+ /**
+ * Filter the maximum image width to be included in a 'srcset' attribute.
+ *
+ * @since 4.4.0
+ *
+ * @param int $max_width The maximum image width to be included in the 'srcset'. Default '1600'.
+ * @param array $size_array Array of width and height values in pixels (in that order).
+ */
+ $max_srcset_image_width = apply_filters( 'max_srcset_image_width', 1600, $size_array );
+
+ // Array to hold URL candidates.
+ $sources = array();
+
+ /**
+ * To make sure the ID matches our image src, we will check to see if any sizes in our attachment
+ * meta match our $image_src. If no matches are found we don't return a srcset to avoid serving
+ * an incorrect image. See #35045.
+ */
+ $src_matched = false;
+
+ /*
+ * Loop through available images. Only use images that are resized
+ * versions of the same edit.
+ */
+ foreach ( $image_sizes as $image ) {
+ $is_src = false;
+
+ // Check if image meta isn't corrupted.
+ if ( ! is_array( $image ) ) {
+ continue;
+ }
+
+ // If the file name is part of the `src`, we've confirmed a match.
+ if ( ! $src_matched && false !== strpos( $image_src, $dirname . $image['file'] ) ) {
+ $src_matched = $is_src = true;
+ }
+
+ // Filter out images that are from previous edits.
+ if ( $image_edited && ! strpos( $image['file'], $image_edit_hash[0] ) ) {
+ continue;
+ }
+
+ /*
+ * Filter out images that are wider than '$max_srcset_image_width' unless
+ * that file is in the 'src' attribute.
+ */
+ if ( $max_srcset_image_width && $image['width'] > $max_srcset_image_width && ! $is_src ) {
+ continue;
+ }
+
+ /**
+ * To check for varying crops, we calculate the expected size of the smaller
+ * image if the larger were constrained by the width of the smaller and then
+ * see if it matches what we're expecting.
+ */
+ if ( $image_width > $image['width'] ) {
+ $constrained_size = wp_constrain_dimensions( $image_width, $image_height, $image['width'] );
+ $expected_size = array( $image['width'], $image['height'] );
+ } else {
+ $constrained_size = wp_constrain_dimensions( $image['width'], $image['height'], $image_width );
+ $expected_size = array( $image_width, $image_height );
+ }
+
+ // If the image dimensions are within 1px of the expected size, use it.
+ if ( abs( $constrained_size[0] - $expected_size[0] ) <= 1 && abs( $constrained_size[1] - $expected_size[1] ) <= 1 ) {
+ // Add the URL, descriptor, and value to the sources array to be returned.
+ $source = array(
+ 'url' => $image_baseurl . $image['file'],
+ 'descriptor' => 'w',
+ 'value' => $image['width'],
+ );
+
+ // The 'src' image has to be the first in the 'srcset', because of a bug in iOS8. See #35030.
+ if ( $is_src ) {
+ $sources = array( $image['width'] => $source ) + $sources;
+ } else {
+ $sources[ $image['width'] ] = $source;
+ }
+ }
+ }
+
+ /**
+ * Filter an image's 'srcset' sources.
+ *
+ * @since 4.4.0
+ *
+ * @param array $sources {
+ * One or more arrays of source data to include in the 'srcset'.
+ *
+ * @type array $width {
+ * @type string $url The URL of an image source.
+ * @type string $descriptor The descriptor type used in the image candidate string,
+ * either 'w' or 'x'.
+ * @type int $value The source width if paired with a 'w' descriptor, or a
+ * pixel density value if paired with an 'x' descriptor.
+ * }
+ * }
+ * @param array $size_array Array of width and height values in pixels (in that order).
+ * @param string $image_src The 'src' of the image.
+ * @param array $image_meta The image meta data as returned by 'wp_get_attachment_metadata()'.
+ * @param int $attachment_id Image attachment ID or 0.
+ */
+ $sources = apply_filters( 'wp_calculate_image_srcset', $sources, $size_array, $image_src, $image_meta, $attachment_id );
+
+ // Only return a 'srcset' value if there is more than one source.
