Re: How to grayscale a gif using bit-swapping

On 21 Mar, 18:27, Lars Erik Bryld <larse...@xxxxxxxxxxxxxxx> wrote:

I am trying to convert a (supposedly) working python script into php.
The script reads a colour gif-picture and produces a greyscale copy of
it.

<snip>

It would be safer to use GD. There's even an example of how to do this
at http://www.php.net/manual/en/function.imagecolorset.php

(FWIW, both the example above and your own code use an averaging
method to determine the grey scale; while color models vary, it might
be more approriate to measure the size of the orthognal vectors -
(integer)(sqrt($red*$red + $green*$green + $blue*$blue)*0.5769)
)

C.

.