Posted by Marcin on 08/04/07 18:21

Hi all,

I am trying to merge two images with multiplying their values (just like
multiplying layers in any image processing tool, e.g. Photoshop) - using
GD library.

All I found is function imagelayereffect(), but option
IMG_EFFECT_MULTIPLY is apparently not implemented... My code looks like
this:

imagelayereffect($mapImage, IMG_EFFECT_MULTIPLY);
imagecopymerge($mapImage, $clickImage, 10, 10, 0, 0, $owidth, $oheight,
100);

and it of course does not work.

Do you have any idea, how to achieve the same as below Imagick code with
GD library??

$mapImage->compositeImage($clickImage, Imagick::COMPOSITE_BUMPMAP,
$x-$halfWidth, $y-$halfWidth);

OR how to optimize color change (color lookup table) with Imagick -
below code takes very long time and works much better with GD... :

$run = 'convert full.png -type TruecolorMatte colors.png -fx
"v.p{0,u*v.h}" final.png';
system($run);

TIA, m.

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