WordPress Version: 5.3
/**
* Calculates the new dimensions for a down-sampled image.
*
* If either width or height are empty, no constraint is applied on
* that dimension.
*
* @since 2.5.0
*
* @param int $current_width Current width of the image.
* @param int $current_height Current height of the image.
* @param int $max_width Optional. Max width in pixels to constrain to. Default 0.
* @param int $max_height Optional. Max height in pixels to constrain to. Default 0.
* @return array First item is the width, the second item is the height.
*/
function wp_constrain_dimensions($current_width, $current_height, $max_width = 0, $max_height = 0)
{
if (!$max_width && !$max_height) {
return array($current_width, $current_height);
}
$width_ratio = 1.0;
$height_ratio = 1.0;
$did_width = false;
$did_height = false;
if ($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);
}