PHP

Pixel’s public hooks, with an example for each. Their parameters and return values are in the hooks reference, generated from the code.

Several filters receive the image design being rendered, with its settings, elements, other and locations, but not the image’s ID. To target one image, compare its name, settings.name, which is the name you gave it in the image library.

Conditions

sleekPixel/conditions adds conditions to the Conditions view. Each needs an id, a label and a value computed for the current request; an id that starts with is or has makes a boolean condition. Use lowercase IDs, because the editor stores them lowercased.

add_filter('sleekPixel/conditions', function ($conditions) {
  $conditions[] = [
    'id' => 'is_campaign',
    'label' => 'Is campaign link',
    'value' => isset($_GET['campaign']),
  ];

  return $conditions;
});

Data

sleekPixel/data changes the dynamic data before an image uses it. The second argument holds postId, the post being rendered, and the image design.

add_filter('sleekPixel/data', function ($data, $args) {
  $imageName = $args['settings']['name'] ?? '';

  // Change the post title for one image only.
  if ($imageName === 'Blog post card') {
    $data['post']['title'] = 'New Post Title';
  }

  return $data;
}, 10, 2);

Custom data

sleekPixel/data/custom adds entries to the Custom group of the dynamic data. Custom data has an example and the rules the entries follow.

Element data

sleekPixel/image/element/data changes one element of a design just before it renders. The element holds its type (text, image or section), its data and its styles; the second argument is the image design.

add_filter('sleekPixel/image/element/data', function ($element, $image) {
  $imageName = $image['settings']['name'] ?? '';
  $isText = ($element['type'] ?? '') === 'text';

  // Colour every text element of one image blue.
  if ($imageName === 'Blog post card' && $isText) {
    $element['data']['color']['value'] = '#007bff';
  }

  return $element;
}, 10, 2);

Page output

To write its Open Graph and Twitter Card tags, Pixel buffers a front-end page from wp_head to wp_footer when an image’s Open Graph or Twitter Card conditions match it, or when sleekPixel/buffer/output has a callback. sleekPixel/buffer/output receives that HTML after Pixel has changed it and returns what is sent. When another plugin opened an output buffer after Pixel’s and has not closed it by the end of wp_footer, Pixel leaves both buffers as they are and the page goes out unchanged.

add_filter('sleekPixel/buffer/output', function ($html) {
  return str_replace('</head>', "<!-- Images by Pixel -->\n</head>", $html);
});

Init

sleekPixel/init fires once after Pixel has booted, with the plugin instance that sleekPixel() also returns.

add_action('sleekPixel/init', function ($pixel) {
  // Pixel's post types, shortcode and commands are registered.
});