Re: Matrix of pixels from/to an image file

[José Romildo Malaquias <romildo uber com br>]

On Sun, Mar 24, 2002 at 09:01:58AM -0500, Havoc Pennington wrote:
> 
> José Romildo Malaquias <romildo uber com br> writes:
> > 
> > Please, point me to an easy way of obtaining the matrix of pixels
> > from an image file (in any common format, like jpeg, png or xpm)
> > and the reverse, given the matrix of pixels, write it as an
> > image file.
> > 
> > I am programming in C/C++ for Linux with Gtk+.
> > 
> 
> Most people would use the gdk-pixbuf library, which comes separately
> for GTK 1.2 and is included in GTK 2.0.

Yes, gdk-pixbuf can solve the problem. But I am looking for something
simple. I just need to have the matrix of pixels from my (grayscale)
image, which is saved in a common file format. Once I have the pixels
of the image, I want to manipulate them somehow (like applying some
digital filters for image enhancement) and get a new matrix of pixels
(the processed image). For rendering the image from its matrix of
pixels I am already using the plain Gtk+ drawing area widget toghether
with its expose event. Also I want to save the pocessed image in
a common file format.

After some searching, I have found that the PPM image file format
is extremely simple and understood by lots of image viewers. So I
have written two C functions to read/write an image from/to a PPM
file with easy.

Regards.
-- 
Prof. José Romildo Malaquias               Departamento de Computação
http://iceb.ufop.br/~romildo       Universidade Federal de Ouro Preto
romildo iceb ufop br                                           Brasil
romildo uber com br