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
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