wp_get_attachment_image_srcset()

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概述

wp_get_attachment_image_srcset() 函数用于获取图像附件的 'srcset' 属性值，支持响应式图像处理。它基于附件 ID、图像尺寸和元数据计算并返回 srcset 字符串，若失败则返回 false。

关键要点

函数返回图像附件的 'srcset' 属性值字符串，失败时返回 false
参数包括：$attachment_id（必需，附件 ID）、$size（可选，图像尺寸，默认为 'medium'）、$image_meta（可选，图像元数据）
内部调用 wp_calculate_image_srcset() 进行计算，依赖 wp_get_attachment_image_src() 和 wp_get_attachment_metadata()
支持 $size 参数为注册的图像尺寸名称或宽度和高度的像素数组

代码示例

wp_get_attachment_image_srcset( $attachment_id, array( 400, 200 ) );

📄 原文内容

Retrieves the value for an image attachment’s ‘srcset’ attribute.

Description

Parameters

$attachment_idintrequired: Image attachment ID.
$sizestring|int[]optional: Image size. Accepts any registered image size name, or an array of width and height values in pixels (in that order). Default 'medium'.
$image_metaarray|nulloptional: The image meta data as returned by ‘wp_get_attachment_metadata() ‘.

Default:null

Return

string|false A 'srcset' value string or false.

Source

function wp_get_attachment_image_srcset( $attachment_id, $size = 'medium', $image_meta = null ) {
	$image = wp_get_attachment_image_src( $attachment_id, $size );

	if ( ! $image ) {
		return false;
	}

	if ( ! is_array( $image_meta ) ) {
		$image_meta = wp_get_attachment_metadata( $attachment_id );
	}

	$image_src  = $image[0];
	$size_array = array(
		absint( $image[1] ),
		absint( $image[2] ),
	);

	return wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attachment_id );
}

View all references View on Trac View on GitHub

Uses	Description
wp_calculate_image_srcset()`wp-includes/media.php`	A helper function to calculate the image sources to include in a ‘srcset’ attribute.
wp_get_attachment_image_src()`wp-includes/media.php`	Retrieves an image to represent an attachment.
wp_get_attachment_metadata()`wp-includes/post.php`	Retrieves attachment metadata for attachment ID.
absint()`wp-includes/load.php`	Converts a value to non-negative integer.

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Changelog

Version	Description
4.4.0	Introduced.

User Contributed Notes

Skip to note 2 content

Drew Jaynes

9 years ago

You must log in to vote on the helpfulness of this noteVote results for this note: 0You must log in to vote on the helpfulness of this note
Using $size as an array of width and height dimensions:
```
attachment_id, array( 400, 200 ) );
?>
<img src="<?php header_image(); ?>" srcset="<?php echo esc_attr( $srcset ); ?>">
```
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