wp_calculate_image_srcset

函式
wp_calculate_image_srcset ( $size_array, $image_src, $image_meta, $attachment_id = 0 )
引數
  • (int[]) $size_array { An array of width and height values. @type int $0 The width in pixels. @type int $1 The height in pixels. }
    Required:
  • (string) $image_src The 'src' of the image.
    Required:
  • (array) $image_meta The image meta data as returned by 'wp_get_attachment_metadata()'.
    Required:
  • (int) $attachment_id Optional. The image attachment ID. Default 0.
    Required:
返回值
  • (string|false) The 'srcset' attribute value. False on error or when only one source exists.
定義位置
相關方法
wp_calculate_image_sizeswp_get_attachment_image_srcsetwp_update_image_subsizeswp_create_image_subsizeswp_get_attachment_image_src
引入
4.4.0
棄用
-

wp_calculate_image_srcset: 這個函式根據影象標籤的尺寸和可用的影象大小計算其srcset屬性。

一個輔助函式,用於計算包含在’srcset’屬性中的圖片來源。

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EnlighterJS 3 Syntax Highlighter
function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attachment_id = 0 ) {
/**
* Pre-filters the image meta to be able to fix inconsistencies in the stored data.
*
* @since 4.5.0
*
* @param array $image_meta The image meta data as returned by 'wp_get_attachment_metadata()'.
* @param int[] $size_array {
* An array of requested width and height values.
*
* @type int $0 The width in pixels.
* @type int $1 The height in pixels.
* }
* @param string $image_src The 'src' of the image.
* @param int $attachment_id The image attachment ID or 0 if not supplied.
*/
$image_meta = apply_filters( 'wp_calculate_image_srcset_meta', $image_meta, $size_array, $image_src, $attachment_id );
if ( empty( $image_meta['sizes'] ) || ! isset( $image_meta['file'] ) || strlen( $image_meta['file'] ) < 4 ) {
return false;
}
$image_sizes = $image_meta['sizes'];
// Get the width and height of the image.
$image_width = (int) $size_array[0];
$image_height = (int) $size_array[1];
// Bail early if error/no width.
if ( $image_width < 1 ) {
return false;
}
$image_basename = wp_basename( $image_meta['file'] );
/*
* WordPress flattens animated GIFs into one frame when generating intermediate sizes.
* To avoid hiding animation in user content, if src is a full size GIF, a srcset attribute is not generated.
* If src is an intermediate size GIF, the full size is excluded from srcset to keep a flattened GIF from becoming animated.
*/
if ( ! isset( $image_sizes['thumbnail']['mime-type'] ) || 'image/gif' !== $image_sizes['thumbnail']['mime-type'] ) {
$image_sizes[] = array(
'width' => $image_meta['width'],
'height' => $image_meta['height'],
'file' => $image_basename,
);
} elseif ( strpos( $image_src, $image_meta['file'] ) ) {
return false;
}
// Retrieve the uploads sub-directory from the full size image.
$dirname = _wp_get_attachment_relative_path( $image_meta['file'] );
if ( $dirname ) {
$dirname = trailingslashit( $dirname );
}
$upload_dir = wp_get_upload_dir();
$image_baseurl = trailingslashit( $upload_dir['baseurl'] ) . $dirname;
/*
* If currently on HTTPS, prefer HTTPS URLs when we know they're supported by the domain
* (which is to say, when they share the domain name of the current request).
*/
if ( is_ssl() && 'https' !== substr( $image_baseurl, 0, 5 ) && parse_url( $image_baseurl, PHP_URL_HOST ) === $_SERVER['HTTP_HOST'] ) {
$image_baseurl = set_url_scheme( $image_baseurl, 'https' );
}
/*
* Images that have been edited in WordPress after being uploaded will
* contain a unique hash. Look for that hash and use it later to filter
* out images that are leftovers from previous versions.
*/
$image_edited = preg_match( '/-e[0-9]{13}/', wp_basename( $image_src ), $image_edit_hash );
/**
* Filters 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 '2048'.
* @param int[] $size_array {
* An array of requested width and height values.
*
* @type int $0 The width in pixels.
* @type int $1 The height in pixels.
* }
*/
$max_srcset_image_width = apply_filters( 'max_srcset_image_width', 2048, $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 = true;
$is_src = true;
}
// Filter out images that are from previous edits.
if ( $image_edited && ! strpos( $image['file'], $image_edit_hash[0] ) ) {
continue;
}
/*
* Filters out images that are wider than '$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;
}
// If the image dimensions are within 1px of the expected size, use it.
if ( wp_image_matches_ratio( $image_width, $image_height, $image['width'], $image['height'] ) ) {
// 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;
}
}
}
/**
* Filters 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 {
* An array of requested width and height values.
*
* @type int $0 The width in pixels.
* @type int $1 The height in pixels.
* }
* @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 || ! is_array( $sources ) || count( $sources ) < 2 ) {
return false;
}
$srcset = '';
foreach ( $sources as $source ) {
