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wp_image_matches_ratio()

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概述

wp_image_matches_ratio() 是一个辅助函数，用于测试两个图像的宽高比是否匹配。它通过比较图像尺寸，在1像素容差范围内判断宽高比是否一致。

关键要点

  • 函数接受四个整数参数：$source_width、$source_height、$target_width、$target_height，分别表示两个图像的宽度和高度。
  • 返回布尔值：如果宽高比在1像素内匹配则返回 true，否则返回 false。
  • 内部使用 wp_constrain_dimensions() 和 wp_fuzzy_number_match() 函数进行计算和容差判断。
  • 主要用于图像处理场景，如 srcset 属性计算和中间尺寸检索。

代码示例

function wp_image_matches_ratio( $source_width, $source_height, $target_width, $target_height ) {
    if ( $source_width > $target_width ) {
        $constrained_size = wp_constrain_dimensions( $source_width, $source_height, $target_width );
        $expected_size    = array( $target_width, $target_height );
    } else {
        $constrained_size = wp_constrain_dimensions( $target_width, $target_height, $source_width );
        $expected_size    = array( $source_width, $source_height );
    }

    $matched = ( wp_fuzzy_number_match( $constrained_size[0], $expected_size[0] ) && wp_fuzzy_number_match( $constrained_size[1], $expected_size[1] ) );

    return $matched;
}

注意事项

  • 函数自 WordPress 4.6.0 版本引入。
  • 依赖 wp_constrain_dimensions() 和 wp_fuzzy_number_match() 函数，确保这些函数可用。
  • 常用于 wp_calculate_image_srcset() 和 image_get_intermediate_size() 等图像处理函数中。
📄 原文内容

Helper function to test if aspect ratios for two images match.

Parameters

$source_widthintrequired
Width of the first image in pixels.
$source_heightintrequired
Height of the first image in pixels.
$target_widthintrequired
Width of the second image in pixels.
$target_heightintrequired
Height of the second image in pixels.

Return

bool True if aspect ratios match within 1px. False if not.

Source

function wp_image_matches_ratio( $source_width, $source_height, $target_width, $target_height ) {
	/*
	 * To test for varying crops, we constrain the dimensions of the larger image
	 * to the dimensions of the smaller image and see if they match.
	 */
	if ( $source_width > $target_width ) {
		$constrained_size = wp_constrain_dimensions( $source_width, $source_height, $target_width );
		$expected_size    = array( $target_width, $target_height );
	} else {
		$constrained_size = wp_constrain_dimensions( $target_width, $target_height, $source_width );
		$expected_size    = array( $source_width, $source_height );
	}

	// If the image dimensions are within 1px of the expected size, we consider it a match.
	$matched = ( wp_fuzzy_number_match( $constrained_size[0], $expected_size[0] ) && wp_fuzzy_number_match( $constrained_size[1], $expected_size[1] ) );

	return $matched;
}

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Uses Description
wp_fuzzy_number_match()wp-includes/functions.php

Checks if two numbers are nearly the same.
wp_constrain_dimensions()wp-includes/media.php

Calculates the new dimensions for a down-sampled image.
Used by Description
wp_calculate_image_srcset()wp-includes/media.php

A helper function to calculate the image sources to include in a ‘srcset’ attribute.
image_get_intermediate_size()wp-includes/media.php

Retrieves the image’s intermediate size (resized) path, width, and height.

Changelog

Version Description
4.6.0 Introduced.