Image

Adjust

adjust() changes brightness, contrast, saturation, and gamma in one pass.

Example

Source Adjusted
Landscape source Adjusted image 
<?php

use Alto\Image\Image;

Image::open('source-landscape.png')
    ->adjust(brightness: -15, contrast: 30, saturation: -40, gamma: 1.1)
    ->save('adjust.png');

Options

Option Default Range
brightness 0 -100 to 100
contrast 0 -100 to 100
saturation 0 -100 to 100
gamma 1.0 0.1 to 10.0

Edge cases

  • Saturation -100 removes colour.
  • Extreme values can clip shadows or highlights.
  • Dimensions and alpha do not change.

Driver support

Imagick is exact. GD approximates the requested controls.