M. Sokolewicz wrote:
Ulrik Witschass wrote:
Hello List,
I browses the PHP Manual for some time now but didn't find exactly what I
was looking for.
I need to turn images uploaded by a user to b/w images to use them in
pdflib, the resulting PDF has to be black and white.
Now my question:
a) is this possible?
yes, it is.
if(a)
b) do I do this with PHP Image functions (maybe colorallicate and
stuff like
that) or is it possible to actually do that in PDFLib?
I don't think it's doable using PDFLib, but you could write an
implementation yourself. Here's one I just wipped up (so it might not
work correctly).
what'll ya know... seems I forgot a line (*ashamed*)
it should be
<?php
$im = imagecreatefromWHATEVER($path);
$size = getimagesize($path);
$width = $size[0];
$height = $size[1];
$greyScaled = imagecreate($width, $height);
$pallet = array();
for($y=0;$y<$height;$y++) {
for($x=0;$x<$width;$x++) {
$index = imagecolorat($im, $x, $y);
$rgba = imagecolorsforindex($im, $index);
$newC = (($rgba['red']+$rgba['green']+$rgba['blue'])/3)
if(!isset($pallet[$newC])) {
$color = imagecolorallocate($greyScaled, $newC, $newC, $newC);
$pallet[$newC] = $color; // notice this line? it was missing :)
} else {
$color = $pallet[$newC];
}
imagesetpixel($greyScaled, $x, $y, $color);
}
}
header('Content-type: image/png');
imagepng($greyScaled);
imagedestroy($im);
imagedestroy($greyScaled);
?>
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