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WP_Widget_Media_Image

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概述

WP_Widget_Media_Image 是 WordPress 核心类，用于实现图像小部件，继承自 WP_Widget_Media。它提供了图像小部件的构造函数、实例属性模式、前端渲染和管理脚本加载等功能。

关键要点

  • 继承自 WP_Widget_Media，专门处理图像媒体类型。
  • 构造函数定义小部件 ID、标题、描述和本地化字符串。
  • get_instance_schema 方法返回实例属性模式，包括尺寸、链接类型、CSS 类等。
  • render_media 方法负责在前端渲染图像，支持附件和外部 URL。
  • enqueue_admin_scripts 方法加载媒体管理器和脚本。
  • render_control_template_scripts 方法渲染表单模板脚本。

代码示例

// 构造函数示例
public function __construct() {
    parent::__construct(
        'media_image',
        __( 'Image' ),
        array(
            'description' => __( 'Displays an image.' ),
            'mime_type'   => 'image',
        )
    );
    // 本地化字符串设置
    $this->l10n = array_merge( $this->l10n, array( ... ) );
}

注意事项

在自定义图像小部件时，需确保正确处理附件和外部 URL 的渲染逻辑，并遵循实例属性模式以保持兼容性。

📄 原文内容

Core class that implements an image widget.

Description

See also

Methods

Name Description
WP_Widget_Media_Image::__construct Constructor.
WP_Widget_Media_Image::enqueue_admin_scripts Loads the required media files for the media manager and scripts for media widgets.
WP_Widget_Media_Image::get_instance_schema Get schema for properties of a widget instance (item).
WP_Widget_Media_Image::render_control_template_scripts Render form template scripts.
WP_Widget_Media_Image::render_media Render the media on the frontend.

Source

class WP_Widget_Media_Image extends WP_Widget_Media {


	/**

	 * Constructor.

	 *

	 * @since 4.8.0

	 */

	public function __construct() {

		parent::__construct(

			'media_image',

			__( 'Image' ),

			array(

				'description' => __( 'Displays an image.' ),

				'mime_type'   => 'image',

			)

		);


		$this->l10n = array_merge(

			$this->l10n,

			array(

				'no_media_selected'          => __( 'No image selected' ),

				'add_media'                  => _x( 'Add Image', 'label for button in the image widget' ),

				'replace_media'              => _x( 'Replace Image', 'label for button in the image widget; should preferably not be longer than ~13 characters long' ),

				'edit_media'                 => _x( 'Edit Image', 'label for button in the image widget; should preferably not be longer than ~13 characters long' ),

				'missing_attachment'         => sprintf(

					/* translators: %s: URL to media library. */

					__( 'That image cannot be found. Check your <a href="%s">media library</a> and make sure it was not deleted.' ),

					esc_url( admin_url( 'upload.php' ) )

				),

				/* translators: %d: Widget count. */

				'media_library_state_multi'  => _n_noop( 'Image Widget (%d)', 'Image Widget (%d)' ),

				'media_library_state_single' => __( 'Image Widget' ),

			)

		);

	}


	/**

	 * Get schema for properties of a widget instance (item).

	 *

	 * @since 4.8.0

	 *

	 * @see WP_REST_Controller::get_item_schema()

	 * @see WP_REST_Controller::get_additional_fields()

	 * @link https://core.trac.wordpress.org/ticket/35574

	 *

	 * @return array Schema for properties.

	 */

	public function get_instance_schema() {

		return array_merge(

			array(

				'size'              => array(

					'type'        => 'string',

					'enum'        => array_merge( get_intermediate_image_sizes(), array( 'full', 'custom' ) ),

					'default'     => 'medium',

					'description' => __( 'Size' ),

				),

				'width'             => array( // Via 'customWidth', only when size=custom; otherwise via 'width'.

					'type'        => 'integer',

					'minimum'     => 0,

					'default'     => 0,

					'description' => __( 'Width' ),

				),

				'height'            => array( // Via 'customHeight', only when size=custom; otherwise via 'height'.