$srcset .= str_replace( ' ', '%20', $source['url'] ) . ' ' . $source['value'] . $source['descriptor'] . ', ';
}
return rtrim( $srcset, ', ' );
}
function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attachment_id = 0 ) { /** * Pre-filters the image meta to be able to fix inconsistencies in the stored data. * * @since 4.5.0 * * @param array $image_meta The image meta data as returned by 'wp_get_attachment_metadata()'. * @param int[] $size_array { * An array of requested width and height values. * * @type int $0 The width in pixels. * @type int $1 The height in pixels. * } * @param string $image_src The 'src' of the image. * @param int $attachment_id The image attachment ID or 0 if not supplied. */ $image_meta = apply_filters( 'wp_calculate_image_srcset_meta', $image_meta, $size_array, $image_src, $attachment_id ); if ( empty( $image_meta['sizes'] ) || ! isset( $image_meta['file'] ) || strlen( $image_meta['file'] ) < 4 ) { return false; } $image_sizes = $image_meta['sizes']; // Get the width and height of the image. $image_width = (int) $size_array[0]; $image_height = (int) $size_array[1]; // Bail early if error/no width. if ( $image_width < 1 ) { return false; } $image_basename = wp_basename( $image_meta['file'] ); /* * WordPress flattens animated GIFs into one frame when generating intermediate sizes. * To avoid hiding animation in user content, if src is a full size GIF, a srcset attribute is not generated. * If src is an intermediate size GIF, the full size is excluded from srcset to keep a flattened GIF from becoming animated. */ if ( ! isset( $image_sizes['thumbnail']['mime-type'] ) || 'image/gif' !== $image_sizes['thumbnail']['mime-type'] ) { $image_sizes[] = array( 'width' => $image_meta['width'], 'height' => $image_meta['height'], 'file' => $image_basename, ); } elseif ( strpos( $image_src, $image_meta['file'] ) ) { return false; } // Retrieve the uploads sub-directory from the full size image. $dirname = _wp_get_attachment_relative_path( $image_meta['file'] ); if ( $dirname ) { $dirname = trailingslashit( $dirname ); } $upload_dir = wp_get_upload_dir(); $image_baseurl = trailingslashit( $upload_dir['baseurl'] ) . $dirname; /* * If currently on HTTPS, prefer HTTPS URLs when we know they're supported by the domain * (which is to say, when they share the domain name of the current request). */ if ( is_ssl() && 'https' !== substr( $image_baseurl, 0, 5 ) && parse_url( $image_baseurl, PHP_URL_HOST ) === $_SERVER['HTTP_HOST'] ) { $image_baseurl = set_url_scheme( $image_baseurl, 'https' ); } /* * Images that have been edited in WordPress after being uploaded will * contain a unique hash. Look for that hash and use it later to filter * out images that are leftovers from previous versions. */ $image_edited = preg_match( '/-e[0-9]{13}/', wp_basename( $image_src ), $image_edit_hash ); /** * Filters 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 '2048'. * @param int[] $size_array { * An array of requested width and height values. * * @type int $0 The width in pixels. * @type int $1 The height in pixels. * } */ $max_srcset_image_width = apply_filters( 'max_srcset_image_width', 2048, $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 = true; $is_src = true; } // Filter out images that are from previous edits. if ( $image_edited && ! strpos( $image['file'], $image_edit_hash[0] ) ) { continue; } /* * Filters out images that are wider than '$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; } // If the image dimensions are within 1px of the expected size, use it. if ( wp_image_matches_ratio( $image_width, $image_height, $image['width'], $image['height'] ) ) { // 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; } } } /** * Filters 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 { * An array of requested width and height values. * * @type int $0 The width in pixels. * @type int $1 The height in pixels. * } * @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 || ! is_array( $sources ) || count( $sources ) < 2 ) { return false; } $srcset = ''; foreach ( $sources as $source ) { $srcset .= str_replace( ' ', '%20', $source['url'] ) . ' ' . $source['value'] . $source['descriptor'] . ', '; } return rtrim( $srcset, ', ' ); }
function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attachment_id = 0 ) {
	/**
	 * Pre-filters the image meta to be able to fix inconsistencies in the stored data.
	 *
	 * @since 4.5.0
	 *
	 * @param array  $image_meta    The image meta data as returned by 'wp_get_attachment_metadata()'.
	 * @param int[]  $size_array    {
	 *     An array of requested width and height values.
	 *
	 *     @type int $0 The width in pixels.
	 *     @type int $1 The height in pixels.
	 * }
	 * @param string $image_src     The 'src' of the image.
	 * @param int    $attachment_id The image attachment ID or 0 if not supplied.
	 */
	$image_meta = apply_filters( 'wp_calculate_image_srcset_meta', $image_meta, $size_array, $image_src, $attachment_id );

