On 03 Feb 2003, Lars Clausen wrote:
On Mon, 3 Feb 2003, John Edstrom wrote:
On Mon, Feb 03, 2003 at 09:39:58AM -0600, Lars Clausen wrote:
On Sun, 2 Feb 2003, John Edstrom wrote:
So far my biggest concern with a dot2dia transformation is that dot
uses splines and dia doesn't.  Some of dot's edges get pretty baroque
in complex graphs and arcs and polylines can't do equivalently
tortuous paths as well.

Can't you use Dia's beziers?  As I understand it, there are standard
translations between most such things.

My background is not in graphics and I didn't know that.  That would
simplify things immensely.  Is there a list of such algorithms

Note also that Dia's "bezier" isn't really a Bezier line.  It's a string
of line segments (I believe Bezier) with 4 control points each.  The xfig
import plugin has some hacky translation from FIG style splines to Dia
beziers, but it's not exact.

Some more update on this:  While Dia's lines are indeed fragments of cubic
beziers, it's not trivial to translate from B-splines or Calmutt-Rom
splines.  Boehm has a paper that describes the appropriate insertion of
knots to do a full translation, but it's beyond my current time limits.
I'll let the xfig import just use the rough hack I did earlier.

It appears that dot splines are actually beziers, which should make the
conversion easier.  I haven't found any more info other than the fact that
they're called beziers internally.


Lars Clausen (| Hårdgrim of Numenor
"I do not agree with a word that you say, but I   |----------------------------
will defend to the death your right to say it."   | Where are we going, and
    --Evelyn Beatrice Hall paraphrasing Voltaire  | what's with the handbasket?

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