					'type'        => 'integer',

					'minimum'     => 0,

					'default'     => 0,

					'description' => __( 'Height' ),

				),


				'caption'           => array(

					'type'                  => 'string',

					'default'               => '',

					'sanitize_callback'     => 'wp_kses_post',

					'description'           => __( 'Caption' ),

					'should_preview_update' => false,

				),

				'alt'               => array(

					'type'              => 'string',

					'default'           => '',

					'sanitize_callback' => 'sanitize_text_field',

					'description'       => __( 'Alternative Text' ),

				),

				'link_type'         => array(

					'type'                  => 'string',

					'enum'                  => array( 'none', 'file', 'post', 'custom' ),

					'default'               => 'custom',

					'media_prop'            => 'link',

					'description'           => __( 'Link To' ),

					'should_preview_update' => true,

				),

				'link_url'          => array(

					'type'                  => 'string',

					'default'               => '',

					'format'                => 'uri',

					'media_prop'            => 'linkUrl',

					'description'           => __( 'URL' ),

					'should_preview_update' => true,

				),

				'image_classes'     => array(

					'type'                  => 'string',

					'default'               => '',

					'sanitize_callback'     => array( $this, 'sanitize_token_list' ),

					'media_prop'            => 'extraClasses',

					'description'           => __( 'Image CSS Class' ),

					'should_preview_update' => false,

				),

				'link_classes'      => array(

					'type'                  => 'string',

					'default'               => '',

					'sanitize_callback'     => array( $this, 'sanitize_token_list' ),

					'media_prop'            => 'linkClassName',

					'should_preview_update' => false,

					'description'           => __( 'Link CSS Class' ),

				),

				'link_rel'          => array(

					'type'                  => 'string',

					'default'               => '',

					'sanitize_callback'     => array( $this, 'sanitize_token_list' ),

					'media_prop'            => 'linkRel',

					'description'           => __( 'Link Rel' ),

					'should_preview_update' => false,

				),

				'link_target_blank' => array(

					'type'                  => 'boolean',

					'default'               => false,

					'media_prop'            => 'linkTargetBlank',

					'description'           => __( 'Open link in a new tab' ),

					'should_preview_update' => false,

				),

				'image_title'       => array(

					'type'                  => 'string',

					'default'               => '',

					'sanitize_callback'     => 'sanitize_text_field',

					'media_prop'            => 'title',

					'description'           => __( 'Image Title Attribute' ),

					'should_preview_update' => false,

				),


				/*

				 * There are two additional properties exposed by the PostImage modal

				 * that don't seem to be relevant, as they may only be derived read-only

				 * values:

				 * - originalUrl

				 * - aspectRatio

				 * - height (redundant when size is not custom)

				 * - width (redundant when size is not custom)

				 */

			),

			parent::get_instance_schema()

		);

	}


	/**

	 * Render the media on the frontend.

	 *

	 * @since 4.8.0

	 *

	 * @param array $instance Widget instance props.

	 */

	public function render_media( $instance ) {

		$instance = array_merge( wp_list_pluck( $this->get_instance_schema(), 'default' ), $instance );

		$instance = wp_parse_args(

			$instance,

			array(

				'size' => 'thumbnail',

			)

		);


		$attachment = null;


		if ( $this->is_attachment_with_mime_type( $instance['attachment_id'], $this->widget_options['mime_type'] ) ) {

			$attachment = get_post( $instance['attachment_id'] );

		}


		if ( $attachment ) {

			$caption = '';

			if ( ! isset( $instance['caption'] ) ) {

				$caption = $attachment->post_excerpt;

			} elseif ( trim( $instance['caption'] ) ) {

				$caption = $instance['caption'];

			}


			$image_attributes = array(

				'class' => sprintf( 'image wp-image-%d %s', $attachment->ID, $instance['image_classes'] ),

				'style' => 'max-width: 100%; height: auto;',

			);

			if ( ! empty( $instance['image_title'] ) ) {

				$image_attributes['title'] = $instance['image_title'];

