计算下采样图像的新尺寸。
原型
wp_constrain_dimensions( int $current_width, int $current_height, int $max_width, int $max_height )
描述
如果宽度或高度为空,则不对该维度应用约束。
参数
$current_width
(int)
(Required)
图像的当前宽度。
$current_height
(int)
(Required)
图像的当前高度。
$max_width
(int)
(Optional)
最大宽度(以像素为单位)约束到。默认值为0。
$max_height
(int)
(Optional)
以像素为单位的最大高度。默认值为0。
返回值
(array)
第一项是宽度,第二项是高度。
源文件
路径:wp-includes/media.php
<?php
...
function wp_constrain_dimensions( $current_width, $current_height, $max_width = 0, $max_height = 0 ) {
if ( !$max_width && !$max_height )
return array( $current_width, $current_height );
$width_ratio = $height_ratio = 1.0;
$did_width = $did_height = false;
if ( $max_width > 0 && $current_width > 0 && $current_width > $max_width ) {
$width_ratio = $max_width / $current_width;
$did_width = true;
}
if ( $max_height > 0 && $current_height > 0 && $current_height > $max_height ) {
$height_ratio = $max_height / $current_height;
$did_height = true;
}
// Calculate the larger/smaller ratios
$smaller_ratio = min( $width_ratio, $height_ratio );
$larger_ratio = max( $width_ratio, $height_ratio );
if ( (int) round( $current_width * $larger_ratio ) > $max_width || (int) round( $current_height * $larger_ratio ) > $max_height ) {
// The larger ratio is too big. It would result in an overflow.
$ratio = $smaller_ratio;
} else {
// The larger ratio fits, and is likely to be a more "snug" fit.
$ratio = $larger_ratio;
}
// Very small dimensions may result in 0, 1 should be the minimum.
$w = max ( 1, (int) round( $current_width * $ratio ) );
$h = max ( 1, (int) round( $current_height * $ratio ) );
// Sometimes, due to rounding, we'll end up with a result like this: 465x700 in a 177x177 box is 117x176... a pixel short
// We also have issues with recursive calls resulting in an ever-changing result. Constraining to the result of a constraint should yield the original result.
// Thus we look for dimensions that are one pixel shy of the max value and bump them up
// Note: $did_width means it is possible $smaller_ratio == $width_ratio.
if ( $did_width && $w == $max_width - 1 ) {
$w = $max_width; // Round it up
}
// Note: $did_height means it is possible $smaller_ratio == $height_ratio.
if ( $did_height && $h == $max_height - 1 ) {
$h = $max_height; // Round it up
}
/**
* Filters dimensions to constrain down-sampled images to.
*
* @since 4.1.0
*
* @param array $dimensions The image width and height.
* @param int $current_width The current width of the image.
* @param int $current_height The current height of the image.
* @param int $max_width The maximum width permitted.
* @param int $max_height The maximum height permitted.
*/
return apply_filters( 'wp_constrain_dimensions', array( $w, $h ), $current_width, $current_height, $max_width, $max_height );
}
...
?>
其他
英文文档:https://developer.wordpress.org/reference/functions/wp_constrain_dimensions/