\/span><\/a>/i';
$replacement = '<span class="pinterest-button"><a$2></a><a$1><img$3\/></a></span>';
$content = preg_replace( $newpattern, $replacement, $content );
return $content;
}
add_filter( 'the_content', 'insert_pinterest' );
it does everything just fine. but is there a way to have it skip over an image with a certain class name in it like "noPin" ?

Answer 1

I would use preg_replace_callback to check if a matched image contains noPin.
function skipNoPin($matches){
if ( strpos($matches[0], "noPin") === false){
return $pinspan.$pinurlNew.'$matches[2].$matches[3]'.$pindescription.$options.$pinfinish.'<img$1src="$2.$3" $4 />'.$pinend;
} else {
return $matches[0]
$content = preg_replace_callback(
$pattern,
skipNoPin,
$content );
Another image attribute could conceivably contain noPin, if you are concerned about that edge case, just make the test in the if statement more specific.

Answer 2

You have to exclude the class noPin from the $pattern regexp :
$pattern = '/<img(.*?)src="(.*?).(bmp|gif|jpeg|jpg|png)"(.*?) \/>/i';
Has to become something like
$pattern = '/<img(.*?)src="(.*?).(bmp|gif|jpeg|jpg|png)"(.*?) (?!class="noPin") \/>/i';
Please check the regexp syntax, but the idea is to exclude class="noPin" from the searched pattern. Then your replacement will not be added to these images.