#include <gtk/gtk.h>

static gboolean
expose(GtkWidget *area, GdkEventExpose *expose, GtkWidget *label)
{
	gchar *s;
	double x1,y1, x2,y2;
	cairo_t	*cr;

	cr = gdk_cairo_create(area->window);

	cairo_arc(cr, 250.0, 250.0, 157.0, 5.147, 3.432);
	cairo_set_line_width(cr, 154.0);

	cairo_stroke_extents(cr, &x1,&y1, &x2,&y2);

	s = g_strdup_printf("arc stroke extents:\n%.2fx%.2f %.2fx%.2f\n", x1,y1, x2,y2);
	gtk_label_set_text(GTK_LABEL(label), s);
	g_free(s);

	cairo_set_source_rgba(cr, 0.0,0.0,1.0,0.7);
	cairo_stroke(cr);

	cairo_rectangle(cr, x1,y1,x2-x1,y2-y1);
	cairo_set_source_rgba(cr, 1.0,0.0,0.0,0.5);
	cairo_fill(cr);

	cairo_destroy(cr);

	return TRUE;
}

int
main(int argc, char **argv)
{
	GtkWidget *window;
	GtkWidget *vbox;
	GtkWidget *area;
	GtkWidget *label;

	gtk_init(&argc, &argv);

	window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
	gtk_widget_set_size_request(window, 550,550);
	g_signal_connect(window, "delete-event", G_CALLBACK(gtk_main_quit), 0);

	vbox = gtk_vbox_new(FALSE, 6);
	gtk_container_add(GTK_CONTAINER(window), vbox);

	area = gtk_drawing_area_new();
	gtk_box_pack_start(GTK_BOX(vbox), area, TRUE,TRUE, 0);

	label = gtk_label_new("");
	gtk_label_set_selectable(GTK_LABEL(label), TRUE);
	gtk_box_pack_start(GTK_BOX(vbox), label, FALSE,FALSE, 2);

	g_signal_connect(area, "expose-event", G_CALLBACK(expose), label);

	gtk_widget_show_all(window);

	gtk_main();

	return 0;
}