Convert a GTK python script to C
Question: The following script will take a screenshot on a Gnome desktop.

    
    
    import gtk.gdk
    
    w = gtk.gdk.get_default_root_window()
    sz = w.get_size()
    pb = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB,False, 8, sz[0], sz[1])
    pb = pb.get_from_drawable(w, w.get_colormap(), 0, 0, 0, 0, sz[0], sz[1])
    if (pb != None):
        pb.save("screenshot.png", "png")
        print "Screenshot saved to screenshot.png."
    else:
        print "Unable to get the screenshot."
    

Now, I've been trying to convert this to C and use it in one of the apps I am
writing but so far i've been unsuccessful. Is there any what to do this in C
(on Linux)?

Thanks! Jess.


Answer: I tested this and it does work, but there might be a simpler way to go from
GdkPixbuf to a png this was just the first one I found. (There's no
`gdk_pixbuf_save()`)

    
    
    #include <unistd.h>
    #include <stdio.h>
    #include <gdk/gdk.h>
    #include <cairo.h>
    
    int main(int argc, char **argv)
    {
        gdk_init(&argc, &argv);
    
        GdkWindow *w = gdk_get_default_root_window();
    
        gint width, height;
        gdk_drawable_get_size(GDK_DRAWABLE(w), &width, &height);
    
        GdkPixbuf *pb = gdk_pixbuf_get_from_drawable(NULL, 
                           GDK_DRAWABLE(w), 
                           NULL, 
                           0,0,0,0,width,height);
    
        if(pb != NULL) {
            cairo_surface_t *surf = cairo_image_surface_create(CAIRO_FORMAT_RGB24, 
                                                               width, height);
            cairo_t *cr = cairo_create(surf);
            gdk_cairo_set_source_pixbuf(cr, pb, 0, 0);
            cairo_paint(cr);
            cairo_surface_write_to_png(surf, "screenshot.png");
            g_print("Screenshot saved to screenshot.png.\n");
        } else {
            g_print("Unable to get the screenshot.\n");
        }
        return 0;
    }
    

you'd compile like this: (assuming you save it as screenshot.c)

    
    
    gcc -std=gnu99 `pkg-config --libs --cflags gdk-2.0` screenshot.c -o screenshot
    

Edit: the stuff to save the pixbuf could also look like: (note I didn't try
this out, but it's only one line...) Thanks to kaizer.se for pointing out my
fail at doc reading :P

    
    
    gdk_pixbuf_save(pb, "screenshot.png", "png", NULL, NULL);
    

