Version 5.0 The LEDA User Manual

eturn 0;
}
template
void GW.set update(geo scene res, geowin update& up)
makes up the update object of res. Precondition: res
points to a scene of type GeoResultScene .
template
void GW.set update(geo scene res, void (∗f update)(const S& , R& ))
makes f update the update function of res.
Precondition: res points to a scene of type
GeoResultScene .
template
GeoResultScene∗ GW.new scene(geowin update& up, geowin redraw& rd,
geo scene sc input, string str,
D3 FCN f = NULL)
creates a new result scene with name str. The input
scene for this new result scene will be sc input. The
update object will be ub. The redraw object will be
rd.
The third variant of the example program uses an update and redraw object. We provide
a user defined class for update and redraw of the result scene.
#include
#include
using namespace leda;
class hull_update_redraw : public geowin_update ,
public geowin_redraw
{
list polys;
public:
void update(const list& L, list& P)
{
polys.clear();
polys.append(CONVEX_HULL_POLY(L));
}
void draw(window& W,color c1,color c2,double x1,double y1,double x2,double y2)
{
polygon piter;
segment seg;
forall(piter, polys){
forall_segments(seg, piter){
W.draw_arrow(seg, c1);
}
}