
如何用React.js创建一个无头的WordPress网站
wp_get_attachment_image ( $attachment_id, $size = 'thumbnail', $icon = false, $attr = '' )
wp_get_attachment_image: 此函数为一个特定的图像附件返回一个HTML img元素。
获取一个代表图片附件的HTML img元素。
虽然`$size`可以接受一个数组,但最好用add_image_size()注册一个尺寸,这样就会生成一个裁剪过的版本。这比找到最接近的图片,然后让浏览器缩小图片的尺寸要有效得多。
function wp_get_attachment_image( $attachment_id, $size = 'thumbnail', $icon = false, $attr = '' ) { $html = ''; $image = wp_get_attachment_image_src( $attachment_id, $size, $icon ); if ( $image ) { list( $src, $width, $height ) = $image; $attachment = get_post( $attachment_id ); $hwstring = image_hwstring( $width, $height ); $size_class = $size; if ( is_array( $size_class ) ) { $size_class = implode( 'x', $size_class ); } $default_attr = array( 'src' => $src, 'class' => "attachment-$size_class size-$size_class", 'alt' => trim( strip_tags( get_post_meta( $attachment_id, '_wp_attachment_image_alt', true ) ) ), 'decoding' => 'async', ); // Add `loading` attribute. if ( wp_lazy_loading_enabled( 'img', 'wp_get_attachment_image' ) ) { $default_attr['loading'] = wp_get_loading_attr_default( 'wp_get_attachment_image' ); } $attr = wp_parse_args( $attr, $default_attr ); // If the default value of `lazy` for the `loading` attribute is overridden // to omit the attribute for this image, ensure it is not included. if ( array_key_exists( 'loading', $attr ) && ! $attr['loading'] ) { unset( $attr['loading'] ); } // Generate 'srcset' and 'sizes' if not already present. if ( empty( $attr['srcset'] ) ) { $image_meta = wp_get_attachment_metadata( $attachment_id ); if ( is_array( $image_meta ) ) { $size_array = array( absint( $width ), absint( $height ) ); $srcset = wp_calculate_image_srcset( $size_array, $src, $image_meta, $attachment_id ); $sizes = wp_calculate_image_sizes( $size_array, $src, $image_meta, $attachment_id ); if ( $srcset && ( $sizes || ! empty( $attr['sizes'] ) ) ) { $attr['srcset'] = $srcset; if ( empty( $attr['sizes'] ) ) { $attr['sizes'] = $sizes; } } } } /** * Filters the list of attachment image attributes. * * @since 2.8.0 * * @param string[] $attr Array of attribute values for the image markup, keyed by attribute name. * See wp_get_attachment_image(). * @param WP_Post $attachment Image attachment post. * @param string|int[] $size Requested image size. Can be any registered image size name, or * an array of width and height values in pixels (in that order). */ $attr = apply_filters( 'wp_get_attachment_image_attributes', $attr, $attachment, $size ); $attr = array_map( 'esc_attr', $attr ); $html = rtrim( "<img $hwstring" ); foreach ( $attr as $name => $value ) { $html .= " $name=" . '"' . $value . '"'; } $html .= ' />'; } /** * Filters the HTML img element representing an image attachment. * * @since 5.6.0 * * @param string $html HTML img element or empty string on failure. * @param int $attachment_id Image attachment ID. * @param string|int[] $size Requested image size. Can be any registered image size name, or * an array of width and height values in pixels (in that order). * @param bool $icon Whether the image should be treated as an icon. * @param string[] $attr Array of attribute values for the image markup, keyed by attribute name. * See wp_get_attachment_image(). */ return apply_filters( 'wp_get_attachment_image', $html, $attachment_id, $size, $icon, $attr ); }