#7 How to decode a gif file with PDF417_dec.c?

[pacific]

Hi,
I'm using pdf417_enc.4.4.
I would like to decode a gif file with PDF417_dec.c.
I have created a function to read a gif file into the pixel_array.
The test gif file (attached) is 248x99 pixels.
"AIM USA 634 Alpha DRIVE Pittsburgh, PA 1"

I need help with the do_prelim() function
especially with
x_div_factor=40 and
y_div_factor=40.
Can this function be modified for an input gif file format?

Any help/suggestions would be appreciated.
Thanks
Dave

[pacific]

Test input gif file for PDF417_dec.c