Re: filling a drawing area with a pattern

[Sander Marechal <s marechal jejik com>]

Hey Nickolay,

Thanks for your response. Your example, along with an article I managed 
to dig up after half a day of googling, helps me a great deal to 
understand the connection between widgets and pixmaps. This just shows 
that a good example is far better than frantically browsing the API 
specs, trying to make sense of it all :-)

Thanks!

--
Sander

PS: Your response didn't show at the list. I guess it only accepts mails 
 directed to it, not just cc'ed.


Nickolay V. Shmyrev wrote:
> В Втр, 14/03/2006 в 08:09 +0100, Sander Marechal пишет:
>
> > Hello,
> >
> > I'm pretty new to gnome development and I have trouble understanding how 
> > to draw your own things. My eventual objective is to make a hearts game, 
> > but that's a long way off. At the moment I am having trouble to set a 
> > background in my UI, much like the green striped background in AisleRiot.
> >
> > I am using libglade for my UI. The main window (where the cards are 
> > going to be) is a GtkDrawingArea called "table". I load up an image and 
> > try to fill the drawing area with it, but it doesn't show it. I've tried 
> > looking ar AilseRiot and see how they do it, but I can't figure it out. 
> > Here's my code, with comments as to what each step is supposed to do.
> >
> > Any idea what I am doing wrong? Probably lots :-) Thanks in advance!
> >
> > int main (int argc, char *argv[])
> > {
> > 	GtkWidget *table_widget;
> > 	GdkGC *table;
> >
> > 	/* Start up glade and show the UI */
> > 	gnome_init (PACKAGE, VERSION, argc, argv);
> > 	glade_gnome_init ();
> > 	xml = glade_xml_new (PACKAGE_SOURCE_DIR"/hearts.glade", NULL, NULL);
> > 	glade_xml_signal_autoconnect (xml);
> > 	
> > 	/* Load the background pixmap. get_pixmap() uses 
> > gdk_pixbuf_new_from_file() to load the image and returns a GdkPixmap 
> > pointer. I got this from the AisleRiot code. background_pixmap is a 
> > global. It does return a valid image, not NULL. */
> > 	background_pixmap = get_pixmap(PACKAGE_SOURCE_DIR"/pixmaps/baize.png");
> > 	
> > 	/* From what I read, I need a GDK Graphics Context to draw in, so here 
> > I create one. I can verify that it does return a GdkGC, and not NULL */
> > 	table_widget = glade_xml_get_widget (xml, "table");
> > 	table = gdk_gc_new (table_widget->window);
> > 	
> > 	/* This should fill the GC with the background image, right? */
> > 	gdk_gc_set_tile (table, background_pixmap);
> > 	gdk_gc_set_fill (table, GDK_TILED);
> >
> > 	/* wait for events */
> > 	gtk_main ();
> >
> > 	/* bye bye */
> > 	return 0;
> > }
>
>
> Hi Sander
>
> There are multiple ways to archive your goal. If you just need to draw a
> background on GtkDrawingArea, you can use the property of all X server
> windows - they may have a background set from pixmap. See the example
> attached. 
>
> That is simple and fastest way to draw some background but I suspect in
> your game you'll need more advanced operations. Probably you need to
> look at some canvas library like GooCanvas or another analog, they allow
> much more intelligent work with drawing. 
>
>
>
>
> ------------------------------------------------------------------------
>
> #include <gtk/gtk.h>
>
> static const char * xpm_data[] = {
> "16 16 3 1",
> "       c None",
> ".      c #000000000000",
> "X      c #FFFFFFFFFFFF",
> "                ",
> "   ......       ",
> "   .XXX.X.      ",
> "   .XXX.XX.     ",
> "   .XXX.XXX.    ",
> "   .XXX.....    ",
> "   .XXXXXXX.    ",
> "   .XXXXXXX.    ",
> "   .XXXXXXX.    ",
> "   .XXXXXXX.    ",
> "   .XXXXXXX.    ",
> "   .XXXXXXX.    ",
> "   .XXXXXXX.    ",
> "   .........    ",
> "                ",
> "                "};
>
> void quit ()
> {
>   exit (0);
> }
>
> int main( int   argc, 
>           char *argv[] )
> {
>   GtkWidget *window;
>   GtkWidget *drawing_area;
>   GtkWidget *vbox;
>   GtkStyle *style;
>   GdkPixmap *pixmap;
>   GdkBitmap *mask;
>   GtkWidget *button;
>
>   gtk_init (&argc, &argv);
>
>   window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
>   vbox = gtk_vbox_new (FALSE, 0);
>   gtk_container_add (GTK_CONTAINER (window), vbox);
>   gtk_widget_show (vbox);
>
>   g_signal_connect (G_OBJECT (window), "destroy",
>                     G_CALLBACK (quit), NULL);
>
>   /* Create the drawing area */
>
>   drawing_area = gtk_drawing_area_new ();
>   gtk_widget_set_size_request (GTK_WIDGET (drawing_area), 200, 200);
>   gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);
>
>   /* And a button */
>   button = gtk_button_new_with_label ("Quit");
>   gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);
>   g_signal_connect_swapped (G_OBJECT (button), "clicked",
> 			    G_CALLBACK (gtk_widget_destroy),
> 			    G_OBJECT (window));
>   gtk_widget_show_all (window);
>
>   /* If shown, GtkWidget is associated with GdkWindow and GtkStyle */
>
>   style = gtk_widget_get_style (drawing_area);
>   pixmap = gdk_pixmap_create_from_xpm_d (drawing_area->window,  &mask,
>                                          &style->bg[GTK_STATE_NORMAL],
>                                          (gchar **)xpm_data);
>   
>   gdk_window_set_back_pixmap (drawing_area->window, pixmap, FALSE);
>
>
>   gtk_main ();
>
>   return 0;
> }