(PECL imagick 2, PECL imagick 3)
Imagick::gammaImage — Gamma-corrects an image
public Imagick::gammaImage ( float $gamma [, int $channel = Imagick::CHANNEL_DEFAULT ] ) : bool
Gamma-corrects an image. The same image viewed on different devices will have perceptual differences in the way the image's intensities are represented on the screen. Specify individual gamma levels for the red, green, and blue channels, or adjust all three with the gamma parameter. Values typically range from 0.8 to 2.3.
gamma
The amount of gamma-correction.
channel
Provide any channel constant that is valid for your channel mode. To apply to more than one channel, combine channeltype constants using bitwise operators. Refer to this list of channel constants.
Returns true on success.
Throws ImagickException on error.
Example #1 Imagick::gammaImage()
<?php
function gammaImage($imagePath, $gamma, $channel) {
$imagick = new \Imagick(realpath($imagePath));
$imagick->gammaImage($gamma, $channel);
header("Content-Type: image/jpg");
echo $imagick->getImageBlob();
}
?>
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https://www.php.net/manual/en/imagick.gammaimage.php