Re: [boost] [GTL] - geometric template library - determininginterest

From: Suto, Gyuszi (gyuszi.suto_at_[hidden])
Date: 2007-10-10 18:24:03

Fernando Cacciola wrote:
> Can you show us in as much detail as possible how do you do that with
> a very concrete example?
> 
> Say I have:
> 
> struct MyPoint { x,y} ;
> 
> MyPoint p ;
> 
> and I want to call
> 
> GTL::foo(p);
> 
> with the BGL-style of adaptation I write exactly that line (this is
> what 
> Joel means when he says that you can pass user types AS-IS).
> 
> What would I need to do in GTL?
> 
> And, MORE importantly, what does GTL do, exactly, to adapt my "p"
> objet there?
> 

You would do write an interface specialization for MyPoint
My syntax is not exact, just writing from memory:

#include <Gtl.h>
template <>
class gtl::PointInterface<MyPoint> {
  pointSet() { ... };
  pointGet() {....};
  pointConstruct() { ... };
};

then you would typedef:
typedef gtl::PointImpl<MyPoint> Point;
// and from here on you're set to use the full GTL on MyPoint

Point p1(..), p2(..), p3(..);
p1 == p2;
double d = p1.euclidieanDistance(p2.transform(t) - p3);
(p1 += (p2 - p3).set(HORIZONTAL, p2.get(HORIZONTAL) +
p3.get(VERTICAL))).toward(p3);
etc.

Gyuszi