W3C home > Mailing lists > Public > www-svg@w3.org > September 1999


From: Hundiak, Arthur <ahundiak@ingr.com>
Date: Wed, 29 Sep 1999 14:33:56 -0500
Message-ID: <0E06EC70934FD211B574080009EDC5280168B469@HQ9>
To: www-svg@w3.org, svg-comments@w3.org
About 2 years ago my company wrote a translator to convert 2d geometry to a
steel cutting system.  We send an external contour for a piece a steel,
internal contours for holes, marking lines to indicate how pieces fit
together and some text to keep track of stuff.  XML was just getting going
back then so we implemented the intermediate data file in xml.  It's working
quite well.  We made up our own path object for doing the contours as well
as our own text object.

I'd like to take advantage of xml's namespace capabilities and swap out the
vector and text portions of our file format with the svg equivalent.  Here
are some of the problems that I have encountered.

1. The <path> object is fatally flawed by requiring all the vertex
information be contained in one "d=..." attribute.  I have read the emails
and the arguments about why it was done this way but the sad fact is that
you need some kind of object for the vertexes.  You can easily have a path
with several hundred (or thousand) vertexes.  You can't rely an attribute
being able to store all the information.  As it stands now, we would
probably have to use a nested path approach in which each vertex becomes
it's own path object.  Not the ideal approach. Bring back the <data> object.
Have it use the d attribute.

2.  A great many legacy cad oriented systems get along just fine with line
segments and circular arcs.  Please reconsider adding a circular arc to the
basic shapes as well as a circularArcTo for the path object.  Arcs defined
by three points are easy to generate and easy to decode.  It would make life
so much easier for people who don't care about bezier curves. At the very
least, put something in the spec recomending the best way to deal with
circular arcs.

3. Adding a "point" to the basic shapes would also be nice.  Reference
points are quite common. 

4. There seems to be quite a bit of debate concerning the wisdom of putting
multiple lists of attributes into one attribute value.  style="fill:none;
stroke:black; stroke-width:100" is an example.  Maybe there is some strange
reason why this makes sense but please do us old timers a favor and give us
the option of doing things like style_fill="none" style_stroke="black".  I
really don't see the point of having to write a parser inside of a parser.

5. I'd like to see a layer="xxx" attribute to specify a drawing layer.
Almost all cad systems support the notion of layers so this would help when
moving files from one system to another.

Art Hundiak
Received on Wednesday, 29 September 1999 15:34:08 UTC

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