Re: [Boost-users] BGL: write_graphviz and bundled properties

19 Apr 2006

      On Wednesday 19 Apr 2006 16:46, Johan Oudinet wrote:
...
On 4/19/06, Fred Labrosse  wrote:
...
All,
First, I'm very new to boost and BGL, so please forgive me if this is
trivial.
I've created a graph (adjacency_list) using bundled properties and am now
trying to write it as a dot file.  I've written my property writer, but
when I compile, I get several of:
/usr/include/boost/graph/graphviz.hpp: In function `void
[snip]
Not being very good at deciphering all that, I'm not sure what is
happening. I do understand that it's missing an extraction operator but
I'm not sure on what.  The actual line in graphviz.hpp is:
out << get(vertex_id, *i);
Two questions:
- Could somebody tell me exactly what that get returns?
get returns the value from vertex_descriptor *i in the property map
vertex_id
In your code, your adjacency_list uses listS so this vertex_id
property is not define! That's the problem.
When you call write_graphviz, specify a property map to get an index
from a vertex_descriptor (follow the example with write_graphviz and
dynamic properties)
Many thanks for replying.  However, I'm not sure how to do that.  Here are the 
relevant bits of my code (sorry for the length):

class place
{
public:
   place(const imalib::imageD3* anAppearance, const std::string& aName,
         unsigned short aNumber)
      : appearance(anAppearance),
      name(aName),
      number(aNumber)
   {
   }
   ~place();
   const imalib::imageD3* getAppearance() const
   {
      return(appearance);
   }
   const std::string& getName() const
   {
      return(name);
   }
   unsigned short getNumber() const
   {
      return(number);
   }
private:
   const imalib::imageD3* appearance;
   std::string name;
   unsigned short number;
};

class placeWriter
{
public:
   placeWriter(const mapType& g)
      : g(g)
   {}
   void operator()(std::ostream& out,
                   const mapType::vertex_descriptor& v) const
   {
      static imalib::imageRGB anImage;

      out << "[label=\"" << g[v].getNumber() << "\",shapefile=\""
         << g[v].getName() << "\"];\n";

      g[v].getAppearance()->toRGB(&anImage);
      anImage.write(g[v].getName());
   }
private:
   const mapType& g;
};

typedef boost::adjacency_list mapType;

mapType theMap;

std::ofstream of(filename.c_str());
placeWriter pw(theMap);
write_graphviz(of, theMap, pw);

Should that be something like:

default_writer dw;
default_writer gw;
write_graphviz(of, theMap, pw, dw, gw, get(&place.getNumber(), theMap));

???
This was actually taken from an example on bundled properties.

Cheers,

Fred