So your mean is all the drawing action must be done through the
"expose-event", isn't it ?
And what is the "Cairo API"? Is it the GTK+'s official api in the
<gtk/gtk.h>?
Thank again, I'm the beginner of the GTK+.
On Tue, Aug 12, 2008 at 6:48 PM, Emmanuele Bassi <[EMAIL PROTECTED]> wrote:
> On Tue, 2008-08-12 at 18:24 +0800, Wu Yin wrote:
> > Thanks very much. But I have Another question:
> > I want to draw line on my own initiative, don't use "expose-event" and
> callback function.
>
> why not? that's how you do what you want to do.
>
> > Like the following code, but the code can't do what I want.
>
> because it's not how you do what you want to do.
>
> > Please tell me how to do this?
> >
> >
> > Code:
> >
> +-------------------------------------------------------------------------------------
> > | int main(int argc, char *argv[])
> > | {
> > | GtkWidget *w;
> > |
> > | gtk_init(&argc, &argv);
> > |
> > | w = gtk_window_new(GTK_WINDOW_TOPLEVEL);
> > | g_signal_connect(GTK_OBJECT(w), "destroy",
> G_CALLBACK(gtk_main_quit), NULL);
>
> don't cast to GTK_OBJECT: it's a useless type check, and
> g_signal_connect() takes a gpointer as the first argument.
>
> > | gtk_widget_realize(w);
> > | gdk_draw_line(w->window,
> w->style->fg_gc[GTK_WIDGET_STATE(w)],
> > | 0, 0, 120, 120);
>
> don't use gdk_draw_* API: it's long deprecated (gtk+ 2.8 deprecated that
> family of functions).
>
> connect to the ::expose-event signal, get the cairo context from the
> GdkWindow and use the Cairo API to draw:
>
> static gboolean
> my_expose_event (GtkWidget *widget, GdkEvent *event, gpointer data)
> {
> cairo_t *cr = gdk_cairo_create (GDK_DRAWABLE (widget->window));
> GdkColor color;
>
> color = w->style->fg[GTK_WIDGET_STATE (widget)]
>
> cairo_move_to (cr, 0, 0);
> cairo_line_to (cr, 120, 120);
> gdk_cairo_set_source_color (cr, &color);
>
> cairo_stroke (cr);
>
> cairo_destroy (cr);
>
> return FALSE;
> }
>
> [WARNING: untested code, written from memory - use the Cairo API
> reference to check the functions]
>
> ciao,
> Emmanuele.
>
> --
> Emmanuele Bassi,
> W: http://www.emmanuelebassi.net
> B: http://log.emmanuelebassi.net
>
> _______________________________________________
> gtk-list mailing list
> [email protected]
> http://mail.gnome.org/mailman/listinfo/gtk-list
>
_______________________________________________
gtk-list mailing list
[email protected]
http://mail.gnome.org/mailman/listinfo/gtk-list
