Using WordPress ‘get_udims()’ PHP function

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The get_udims() WordPress PHP function calculates the new dimensions for a downsampled image.

Usage

$new_dimensions = get_udims( $current_width, $current_height );

Parameters

  • $width (int) – Required. Current width of the image.
  • $height (int) – Required. Current height of the image.

More information

See WordPress Developer Resources: get_udims()

Examples

Reducing Image Size by Half

This example calculates the dimensions for an image that needs to be reduced by 50%.

$current_width = 800;
$current_height = 600;
$scale_factor = 0.5;

$new_width = $current_width * $scale_factor;
$new_height = $current_height * $scale_factor;

$new_dimensions = get_udims( $new_width, $new_height );

Maintaining Aspect Ratio

This example maintains the aspect ratio while resizing an image to a maximum width of 400px.

$current_width = 800;
$current_height = 600;
$max_width = 400;

$scale_factor = $max_width / $current_width;

$new_width = $current_width * $scale_factor;
$new_height = $current_height * $scale_factor;

$new_dimensions = get_udims( $new_width, $new_height );

Resizing Image Based on Height

This example resizes an image based on a maximum height of 300px, maintaining its aspect ratio.

$current_width = 800;
$current_height = 600;
$max_height = 300;

$scale_factor = $max_height / $current_height;

$new_width = $current_width * $scale_factor;
$new_height = $current_height * $scale_factor;

$new_dimensions = get_udims( $new_width, $new_height );

Resizing Image Based on Smallest Dimension

This example resizes an image based on the smallest dimension, in this case, the height, with a target of 200px.

$current_width = 800;
$current_height = 600;
$target_dimension = 200;

$scale_factor = min( $current_width, $current_height ) / $target_dimension;

$new_width = $current_width * $scale_factor;
$new_height = $current_height * $scale_factor;

$new_dimensions = get_udims( $new_width, $new_height );

Resizing Image Based on Largest Dimension

This example resizes an image based on the largest dimension, in this case, the width, with a target of 600px.

$current_width = 800;
$current_height = 600;
$target_dimension = 600;

$scale_factor = max( $current_width, $current_height ) / $target_dimension;

$new_width = $current_width * $scale_factor;
$new_height = $current_height * $scale_factor;

$new_dimensions = get_udims( $new_width, $new_height );