mirgcire

stianlik

<p>This plugin hooks into the media manager and generates a thumbnail everytime a<br />
PDF is uploaded. Generated thumbnail is an image of the first page in the<br />
uploaded document and is named <code>PDFNAME-thumbnail</code>, where <code>PDFNAME</code> is replaced<br />
by uploaded document filename.</p>
<p>Generated thumbnails are equivalent to <a href="https://codex.wordpress.org/Post_Thumbnails" rel="nofollow ugc">featured<br />
images</a> so that common thumbnail<br />
functions like <code>get_post_thumbnail_id()</code> can be used for PDF attachments. See<br />
<a href="https://codex.wordpress.org/Post_Thumbnails" rel="nofollow ugc">Post Thumbnails</a> for information<br />
on how you can use thumbnails efficiently.</p>
<p>Integration with the javascript media API is not yet implemented, therefore, you<br />
may need to reload the page before you can see generated thumbnail after an<br />
upload.</p>
<h4>Shortcodes</h4>
<p>It is possible to display a thumbnail linking to an uploaded PDF using the <code>[pdf_thumbnails_link]</code><br />
shortcode. The following attributes are supported:</p>
<ul>
<li><code>id</code> – Attachment ID (required)</li>
<li><code>size</code> – <a href="https://codex.wordpress.org/Post_Thumbnails#Thumbnail_Sizes" rel="nofollow ugc">Thumbnail size</a> (optional)</li>
<li><code>title</code> – <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes#attr-title" rel="nofollow ugc">Anchor title attribute</a> (optional)</li>
<li><code>target</code> – <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#attr-target" rel="nofollow ugc">Anchor target attribute</a> (optional)</li>
<li><code>download</code> – <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#attr-download" rel="nofollow ugc">Anchor download attribute</a> (optional)</li>
</ul>
<p>Example 1: Display link to PDF with ID = 172 using <a href="https://codex.wordpress.org/Post_Thumbnails#Thumbnail_Sizes" rel="nofollow ugc">default thumbnail size</a></p>
<pre><code>[pdf_thumbnails_link id="172"]
</code></pre>
<p>Example 2: Display link to PDF with ID = 172 using thumbnail size (default 150×150)</p>
<pre><code>[pdf_thumbnails_link id="172" size="thumbnail"]
</code></pre>
<p>Thanks to <a href="https://wordpress.org/support/profile/mirgcire" rel="ugc">mirgcire</a> for providing the first<br />
version of the <code>[pdf_thumbnails_link]</code> shortcode.</p>
<h4>Developer API</h4>
<p>In most cases it should be sufficient to use built-in thumbnail functions from<br />
the WordPress API (<code>get_post_thumbnail</code> and similar). If you need to modify the<br />
way thumbnails are generated, you can override image generation with<br />
the <code>pdf_thumbnails_generate_image_blob</code> filter.</p>
<p>Example 1: Increase resolution for all generated PDF thumbnails</p>
<pre><code>// $blob is the current image blob (defaults to null, can be used for chaining)
// $filename is the PDF filename
add_action('pdf_thumbnails_generate_image_blob', function ($blob, $filename) {
    $imagick = new Imagick();
    $imagick->setResolution(200,200);
    $imagick->readImage($filename);
    $imagick->setIteratorIndex(0);
    $imagick->setImageFormat('jpg');
    return $imagick->getImageBlob();
}, 10, 2);
</code></pre>
<p>It is possible to modify generated thumbnail links using the <code>pdf_thumbnails_link_shortcode</code><br />
filter. The following attributes are available:</p>
<ul>
<li><code>$html</code> – Generated HTML code to be displayed</li>
<li><code>$attachmentId</code> – Sanitized ID of the PDF attachment</li>
<li><code>$size</code> – Sanitized thumbnail size</li>
<li><code>$atts</code> – <a href="https://codex.wordpress.org/Shortcode_API#Handling_Attributes" rel="nofollow ugc">Shortcode attributes (not sanitized)</a></li>
<li><code>$content</code> – Shortcode content (not sanitized)</li>
</ul>
<p>Example 2: Wrap thumbnail link in figure and append caption</p>
<pre><code>add_filter('pdf_thumbnails_link_shortcode', function ($html, $attachmentId, $size, $atts, $content) {
    return "<figure>$html <caption>Click to open image $attachmentId</caption></figure>";
}, 10, 5);
</code></pre>
<h3>TODO</h3>
<p>Add generated image to media browser after upload.</p>
<p>Outline of an implementation based on the javascript media API:</p>
<pre><code>// New uploads
wp.Uploader.queue.on('add', function (attachment) {

    if (attachment.subtype !== 'pdf') {
        return;
    }

    findThumbnailFor(attachment.ID).then(function (data) {

        // Add attachment thumbnail to browser
        var attachment = wp.media.model.Attachment.get(id)
        attachment.fetch().done(function () {
            wp.media.editor.open().state().get('library').add(generated attachment)
        });

