image_resize_dimensions()

检索计算的调整大小尺寸以在WP_Image_Editor中使用。

原型

image_resize_dimensions( int $orig_w, int $orig_h, int $dest_w, int $dest_h, bool|array $crop = false )

描述

计算适合指定宽度和高度的已调整大小的图像的尺寸和坐标。

参数

$orig_w (int) (Required) 原始宽度（像素）。

$orig_h (int) (Required) 原始高度（像素）。

$dest_w (int) (Required) 新的像素宽度。

$dest_h (int) (Required) 新的像素高度。

$crop (bool|array) (Optional)  是否将图像裁剪为指定的宽度和高度或调整大小。数组可以指定裁剪区域的位置。

返回值

(false|array)  失败时是假的。返回的数组匹配参数

源文件

路径：wp-includes/media.php

<?php
...
function image_resize_dimensions( $orig_w, $orig_h, $dest_w, $dest_h, $crop = false ) {
	if ($orig_w <= 0 || $orig_h <= 0)
		return false;
	// at least one of dest_w or dest_h must be specific
	if ($dest_w <= 0 && $dest_h <= 0)
		return false;
	/**
	 * Filters whether to preempt calculating the image resize dimensions.
	 *
	 * Passing a non-null value to the filter will effectively short-circuit
	 * image_resize_dimensions(), returning that value instead.
	 *
	 * @since 3.4.0
	 *
	 * @param null|mixed $null   Whether to preempt output of the resize dimensions.
	 * @param int        $orig_w Original width in pixels.
	 * @param int        $orig_h Original height in pixels.
	 * @param int        $dest_w New width in pixels.
	 * @param int        $dest_h New height in pixels.
	 * @param bool|array $crop   Whether to crop image to specified width and height or resize.
	 *                           An array can specify positioning of the crop area. Default false.
	 */
	$output = apply_filters( 'image_resize_dimensions', null, $orig_w, $orig_h, $dest_w, $dest_h, $crop );
	if ( null !== $output )
		return $output;
	if ( $crop ) {
		// crop the largest possible portion of the original image that we can size to $dest_w x $dest_h
		$aspect_ratio = $orig_w / $orig_h;
		$new_w = min($dest_w, $orig_w);
		$new_h = min($dest_h, $orig_h);
		if ( ! $new_w ) {
			$new_w = (int) round( $new_h * $aspect_ratio );
		}
		if ( ! $new_h ) {
			$new_h = (int) round( $new_w / $aspect_ratio );
		}
		$size_ratio = max($new_w / $orig_w, $new_h / $orig_h);
		$crop_w = round($new_w / $size_ratio);
		$crop_h = round($new_h / $size_ratio);
		if ( ! is_array( $crop ) || count( $crop ) !== 2 ) {
			$crop = array( 'center', 'center' );
		}
		list( $x, $y ) = $crop;
		if ( 'left' === $x ) {
			$s_x = 0;
		} elseif ( 'right' === $x ) {
			$s_x = $orig_w - $crop_w;
		} else {
			$s_x = floor( ( $orig_w - $crop_w ) / 2 );
		}
		if ( 'top' === $y ) {
			$s_y = 0;
		} elseif ( 'bottom' === $y ) {
			$s_y = $orig_h - $crop_h;
		} else {
			$s_y = floor( ( $orig_h - $crop_h ) / 2 );
		}
	} else {
		// don't crop, just resize using $dest_w x $dest_h as a maximum bounding box
		$crop_w = $orig_w;
		$crop_h = $orig_h;
		$s_x = 0;
		$s_y = 0;
		list( $new_w, $new_h ) = wp_constrain_dimensions( $orig_w, $orig_h, $dest_w, $dest_h );
	}
	// if the resulting image would be the same size or larger we don't want to resize it
	if ( $new_w >= $orig_w && $new_h >= $orig_h && $dest_w != $orig_w && $dest_h != $orig_h ) {
		return false;
	}
	// the return array matches the parameters to imagecopyresampled()
	// int dst_x, int dst_y, int src_x, int src_y, int dst_w, int dst_h, int src_w, int src_h
	return array( 0, 0, (int) $s_x, (int) $s_y, (int) $new_w, (int) $new_h, (int) $crop_w, (int) $crop_h );
}
...
?>

其他

英文文档：https://developer.wordpress.org/reference/functions/image_resize_dimensions/