Re: [gtkmm] How to modify Gdk::Pixbuf data

[Ole Laursen <olau hardworking dk>]

Silviu D Minut <minutsil cse msu edu> writes:

> I need to read an image from the disk, display it, do some image
> processing on it (filtering, edge detection, etc.) and then display again
> the results.
> 
> So I use a Gdk::Pixbuf for that, which is a protected member in some
> class. First I do
> 
> Glib::RefPtr<Gdk::Pixbuf> pixbuf_ = creat_from_file("imagefile");
> 
> Then I get the data from the pixbuf_
> 
> u_char * pixbufdata_=pixbuf_->get_data();
> 
> and I copy it to a buffer (u_char * data) in memory, in a for loop.

Don't do that. Work directly on the pixbuf data, then call simply call
image->set_pixbuf(pixbuf) (or whatever) when you are done.

For working with the data, you may want to have a look at my pixbuf
iterators:

  http://www.cs.auc.dk/~olau/misc/pixbuf-drawing.hpp

I've used them extensively myself. I wrote a mail about the concept
here:

  http://mail.gnome.org/archives/gtkmm-list/2003-January/msg00198.html


Perhaps it is time to revise them for inclusion in gtkmm? My time is
limited right now, though.

-- 
Ole Laursen
http://www.cs.auc.dk/~olau/