(PECL imagick 3 >= 3.3.0)
Imagick::autoLevelImage — Adjusts the levels of a particular image channel
$channel = Imagick::CHANNEL_DEFAULT): boolAdjusts the levels of a particular image channel by scaling the minimum and maximum values to the full quantum range.
channelWhich channel should the auto-levelling should be done on.
成功时返回 true。
示例 #1 Imagick::autoLevelImage()
<?php
function autoLevelImage($imagePath) {
$imagick = new \Imagick(realpath($imagePath));
$imagick->autoLevelImage();
header("Content-Type: image/jpg");
echo $imagick->getImageBlob();
}
?>