wp_image_matches_ratio( int $source_width, int $source_height, int $target_width, int $target_height )
Helper function to test if aspect ratios for two images match.
Parameters
 $source_width

(Required) Width of the first image in pixels.
 $source_height

(Required) Height of the first image in pixels.
 $target_width

(Required) Width of the second image in pixels.
 $target_height

(Required) Height of the second image in pixels.
Return
(bool) True if aspect ratios match within 1px. False if not.
Source
File: wpincludes/media.php
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 = ( abs( $constrained_size[0]  $expected_size[0] ) <= 1 && abs( $constrained_size[1]  $expected_size[1] ) <= 1 );
return $matched;
}
Changelog
Version  Description 

WP4.6.0  Introduced. 