Newbie Q: Colours

["George Ogata" <g_ogata ihug com au>]

Hi,

I'm trying to work out how to do coloured drawing stuff.  I've read the FAQ,
the tute, the reference, archives, other sources, and this colour
kerfuffle's giving me the shiz.

As a "trivial" exercise, I'm simply trying to open up a GtkWindow and smack
a dirty big blue rectangle in it.  It won't work:

#include <gtk/gtk.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
  GtkWidget *darea1, *mainWindow;
  GdkGC *gc;
  GdkColor *blue;

  // init
  gtk_init(&argc, &argv);

  // main window
  mainWindow = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_widget_show(mainWindow);

  // drawing area
  darea1 = gtk_drawing_area_new();
  gtk_container_add(GTK_CONTAINER(mainWindow), darea1);
  gtk_widget_realize(darea1);

  // make color
  blue = malloc(sizeof(GdkColor));
  blue->pixel = 255;
  blue->red = 0;
  blue->green = 0;
  blue->blue = 65535;
  gdk_colormap_alloc_color(gdk_colormap_get_system(), blue, TRUE, TRUE);

  // make gc and set fgcolor
  gc = gdk_gc_new(darea1->window);
  gdk_gc_set_foreground(gc, blue);

  // make it happen
  gdk_draw_rectangle (darea1->window,
        gc,
        TRUE,
        0, 0,
        darea1->allocation.width,
        darea1->allocation.height);

  gtk_widget_show(darea1);

  gtk_main();
  return 0;
}

Can someone please tell me what's wrong?

Also, is there any point in explicitly setting the `pixel' field of a
GdkColor?  FAQ 7.2 does it, but I thought it was the allocating function's
job.

TIA.