On Tue, 2008-08-12 at 22:24 +0800, Wu Yin wrote: > So your mean is all the drawing action must be done through the > "expose-event", isn't it ? yes. > And what is the "Cairo API"? Is it the GTK+'s official api in the > <gtk/gtk.h>? you should read: http://cairographics.org http://library.gnome.org/devel/gdk/unstable/gdk-Cairo-Interaction.html "Cairo is a graphics library that supports vector graphics and image compositing that can be used with GDK. Since 2.8, GTK+ does most of its drawing using Cairo." ciao, Emmanuele. > On Tue, Aug 12, 2008 at 6:48 PM, Emmanuele Bassi <ebassi@xxxxxxxxx> > 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 > gtk-list@xxxxxxxxx > http://mail.gnome.org/mailman/listinfo/gtk-list > > > > _______________________________________________ > gtk-list mailing list > gtk-list@xxxxxxxxx > http://mail.gnome.org/mailman/listinfo/gtk-list -- Emmanuele Bassi, W: http://www.emmanuelebassi.net B: http://log.emmanuelebassi.net _______________________________________________ gtk-list mailing list gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