+ if ( ! $src_matched || count( $sources ) < 2 ) {
+ return false;
+ }
+
+ $srcset = '';
+
+ foreach ( $sources as $source ) {
+ $srcset .= $source['url'] . ' ' . $source['value'] . $source['descriptor'] . ', ';
+ }
+
+ return rtrim( $srcset, ', ' );
+}
+
+/**
+ * Retrieves the value for an image attachment's 'sizes' attribute.
+ *
+ * @since 4.4.0
+ *
+ * @see wp_calculate_image_sizes()
+ *
+ * @param int $attachment_id Image attachment ID.
+ * @param array|string $size Optional. Image size. Accepts any valid image size, or an array of width
+ * and height values in pixels (in that order). Default 'medium'.
+ * @param array $image_meta Optional. The image meta data as returned by 'wp_get_attachment_metadata()'.
+ * Default null.
+ * @return string|bool A valid source size value for use in a 'sizes' attribute or false.
+ */
+function wp_get_attachment_image_sizes( $attachment_id, $size = 'medium', $image_meta = null ) {
+ if ( ! $image = wp_get_attachment_image_src( $attachment_id, $size ) ) {
+ return false;
+ }
+
+ if ( ! is_array( $image_meta ) ) {
+ $image_meta = get_post_meta( $attachment_id, '_wp_attachment_metadata', true );
+ }
+
+ $image_src = $image[0];
+ $size_array = array(
+ absint( $image[1] ),
+ absint( $image[2] )
+ );
+
+ return wp_calculate_image_sizes( $size_array, $image_src, $image_meta, $attachment_id );
+}
+
+/**
+ * Creates a 'sizes' attribute value for an image.
+ *
+ * @since 4.4.0
+ *
+ * @param array|string $size Image size to retrieve. Accepts any valid image size, or an array
+ * of width and height values in pixels (in that order). Default 'medium'.
+ * @param string $image_src Optional. The URL to the image file. Default null.
+ * @param array $image_meta Optional. The image meta data as returned by 'wp_get_attachment_metadata()'.
+ * Default null.
+ * @param int $attachment_id Optional. Image attachment ID. Either `$image_meta` or `$attachment_id`
+ * is needed when using the image size name as argument for `$size`. Default 0.
+ * @return string|bool A valid source size value for use in a 'sizes' attribute or false.
+ */
+function wp_calculate_image_sizes( $size, $image_src = null, $image_meta = null, $attachment_id = 0 ) {
+ $width = 0;
+
+ if ( is_array( $size ) ) {
+ $width = absint( $size[0] );
+ } elseif ( is_string( $size ) ) {
+ if ( ! $image_meta && $attachment_id ) {
+ $image_meta = get_post_meta( $attachment_id, '_wp_attachment_metadata', true );
+ }
+
+ if ( is_array( $image_meta ) ) {
+ $size_array = _wp_get_image_size_from_meta( $size, $image_meta );
+ if ( $size_array ) {
+ $width = absint( $size_array[0] );
+ }
+ }
+ }
+
+ if ( ! $width ) {
+ return false;
+ }
+
+ // Setup the default 'sizes' attribute.
+ $sizes = sprintf( '(max-width: %1$dpx) 100vw, %1$dpx', $width );
+
+ /**
+ * Filter the output of 'wp_calculate_image_sizes()'.
+ *
+ * @since 4.4.0
+ *
+ * @param string $sizes A source size value for use in a 'sizes' attribute.
+ * @param array|string $size Requested size. Image size or array of width and height values
+ * in pixels (in that order).
+ * @param string|null $image_src The URL to the image file or null.
+ * @param array|null $image_meta The image meta data as returned by wp_get_attachment_metadata() or null.
+ * @param int $attachment_id Image attachment ID of the original image or 0.
+ */
+ return apply_filters( 'wp_calculate_image_sizes', $sizes, $size, $image_src, $image_meta, $attachment_id );
+}
+
+/**
+ * Filters 'img' elements in post content to add 'srcset' and 'sizes' attributes.
