(PHP 4, PHP 5)
imagegammacorrect — 对 GD 图像应用 gamma 修正
$image
, float $inputgamma
, float $outputgamma
)
imagegammacorrect() 函数用给定的输入 gamma 值
inputgamma 和输出 gamma 值
outputgamma 对一幅 GD
图像流（image）应用 gamma 修正。
brian dot duncan at fife dot co dot uk (2002-01-26 05:46:26)
Just thought I'd add how I used the gamma correction function (seeing as no-one had done so previously). works great.
I used a form which has a parameter $GAMMA, so I usually type in something like 1.6
$image = ImageCreateFromJpeg ( "pictures/".$PICTURE2 ) ;
if ($GAMMA != "")
{
$GammaFloat = (double) $GAMMA ;
imagegammacorrect ($image, 1.0, $GammaFloat ) ;
// now save the file
imagejpeg ( $image, "pictures/"."$PICTURE2", 90 ) ;
}