    });
});
</code></pre>
<p>Filter: ajax_query_attachments_args</p>


PDF Thumbnails

The plugin does just what it says and the author is very helpful.  My only suggestion would be to add a short code that would insert a clickable thumbnail into a webpage.  Clicking on that would open the PDF in a viewer.
For example: [pdf-thumbnail id="1234" size="medium"]
... naturally this functionality would require host support for imagick.



Nice Job

Works just like it should. Can't believe this functionality isn't in the WP core. Thanks!

Excellent

This plugin generates a thumbnail everytime you upload a PDF attachment. Generated thumbnail is an image of the first page in uploaded document.

kubiq

<p>Generates thumbnail for PDF file automatically after file is uploaded to the Media library.</p>
<p>You can also generate thumbnails for old PDF files that are already in the Media library – you can generate missing thumbnails or regenerate all thumbnails.</p>
<p><strong>Imagick library must be installed on your server, otherwise this plugin will not work</strong></p>
<ul>
<li>automated test after plugin activation to make sure it will work on your server</li>
<li>works with all types of WordPress installations: domain, subdomain, subdirectory, multisite/network</li>
<li>works on Apache and NGiNX</li>
<li>automatically generate thumbnail for new uploaded PDFs</li>
<li>(re)generate thumbnails for existing PDFs in Media library</li>
<li>set maximum width of PDF thumbnail</li>
<li>set maximum height of PDF thumbnail</li>
<li>set image quality of PDF thumbnail</li>
<li>set image file type of PDF thumbnail</li>
</ul>
<h3>Shortcodes</h3>
<h3>pdf_thumbnail</h3>
<p>Maybe you want to display PDF thumbnail by using a shortcode</p>
<pre><code>[pdf_thumbnail id="123"]
</code></pre>
<h3>pdf_thumbnail_url</h3>
<p>Maybe you want to display PDF thumbnail url by using a shortcode</p>
<pre><code>[pdf_thumbnail_url id="123"]
</code></pre>
<h3>pdf_clickable_thumbnail</h3>
<p>Maybe you want to display clickable PDF thumbnail that will open PDF in new tab</p>
<pre><code>[pdf_clickable_thumbnail id="123"]
</code></pre>
<p> </p>
<h3>Functions</h3>
<h3>get_pdf_thumbnail_url</h3>
<p>If you want to return PDF thumbnail URL you can use</p>
<pre><code>get_pdf_thumbnail_url( $pdf_id )
</code></pre>
<p>it works similar to <code>wp_get_attachment_url</code> and it will return something like</p>
<pre><code>https://site.com/wp-content/uploads/2022/01/example.pdf.png
</code></pre>
<h3>get_pdf_thumbnail_path</h3>
<p>If you want to return PDF thumbnail URL you can use</p>
<pre><code>get_pdf_thumbnail_path( $pdf_id )
</code></pre>
<p>it works similar to <code>get_attached_file</code> and it will return something like</p>
<pre><code>/www/site.com/wp-content/uploads/2022/01/example.pdf.png
</code></pre>
<h3>get_pdf_thumbnail_image_src</h3>
<p>If you want to return PDF thumbnail url, width and height you can use</p>
<pre><code>get_pdf_thumbnail_image_src( $pdf_id )
</code></pre>
<p>it works similar to <code>wp_get_attachment_image_src</code> and it will return something like</p>
<pre><code>[
    0 => 'https://site.com/wp-content/uploads/2022/01/example.pdf.png',
    1 => 600,
    2 => 800
]
</code></pre>
<h3>get_pdf_thumbnail_image</h3>
<p>If you want to return PDF thumbnail image tag you can use</p>
<pre><code>get_pdf_thumbnail_image( $pdf_id )
</code></pre>
<p>it works similar to <code>wp_get_attachment_image</code> and it will return something like</p>
<pre><code><img src="https://site.com/wp-content/uploads/2022/01/example.pdf.png" width="600" height="800" alt="example" loading="lazy">