+ *
+ * @since 4.4.0
+ *
+ * @see wp_image_add_srcset_and_sizes()
+ *
+ * @param string $content The raw post content to be filtered.
+ * @return string Converted content with 'srcset' and 'sizes' attributes added to images.
+ */
+function wp_make_content_images_responsive( $content ) {
+ if ( ! preg_match_all( '/<img [^>]+>/', $content, $matches ) ) {
+ return $content;
+ }
+
+ $selected_images = $attachment_ids = array();
+
+ foreach( $matches[0] as $image ) {
+ if ( false === strpos( $image, ' srcset=' ) && preg_match( '/wp-image-([0-9]+)/i', $image, $class_id ) &&
+ ( $attachment_id = absint( $class_id[1] ) ) ) {
+
+ /*
+ * If exactly the same image tag is used more than once, overwrite it.
+ * All identical tags will be replaced later with 'str_replace()'.
+ */
+ $selected_images[ $image ] = $attachment_id;
+ // Overwrite the ID when the same image is included more than once.
+ $attachment_ids[ $attachment_id ] = true;
+ }
+ }
+
+ if ( count( $attachment_ids ) > 1 ) {
+ /*
+ * Warm object cache for use with 'get_post_meta()'.
+ *
+ * To avoid making a database call for each image, a single query
+ * warms the object cache with the meta information for all images.
+ */
+ update_meta_cache( 'post', array_keys( $attachment_ids ) );
+ }
+
+ foreach ( $selected_images as $image => $attachment_id ) {
+ $image_meta = get_post_meta( $attachment_id, '_wp_attachment_metadata', true );
+ $content = str_replace( $image, wp_image_add_srcset_and_sizes( $image, $image_meta, $attachment_id ), $content );
+ }
+
+ return $content;
+}
+
+/**
+ * Adds 'srcset' and 'sizes' attributes to an existing 'img' element.
+ *
+ * @since 4.4.0
+ *
+ * @see wp_calculate_image_srcset()
+ * @see wp_calculate_image_sizes()
+ *
+ * @param string $image An HTML 'img' element to be filtered.
+ * @param array $image_meta The image meta data as returned by 'wp_get_attachment_metadata()'.
+ * @param int $attachment_id Image attachment ID.
+ * @return string Converted 'img' element with 'srcset' and 'sizes' attributes added.
+ */
+function wp_image_add_srcset_and_sizes( $image, $image_meta, $attachment_id ) {
+ // Ensure the image meta exists.
+ if ( empty( $image_meta['sizes'] ) ) {
+ return $image;
+ }
+
+ $image_src = preg_match( '/src="([^"]+)"/', $image, $match_src ) ? $match_src[1] : '';
+ list( $image_src ) = explode( '?', $image_src );
+
+ // Return early if we couldn't get the image source.
+ if ( ! $image_src ) {
+ return $image;
+ }
+
+ // Bail early if an image has been inserted and later edited.
+ if ( preg_match( '/-e[0-9]{13}/', $image_meta['file'], $img_edit_hash ) &&
+ strpos( wp_basename( $image_src ), $img_edit_hash[0] ) === false ) {
+
+ return $image;
+ }
+
+ $width = preg_match( '/ width="([0-9]+)"/', $image, $match_width ) ? (int) $match_width[1] : 0;
+ $height = preg_match( '/ height="([0-9]+)"/', $image, $match_height ) ? (int) $match_height[1] : 0;
+
+ if ( ! $width || ! $height ) {
+ /*
+ * If attempts to parse the size value failed, attempt to use the image meta data to match
+ * the image file name from 'src' against the available sizes for an attachment.