	if ( empty( $image_meta['sizes'] ) || ! isset( $image_meta['file'] ) || strlen( $image_meta['file'] ) < 4 ) {
		return false;
	}

	$image_sizes = $image_meta['sizes'];

	// Get the width and height of the image.
	$image_width  = (int) $size_array[0];
	$image_height = (int) $size_array[1];

	// Bail early if error/no width.
	if ( $image_width < 1 ) {
		return false;
	}

	$image_basename = wp_basename( $image_meta['file'] );

	/*
	 * WordPress flattens animated GIFs into one frame when generating intermediate sizes.
	 * To avoid hiding animation in user content, if src is a full size GIF, a srcset attribute is not generated.
	 * If src is an intermediate size GIF, the full size is excluded from srcset to keep a flattened GIF from becoming animated.
	 */
	if ( ! isset( $image_sizes['thumbnail']['mime-type'] ) || 'image/gif' !== $image_sizes['thumbnail']['mime-type'] ) {
		$image_sizes[] = array(
			'width'  => $image_meta['width'],
			'height' => $image_meta['height'],
			'file'   => $image_basename,
		);
	} elseif ( strpos( $image_src, $image_meta['file'] ) ) {
		return false;
	}

	// Retrieve the uploads sub-directory from the full size image.
	$dirname = _wp_get_attachment_relative_path( $image_meta['file'] );

	if ( $dirname ) {
		$dirname = trailingslashit( $dirname );
	}

	$upload_dir    = wp_get_upload_dir();
	$image_baseurl = trailingslashit( $upload_dir['baseurl'] ) . $dirname;

	/*
	 * If currently on HTTPS, prefer HTTPS URLs when we know they're supported by the domain
	 * (which is to say, when they share the domain name of the current request).
	 */
	if ( is_ssl() && 'https' !== substr( $image_baseurl, 0, 5 ) && parse_url( $image_baseurl, PHP_URL_HOST ) === $_SERVER['HTTP_HOST'] ) {
		$image_baseurl = set_url_scheme( $image_baseurl, 'https' );
	}

	/*
	 * Images that have been edited in WordPress after being uploaded will
	 * contain a unique hash. Look for that hash and use it later to filter
	 * out images that are leftovers from previous versions.
	 */
	$image_edited = preg_match( '/-e[0-9]{13}/', wp_basename( $image_src ), $image_edit_hash );

	/**
	 * Filters 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 '2048'.
	 * @param int[] $size_array {
	 *     An array of requested width and height values.
	 *
	 *     @type int $0 The width in pixels.
	 *     @type int $1 The height in pixels.
	 * }
	 */
	$max_srcset_image_width = apply_filters( 'max_srcset_image_width', 2048, $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 = true;
			$is_src      = true;
		}

		// Filter out images that are from previous edits.
		if ( $image_edited && ! strpos( $image['file'], $image_edit_hash[0] ) ) {
			continue;
		}

		/*
		 * Filters 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;
		}

		// If the image dimensions are within 1px of the expected size, use it.
		if ( wp_image_matches_ratio( $image_width, $image_height, $image['width'], $image['height'] ) ) {
			// 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;
			}
		}
	}

	/**
	 * Filters 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     {
	 *     An array of requested width and height values.
	 *
	 *     @type int $0 The width in pixels.
	 *     @type int $1 The height in pixels.
	 * }
	 * @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 || ! is_array( $sources ) || count( $sources ) < 2 ) {
		return false;
	}

	$srcset = '';

	foreach ( $sources as $source ) {
		$srcset .= str_replace( ' ', '%20', $source['url'] ) . ' ' . $source['value'] . $source['descriptor'] . ', ';
	}

	return rtrim( $srcset, ', ' );
}

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