I followed your advice and found that "Cairo" is a vector graphics library. I think the vector drawing action will cost more cpu, gpu or ram then gdk_draw_* API. But my target device is an embeded system with ARM9 cpu, and have not gpu. So I think the gdk_draw_* API is better of me and my device. Am I right?
And I found that the Cairo library had not be integrated into the GTK+ 2.12. I have to compile and intstall it into my embeded filesystem manually. Am I right? On 8/12/08, Emmanuele Bassi <[EMAIL PROTECTED]> wrote: > > 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 <[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 > -- > 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 > -- ---------------------------------------------- ┏━━━━━━━━━━━━━━━━━━━━━━━━┓ ┃菩提本无树，明镜亦非台。本来无一物，何处惹尘埃。┃ ┗━━━━━━━━━━━━━━━━━━━━━━━━┛
_______________________________________________ gtk-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/gtk-list
