/**
* Retrieve URL for an attachment thumbnail.
*
* @since 2.1.0
*
* @param int $post_id Attachment ID
* @return string|bool False on failure. Thumbnail URL on success.
*/
function nxt_get_attachment_thumb_url($post_id = 0)
{
$post_id = (int) $post_id;
if (!($post =& get_post($post_id))) {
return false;
}
if (!($url = nxt_get_attachment_url($post->ID))) {
return false;
}
$sized = image_downsize($post_id, 'thumbnail');
if ($sized) {
return $sized[0];
}
if (!($thumb = nxt_get_attachment_thumb_file($post->ID))) {
return false;
}
$url = str_replace(basename($url), basename($thumb), $url);
return apply_filters('nxt_get_attachment_thumb_url', $url, $post->ID);
}
/**
* Scale an image to fit a particular size (such as 'thumb' or 'medium').
*
* Array with image url, width, height, and whether is intermediate size, in
* that order is returned on success is returned. $is_intermediate is true if
* $url is a resized image, false if it is the original.
*
* The URL might be the original image, or it might be a resized version. This
* function won't create a new resized copy, it will just return an already
* resized one if it exists.
*
* A plugin may use the 'image_downsize' filter to hook into and offer image
* resizing services for images. The hook must return an array with the same
* elements that are returned in the function. The first element being the URL
* to the new image that was resized.
*
* @since 2.5.0
* @uses apply_filters() Calls 'image_downsize' on $id and $size to provide
* resize services.
*
* @param int $id Attachment ID for image.
* @param array|string $size Optional, default is 'medium'. Size of image, either array or string.
* @return bool|array False on failure, array on success.
*/
function image_downsize($id, $size = 'medium')
{
if (!nxt_attachment_is_image($id)) {
return false;
}
$img_url = nxt_get_attachment_url($id);
$meta = nxt_get_attachment_metadata($id);
$width = $height = 0;
$is_intermediate = false;
$img_url_basename = nxt_basename($img_url);
// plugins can use this to provide resize services
if ($out = apply_filters('image_downsize', false, $id, $size)) {
return $out;
}
// try for a new style intermediate size
if ($intermediate = image_get_intermediate_size($id, $size)) {
$img_url = str_replace($img_url_basename, $intermediate['file'], $img_url);
$width = $intermediate['width'];
$height = $intermediate['height'];
$is_intermediate = true;
} elseif ($size == 'thumbnail') {
// fall back to the old thumbnail
if (($thumb_file = nxt_get_attachment_thumb_file($id)) && ($info = getimagesize($thumb_file))) {
$img_url = str_replace($img_url_basename, nxt_basename($thumb_file), $img_url);
$width = $info[0];
$height = $info[1];
$is_intermediate = true;
}
}
if (!$width && !$height && isset($meta['width'], $meta['height'])) {
// any other type: use the real image
$width = $meta['width'];
$height = $meta['height'];
}
if ($img_url) {
// we have the actual image size, but might need to further constrain it if content_width is narrower
list($width, $height) = image_constrain_size_for_editor($width, $height, $size);
return array($img_url, $width, $height, $is_intermediate);
}
return false;
}