Re: [dynagraph2-devel] graph resolution

[Gordon W. <go...@wo...>]

Hi Erik -

> Thanks again for writing Dynagraph, Gordon.  I like incrface; every
> bug I've found so far turned out to be an oversight on my part.

I'm glad you're enjoying Dynagraph.  Stephen North designed the  
incrface language; as you can see, it's a variant of the dot language  
graphviz uses.  In fact I believe the languages can be unified in the  
future.

> Edge pos precision can be increased!  It's controlled by the graph's
> resolution.

Oh, for some reason before I thought you were talking about the  
floating-point precision.  There is always some confusion about what  
these attributes mean, and I will probably want to rename them to make  
them clearer in later versions.

Resolution controls the minimum increment used for x and y  
coordinates.  The floating point coordinates are divided by these  
values in order to produce integers which are used internally, and  
then resolution is multiplied back in on output.

Unfortunately, the resolution attribute has to do with bitmap  
resolution in graphviz, which results in some incompatibilities.   
Really this attribute should be called minimal-increment or something.

> Errors such as "(exception) Assertion: cx>=px; .\Check.cpp, 107" only
> crop up when the resolution value is set too high.

Yes, invalid input should generate useful errors rather than hitting  
assertions deep in the sanity-check code.

> I could use a few hints regarding compiling graphviz and dynagraph for
> windows, although the binary will probably suffice for win32.  The
> unices have been straightforward.

Oh, has http://www.dynagraph.org/building-dgwin.php slipped out of  
date?  Please post any problems you're having.  Really dynagraph  
should have its own build process on windows apart from Dynagraph for  
Windows; the reason I still build dynagraph as part of dgwin is the  
dependencies on graphviz, which are currently handled by injecting  
visual studio projects into the graphviz source directory.  This could  
probably be cleaner, but on the other hand, the graphviz dependencies  
will also go away in due time.

Thanks for the feedback,
Gordon