Version 5.0 The LEDA User Manual

geowin new scene and geowin get objects with GW as an additional first parameter.
All new scene operations can get as an optional last parameter a pointer to a function
that is used to compute the three-dimensional output of the scene. The type of such a
function pointer f is
void (∗f)(const T &, d3 window&, GRAPH &))
where T is the type of the container used in the scene (for instance list). The
function gets a reference to the container of it’s scene, a reference to the output d3 window
and to the parametrized graph describing the three-dimensional output. The function
usually adds new nodes and edges to this graph. Note that every edge in the graph must
have a reversal edge ( and the reversal information has to be set).
Example:
void segments_d3(const list& L,d3_window& W,
GRAPH& H)
{
GRAPH G;
segment iter;
forall(iter,L) {
node v1 = G.new_node(d3_point(iter.source().xcoord(),
iter.source().ycoord(),0));
node v2 = G.new_node(d3_point(iter.target().xcoord(),
iter.target().ycoord(),0));
edge e1 = G.new_edge(v1,v2);
edge e2 = G.new_edge(v2,v1);
G.set_reversal(e1,e2);
}
H.join(G);
}
In this simple example the function gets a list of segments. For every segment in the list
two new nodes and two new edges are created. The reversal information is set for the two
edges. At the end the local graph G is merged into H.
The following templated new scene operation can be used to create edit scenes. The
CONTAINER has to be a list , where T is one of the following 2d LEDA kernel type
• (rat )point
• (rat )segment
• (rat )line
• (rat )circle
• (rat )polygon