GTK+ Forums

sawerset · Joined: 16 Jul 2008 Posts: 1

I need to do such thing to draw some rectangles and circles as a background and to place above them buttons, labels.
Is it posible?
How it can be done?

dreblen · Posted: Sun Jul 20, 2008 1:19 am Post subject:

you can hack the expose event of your widget to insert drawing code,
something like this (note that this doesn't work very well, but it's just an eample):

Code: (C)

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#include <gtk/gtk.h>
#include <math.h>

gboolean button_expose(GtkWidget *wi, GdkEventExpose *ev, gpointer user_data)
{
cairo_t *cr;
GtkAllocation alloc;

alloc = wi->allocation;

cr = gdk_cairo_create(wi->window);
cairo_arc(cr, alloc.width/2, alloc.height/2, MIN(alloc.width/3, alloc.height/3), 0, M_PI*2);
cairo_stroke(cr);

return FALSE; /* continue the event */
}

int main(int argc, char **argv)
{
GtkWidget *win;
GtkWidget *button;

gtk_init(&argc, &argv);

win = gtk_window_new(GTK_WINDOW_TOPLEVEL);
g_signal_connect(G_OBJECT(win), "delete_event", G_CALLBACK(gtk_main_quit), NULL);
gtk_container_set_border_width(GTK_CONTAINER(win), 10);

button = gtk_button_new();
g_signal_connect_after(G_OBJECT(button), "expose_event", G_CALLBACK(button_expose), NULL);
gtk_container_add(GTK_CONTAINER(win), button);
gtk_widget_show(button);

gtk_widget_show(win);

gtk_main();

return 0;
}