</code></pre>
<p> </p>
<h3>Hooks</h3>
<h3>pdf_thumbnail_max_width</h3>
<p>Maybe you want to change global PDF thumbnail max_width for a specific PDF file</p>
<pre><code>add_filter( 'pdf_thumbnail_max_width', function( $max_width, $pdf_id ){
    if( $pdf_id == 123 ){
        return 1024;
    }
    return $max_width;
}, 10, 2 );
</code></pre>
<h3>pdf_thumbnail_max_height</h3>
<p>Maybe you want to change global PDF thumbnail max_width for a specific PDF file</p>
<pre><code>add_filter( 'pdf_thumbnail_max_height', function( $max_height, $pdf_id ){
    if( $pdf_id == 123 ){
        return 768;
    }
    return $max_height;
}, 10, 2 );
</code></pre>
<h3>pdf_thumbnail_quality</h3>
<p>Maybe you want to change global PDF thumbnail quality for a specific PDF file</p>
<pre><code>add_filter( 'pdf_thumbnail_quality', function( $quality, $pdf_id ){
    if( $pdf_id == 123 ){
        return 100;
    }
    return $quality;
}, 10, 2 );
</code></pre>
<h3>pdf_thumbnail_type</h3>
<p>Maybe you want to change global PDF thumbnail file type for a specific PDF file</p>
<pre><code>add_filter( 'pdf_thumbnail_type', function( $type, $pdf_id ){
    if( $pdf_id == 123 ){
        return 'png'; // or 'jpg'
    }
    return $type;
}, 10, 2 );
</code></pre>
<h3>pdf_thumbnail_bgcolor</h3>
<p>Maybe you want to change default PDF thumbnail background for a specific PDF file</p>
<pre><code>add_filter( 'pdf_thumbnail_bgcolor', function( $bgcolor, $pdf_id ){
    if( $pdf_id == 123 ){
        return 'black'; // default is 'white'
    }
    return $bgcolor;
}, 10, 2 );
</code></pre>
<h3>pdf_thumbnail_page_number</h3>
<p>Maybe you want to PDF thumbnail page number for a specific PDF file</p>
<pre><code>add_filter( 'pdf_thumbnail_page_number', function( $page, $pdf_id ){
    if( $pdf_id == 123 ){
        return 1; // default is 0
    }
    return $page;
}, 10, 2 );
</code></pre>
<h3>pdf_thumbnail_filename</h3>
<p>Maybe you want to PDF thumbnail filename for a specific PDF file</p>
<pre><code>add_filter( 'pdf_thumbnail_filename', function( $filename, $pdf_id ){
    if( $pdf_id == 123 ){
        return str_replace( '.pdf.png', '.png', $filename );
    }
    return $filename;
}, 10, 2 );
</code></pre>
<h3>pdf_thumbnail_imagick</h3>
<p>Maybe you want to add watermark to PDF thumbnail for a specific PDF file</p>
<pre><code>add_filter( 'pdf_thumbnail_imagick', function( $imagick, $pdf_id ){
    if( $pdf_id == 123 ){
        // add your watermark here
    }
    return $imagick;
}, 10, 2 );
</code></pre>
<h3>get_pdf_thumbnail_image_attributes</h3>
<p>Maybe you want to change attributes for image tag from <code>get_pdf_thumbnail_image</code> function</p>
<pre><code>add_filter( 'get_pdf_thumbnail_image_attributes', function( $attr, $pdf_id ){
    $attr['loading'] = 'eager';
    return $attr;
}, 10, 2 );
</code></pre>
<h3>pdf_thumbnail_generated</h3>
<p>Maybe you want to do something after the thumbnail is generated</p>
<pre><code>add_action( 'pdf_thumbnail_generated', function( $thumbnail_path, $pdf_id ){
    // do somthing with the local file $thumbnail_path
}, 10, 2 );
</code></pre>


PDF Thumbnail Generator


I've used this on multiple sites and have found it invaluable.



While I've struggled with getting the required ImageMagick set up and working on a few servers – each one requiring a slightly different approach owing to different OS and security settings – this is not the fault of the plugin or plugin author.



I'm not sure what one reviewer means by this being built-in to WordPress; to the best of my knowledge that is incorrect.


PDF Thumbnails vs PDF Thumbnail Generator