+ */
+ $image_filename = wp_basename( $image_src );
+
+ if ( $image_filename === wp_basename( $image_meta['file'] ) ) {
+ $width = (int) $image_meta['width'];
+ $height = (int) $image_meta['height'];
+ } else {
+ foreach( $image_meta['sizes'] as $image_size_data ) {
+ if ( $image_filename === $image_size_data['file'] ) {
+ $width = (int) $image_size_data['width'];
+ $height = (int) $image_size_data['height'];
+ break;
+ }
+ }
+ }
+ }
+
+ if ( ! $width || ! $height ) {
+ return $image;
+ }
+
+ $size_array = array( $width, $height );
+ $srcset = wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attachment_id );
+
+ if ( $srcset ) {
+ // Check if there is already a 'sizes' attribute.
+ $sizes = strpos( $image, ' sizes=' );
+
+ if ( ! $sizes ) {
+ $sizes = wp_calculate_image_sizes( $size_array, $image_src, $image_meta, $attachment_id );
+ }
+ }
+
+ if ( $srcset && $sizes ) {
+ // Format the 'srcset' and 'sizes' string and escape attributes.
+ $attr = sprintf( ' srcset="%s"', esc_attr( $srcset ) );
+
+ if ( is_string( $sizes ) ) {
+ $attr .= sprintf( ' sizes="%s"', esc_attr( $sizes ) );
+ }
+
+ // Add 'srcset' and 'sizes' attributes to the image markup.
+ $image = preg_replace( '/<img ([^>]+?)[\/ ]*>/', '<img $1' . $attr . ' />', $image );
+ }
+
+ return $image;
+}
+
+/**
+ * Adds a 'wp-post-image' class to post thumbnails. Internal use only.
+ *
+ * Uses the 'begin_fetch_post_thumbnail_html' and 'end_fetch_post_thumbnail_html' action hooks to
+ * dynamically add/remove itself so as to only filter post thumbnails.
+ *
+ * @ignore
+ * @since 2.9.0
+ *
+ * @param array $attr Thumbnail attributes including src, class, alt, title.
+ * @return array Modified array of attributes including the new 'wp-post-image' class.
+ */
+function _wp_post_thumbnail_class_filter( $attr ) {
+ $attr['class'] .= ' wp-post-image';
+ return $attr;
+}
+
+/**
+ * Adds '_wp_post_thumbnail_class_filter' callback to the 'wp_get_attachment_image_attributes'
+ * filter hook. Internal use only.
+ *
+ * @ignore
+ * @since 2.9.0
+ *
+ * @param array $attr Thumbnail attributes including src, class, alt, title.
+ */
+function _wp_post_thumbnail_class_filter_add( $attr ) {
+ add_filter( 'wp_get_attachment_image_attributes', '_wp_post_thumbnail_class_filter' );
+}
+
+/**
+ * Removes the '_wp_post_thumbnail_class_filter' callback from the 'wp_get_attachment_image_attributes'
+ * filter hook. Internal use only.
+ *
+ * @ignore
+ * @since 2.9.0
+ *
+ * @param array $attr Thumbnail attributes including src, class, alt, title.
+ */
+function _wp_post_thumbnail_class_filter_remove( $attr ) {
+ remove_filter( 'wp_get_attachment_image_attributes', '_wp_post_thumbnail_class_filter' );
+}
+
+add_shortcode('wp_caption', 'img_caption_shortcode');
+add_shortcode('caption', 'img_caption_shortcode');
+
+/**
+ * Builds the Caption shortcode output.
+ *
+ * Allows a plugin to replace the content that would otherwise be returned. The
+ * filter is 'img_caption_shortcode' and passes an empty string, the attr
+ * parameter and the content parameter values.
+ *
+ * The supported attributes for the shortcode are 'id', 'align', 'width', and
+ * 'caption'.
+ *
+ * @since 2.6.0
+ *
+ * @param array $attr {
+ * Attributes of the caption shortcode.
+ *
+ * @type string $id ID of the div element for the caption.
+ * @type string $align Class name that aligns the caption. Default 'alignnone'. Accepts 'alignleft',
+ * 'aligncenter', alignright', 'alignnone'.
+ * @type int $width The width of the caption, in pixels.
+ * @type string $caption The caption text.