			}


			if ( $instance['alt'] ) {

				$image_attributes['alt'] = $instance['alt'];

			}


			$size = $instance['size'];


			if ( 'custom' === $size || ! in_array( $size, array_merge( get_intermediate_image_sizes(), array( 'full' ) ), true ) ) {

				$size  = array( $instance['width'], $instance['height'] );

				$width = $instance['width'];

			} else {

				$caption_size = _wp_get_image_size_from_meta( $instance['size'], wp_get_attachment_metadata( $attachment->ID ) );

				$width        = empty( $caption_size[0] ) ? 0 : $caption_size[0];

			}


			$image_attributes['class'] .= sprintf( ' attachment-%1$s size-%1$s', is_array( $size ) ? implode( 'x', $size ) : $size );


			$image = wp_get_attachment_image( $attachment->ID, $size, false, $image_attributes );


		} else {

			if ( empty( $instance['url'] ) ) {

				return;

			}


			$instance['size'] = 'custom';

			$caption          = $instance['caption'];

			$width            = $instance['width'];

			$classes          = 'image ' . $instance['image_classes'];

			if ( 0 === $instance['width'] ) {

				$instance['width'] = '';

			}

			if ( 0 === $instance['height'] ) {

				$instance['height'] = '';

			}


			$attr = array(

				'class'  => $classes,

				'src'    => $instance['url'],

				'alt'    => $instance['alt'],

				'width'  => $instance['width'],

				'height' => $instance['height'],

			);


			$loading_optimization_attr = wp_get_loading_optimization_attributes(

				'img',

				$attr,

				'widget_media_image'

			);


			$attr = array_merge( $attr, $loading_optimization_attr );


			$attr  = array_map( 'esc_attr', $attr );

			$image = '<img';


			foreach ( $attr as $name => $value ) {

				$image .= ' ' . $name . '="' . $value . '"';

			}


			$image .= ' />';

		} // End if().


		$url = '';

		if ( 'file' === $instance['link_type'] ) {

			$url = $attachment ? wp_get_attachment_url( $attachment->ID ) : $instance['url'];

		} elseif ( $attachment && 'post' === $instance['link_type'] ) {

			$url = get_attachment_link( $attachment->ID );

		} elseif ( 'custom' === $instance['link_type'] && ! empty( $instance['link_url'] ) ) {

			$url = $instance['link_url'];

		}


		if ( $url ) {

			$link = sprintf( '<a href="%s"', esc_url( $url ) );

			if ( ! empty( $instance['link_classes'] ) ) {

				$link .= sprintf( ' class="%s"', esc_attr( $instance['link_classes'] ) );

			}

			if ( ! empty( $instance['link_rel'] ) ) {

				$link .= sprintf( ' rel="%s"', esc_attr( $instance['link_rel'] ) );

			}

			if ( ! empty( $instance['link_target_blank'] ) ) {

				$link .= ' target="_blank"';

			}

			$link .= '>';

			$link .= $image;

			$link .= '</a>';

			$image = $link;

		}


		if ( $caption ) {

			$image = img_caption_shortcode(

				array(

					'width'   => $width,

					'caption' => $caption,

				),

				$image

			);

		}


		echo $image;

	}


	/**

	 * Loads the required media files for the media manager and scripts for media widgets.

	 *

	 * @since 4.8.0

	 */

	public function enqueue_admin_scripts() {

		parent::enqueue_admin_scripts();


		$handle = 'media-image-widget';

		wp_enqueue_script( $handle );


		$exported_schema = array();

		foreach ( $this->get_instance_schema() as $field => $field_schema ) {

			$exported_schema[ $field ] = wp_array_slice_assoc( $field_schema, array( 'type', 'default', 'enum', 'minimum', 'format', 'media_prop', 'should_preview_update' ) );

		}

		wp_add_inline_script(

			$handle,

			sprintf(

				'wp.mediaWidgets.modelConstructors[ %s ].prototype.schema = %s;',

				wp_json_encode( $this->id_base, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),

				wp_json_encode( $exported_schema, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES )

