Use c++ to draw a figure of a graph(data structure)
in [C++]
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From: weii meng on 12 Dec 2009 16:38 { Algorithm questions still belong to a language-independent forum, but questions about using the Boost Graph Library can fit here. -mod } Hi,all. I need to draw a figure of a graph(data structure). C++ is used in my code. The moderators told me to go to a language-independent forum. Considering *boost graphic library* may help,I think here is the best place. I can't get the whole graph all at once. Eachtime I get a pair of points,they indicate an edge and two vertexes of the graph. It's easy to store the graph. But I don't know how to get a rational layout of the graph,so that the figure looks symmetrical and balanced. Another difficult problem(to me) is how to reduce cross-lines. Any suggestion will be highly appreciated. Thanks in advance! -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: Joe Smith on 13 Dec 2009 08:15 "weii meng" <willgun.x(a)gmail.com> wrote in message news:3317a2e2-7a34-42c0-a088-49f0194bd6e0(a)r24g2000prf.googlegroups.com... >{ Algorithm questions still belong to a language-independent forum, > but questions about using the Boost Graph Library can fit here. -mod } > > > Hi,all. > > I need to draw a figure of a graph(data structure). C++ is used in my > code. > The moderators told me to go to a language-independent forum. > Considering *boost graphic library* may help,I think here is the best > place. If you want to learn about how to use the Boost Graph Library, for your problem, this group is definately more appropriate than a language independant one, but less appropriate than a boost mailing list. The BGL is rather complicated. If you want somebdoy to help you through an example, of creating a graph using it, we would need to know if the graph is director or not. If vertices are identifed by a name or a number. If at the start you know the number of vertices, or not. Etc. Unfortunately for you, the implemented Graph layout algorithms may not be what you want. They focus on placement of the vertices and symmetry, but pay no attention to the number of times edges will cross. Minimizing that is desireable, but is difficult, and few algorithms attempt it. Depending on the structure of the graph, this might be acceptable, as for some structures the implemented algorithms will tend to have few overlaps. For others though things are not as nice. As for finding other algorithms, the only one I have found that might be suitable for your purpose is the algorithm used by Graphviz's dot. This algorithm however is only good for directed graphs where it is desired that edges tend to all face the same general direction. (I.e. edges or normally from higher in the image to lower in the image, or from left to right). -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: Andrew on 14 Dec 2009 00:44 On 13 Dec, 09:38, weii meng <willgu...(a)gmail.com> wrote: > { Algorithm questions still belong to a language-independent forum, > but questions about using the Boost Graph Library can fit here. -mod } > > Hi,all. > > I need to draw a figure of a graph(data structure). C++ is used in my > code. > The moderators told me to go to a language-independent forum. > Considering *boost graphic library* may help,I think here is the best > place. > > I can't get the whole graph all at once. Eachtime I get a pair of > points,they indicate an edge and two > vertexes of the graph. > > It's easy to store the graph. But I don't know how to get a rational > layout of the graph,so that the figure looks symmetrical and > balanced. Well, this is the main problem. The boost graph library, like other graph libraries, concentrates on the representation of the graph, rather than how to draw it. Drawing involves graphics and there is no std way to do graphics in C++ (yet). There are loads of libraries and loads of approaches, but nothing std. My approach would be to write an output file suitable as input to a graph drawing program. Dot (aka graphviz) is quite popular. However, dot does have a habit of drawing non-trivial graphs with many crossing lines. A more sophisticated graph drawing program is uDraw (http:// www.informatik.uni-bremen.de/uDrawGraph/en/index.html), formerly known as Da Vinci. This does a much better job but has a more complicated file format. Regards, Andrew Marlow -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
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