+ * @type string $class Additional class name(s) added to the caption container.
+ * }
+ * @param string $content Shortcode content.
+ * @return string HTML content to display the caption.
+ */
+function img_caption_shortcode( $attr, $content = null ) {
+ // New-style shortcode with the caption inside the shortcode with the link and image tags.
+ if ( ! isset( $attr['caption'] ) ) {
+ if ( preg_match( '#((?:<a [^>]+>\s*)?<img [^>]+>(?:\s*</a>)?)(.*)#is', $content, $matches ) ) {
+ $content = $matches[1];
+ $attr['caption'] = trim( $matches[2] );
+ }
+ } elseif ( strpos( $attr['caption'], '<' ) !== false ) {
+ $attr['caption'] = wp_kses( $attr['caption'], 'post' );
+ }
+
+ /**
+ * Filter the default caption shortcode output.
+ *
+ * If the filtered output isn't empty, it will be used instead of generating
+ * the default caption template.
+ *
+ * @since 2.6.0
+ *
+ * @see img_caption_shortcode()
+ *
+ * @param string $output The caption output. Default empty.
+ * @param array $attr Attributes of the caption shortcode.
+ * @param string $content The image element, possibly wrapped in a hyperlink.
+ */
+ $output = apply_filters( 'img_caption_shortcode', '', $attr, $content );
+ if ( $output != '' )
+ return $output;
+
+ $atts = shortcode_atts( array(
+ 'id' => '',
+ 'align' => 'alignnone',
+ 'width' => '',
+ 'caption' => '',
+ 'class' => '',
+ ), $attr, 'caption' );
+
+ $atts['width'] = (int) $atts['width'];
+ if ( $atts['width'] < 1 || empty( $atts['caption'] ) )
+ return $content;
+
+ if ( ! empty( $atts['id'] ) )
+ $atts['id'] = 'id="' . esc_attr( sanitize_html_class( $atts['id'] ) ) . '" ';
+
+ $class = trim( 'wp-caption ' . $atts['align'] . ' ' . $atts['class'] );
+
+ $html5 = current_theme_supports( 'html5', 'caption' );
+ // HTML5 captions never added the extra 10px to the image width
+ $width = $html5 ? $atts['width'] : ( 10 + $atts['width'] );
+
+ /**
+ * Filter the width of an image's caption.
+ *
+ * By default, the caption is 10 pixels greater than the width of the image,
+ * to prevent post content from running up against a floated image.
+ *
+ * @since 3.7.0
+ *
+ * @see img_caption_shortcode()
+ *
+ * @param int $width Width of the caption in pixels. To remove this inline style,
+ * return zero.
+ * @param array $atts Attributes of the caption shortcode.
+ * @param string $content The image element, possibly wrapped in a hyperlink.
+ */
+ $caption_width = apply_filters( 'img_caption_shortcode_width', $width, $atts, $content );
+
+ $style = '';
+ if ( $caption_width )
+ $style = 'style="width: ' . (int) $caption_width . 'px" ';
+
+ $html = '';
+ if ( $html5 ) {
+ $html = '<figure ' . $atts['id'] . $style . 'class="' . esc_attr( $class ) . '">'
+ . do_shortcode( $content ) . '<figcaption class="wp-caption-text">' . $atts['caption'] . '</figcaption></figure>';
+ } else {
+ $html = '<div ' . $atts['id'] . $style . 'class="' . esc_attr( $class ) . '">'
+ . do_shortcode( $content ) . '<p class="wp-caption-text">' . $atts['caption'] . '</p></div>';
+ }
+
+ return $html;
+}
+
+add_shortcode('gallery', 'gallery_shortcode');
+
+/**
+ * Builds the Gallery shortcode output.
+ *
+ * This implements the functionality of the Gallery Shortcode for displaying
+ * WordPress images on a post.
+ *
+ * @since 2.5.0
+ *
+ * @staticvar int $instance
+ *
+ * @param array $attr {
+ * Attributes of the gallery shortcode.