			)

		);


		wp_add_inline_script(

			$handle,

			sprintf(

				'

					wp.mediaWidgets.controlConstructors[ %1$s ].prototype.mime_type = %2$s;

					wp.mediaWidgets.controlConstructors[ %1$s ].prototype.l10n = _.extend( {}, wp.mediaWidgets.controlConstructors[ %1$s ].prototype.l10n, %3$s );

				',

				wp_json_encode( $this->id_base, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),

				wp_json_encode( $this->widget_options['mime_type'], JSON_HEX_TAG | JSON_UNESCAPED_SLASHES ),

				wp_json_encode( $this->l10n, JSON_HEX_TAG | JSON_UNESCAPED_SLASHES )

			)

		);

	}


	/**

	 * Render form template scripts.

	 *

	 * @since 4.8.0

	 */

	public function render_control_template_scripts() {

		parent::render_control_template_scripts();


		?>

		<script type="text/html" id="tmpl-wp-media-widget-image-fields">

			<# var elementIdPrefix = 'el' + String( Math.random() ) + '_'; #>

			<# if ( data.url ) { #>

			<p class="media-widget-image-link">

				<label for="{{ elementIdPrefix }}linkUrl"><?php esc_html_e( 'Link to:' ); ?></label>

				<input id="{{ elementIdPrefix }}linkUrl" type="text" class="widefat link" value="{{ data.link_url }}" placeholder="https://" pattern="((w+:)?//w.*|w+:(?!//$)|/|?|#).*">

			</p>

			<# } #>

		</script>

		<script type="text/html" id="tmpl-wp-media-widget-image-preview">

			<# if ( data.error && 'missing_attachment' === data.error ) { #>

				<?php

				wp_admin_notice(

					$this->l10n['missing_attachment'],

					array(

						'type'               => 'error',

						'additional_classes' => array( 'notice-alt', 'notice-missing-attachment' ),

					)

				);

				?>

			<# } else if ( data.error ) { #>

				<?php

				wp_admin_notice(

					__( 'Unable to preview media due to an unknown error.' ),

					array(

						'type'               => 'error',

						'additional_classes' => array( 'notice-alt' ),

					)

				);

				?>

			<# } else if ( data.url ) { #>

				<img class="attachment-thumb" src="{{ data.url }}" draggable="false" alt="{{ data.alt }}"

					<# if ( ! data.alt && data.currentFilename ) { #>

						aria-label="

						<?php

						echo esc_attr(

							sprintf(

								/* translators: %s: The image file name. */

								__( 'The current image has no alternative text. The file name is: %s' ),

								'{{ data.currentFilename }}'

							)

						);

						?>

						"

					<# } #>

				/>

			<# } #>

		</script>

		</pre><p class="wporg-dot-link-list"><a href="https://developer.wordpress.org/reference/files/wp-includes/widgets/class-wp-widget-media-image.php/">View all references</a> <a href="https://core.trac.wordpress.org/browser/tags/6.9.4/src/wp-includes/widgets/class-wp-widget-media-image.php#L18">View on Trac</a> <a href="https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/widgets/class-wp-widget-media-image.php#L18-L404">View on GitHub</a></p></section>


		<section class="wp-block-wporg-code-reference-related" data-nosnippet="true"><h2 id="related" class="is-toc-heading wp-block-heading has-heading-5-font-size" tabindex="-1" ><a href="#related">Related</a></h2> <section style="margin-top:var(--wp--preset--spacing--20)" class="wp-block-wporg-code-table" id="uses"><figure class="wp-block-table "><table><thead><tr><th scope="col">Uses</th><th scope="col">Description</th></tr></thead><tbody><tr class=""><td><a href="https://developer.wordpress.org/reference/classes/wp_widget_media/">WP_Widget_Media</a><code>wp-includes/widgets/class-wp-widget-media.php


Core class that implements a media widget.

Changelog

Version Description
4.8.0 Introduced.