+ *
+ * @type string $order Order of the images in the gallery. Default 'ASC'. Accepts 'ASC', 'DESC'.
+ * @type string $orderby The field to use when ordering the images. Default 'menu_order ID'.
+ * Accepts any valid SQL ORDERBY statement.
+ * @type int $id Post ID.
+ * @type string $itemtag HTML tag to use for each image in the gallery.
+ * Default 'dl', or 'figure' when the theme registers HTML5 gallery support.
+ * @type string $icontag HTML tag to use for each image's icon.
+ * Default 'dt', or 'div' when the theme registers HTML5 gallery support.
+ * @type string $captiontag HTML tag to use for each image's caption.
+ * Default 'dd', or 'figcaption' when the theme registers HTML5 gallery support.
+ * @type int $columns Number of columns of images to display. Default 3.
+ * @type string|array $size Size of the images to display. Accepts any valid image size, or an array of width
+ * and height values in pixels (in that order). Default 'thumbnail'.
+ * @type string $ids A comma-separated list of IDs of attachments to display. Default empty.
+ * @type string $include A comma-separated list of IDs of attachments to include. Default empty.
+ * @type string $exclude A comma-separated list of IDs of attachments to exclude. Default empty.
+ * @type string $link What to link each image to. Default empty (links to the attachment page).
+ * Accepts 'file', 'none'.
+ * }
+ * @return string HTML content to display gallery.
+ */
+function gallery_shortcode( $attr ) {
+ $post = get_post();
+
+ static $instance = 0;
+ $instance++;
+
+ if ( ! empty( $attr['ids'] ) ) {
+ // 'ids' is explicitly ordered, unless you specify otherwise.
+ if ( empty( $attr['orderby'] ) ) {
+ $attr['orderby'] = 'post__in';
+ }
+ $attr['include'] = $attr['ids'];
+ }
+
+ /**
+ * Filter the default gallery shortcode output.
+ *
+ * If the filtered output isn't empty, it will be used instead of generating
+ * the default gallery template.
+ *
+ * @since 2.5.0
+ * @since 4.2.0 The `$instance` parameter was added.
+ *
+ * @see gallery_shortcode()
+ *
+ * @param string $output The gallery output. Default empty.
+ * @param array $attr Attributes of the gallery shortcode.
+ * @param int $instance Unique numeric ID of this gallery shortcode instance.
+ */
+ $output = apply_filters( 'post_gallery', '', $attr, $instance );
+ if ( $output != '' ) {
+ return $output;
+ }
+
+ $html5 = current_theme_supports( 'html5', 'gallery' );
+ $atts = shortcode_atts( array(
+ 'order' => 'ASC',
+ 'orderby' => 'menu_order ID',
+ 'id' => $post ? $post->ID : 0,
+ 'itemtag' => $html5 ? 'figure' : 'dl',
+ 'icontag' => $html5 ? 'div' : 'dt',
+ 'captiontag' => $html5 ? 'figcaption' : 'dd',
+ 'columns' => 3,
+ 'size' => 'thumbnail',
+ 'include' => '',
+ 'exclude' => '',
+ 'link' => ''
+ ), $attr, 'gallery' );
+
+ $id = intval( $atts['id'] );
+
+ if ( ! empty( $atts['include'] ) ) {
+ $_attachments = get_posts( array( 'include' => $atts['include'], 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $atts['order'], 'orderby' => $atts['orderby'] ) );
+
+ $attachments = array();
+ foreach ( $_attachments as $key => $val ) {
+ $attachments[$val->ID] = $_attachments[$key];
+ }
+ } elseif ( ! empty( $atts['exclude'] ) ) {
+ $attachments = get_children( array( 'post_parent' => $id, 'exclude' => $atts['exclude'], 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $atts['order'], 'orderby' => $atts['orderby'] ) );
+ } else {
+ $attachments = get_children( array( 'post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $atts['order'], 'orderby' => $atts['orderby'] ) );
+ }
+
+ if ( empty( $attachments ) ) {
+ return '';
+ }