W3C home > Mailing lists > Public > www-svg@w3.org > November 2002

Marker differences - ASV vs Batik

From: Niklas Gustavsson <niklas@protocol7.com>
Date: Sun, 1 Dec 2002 03:05:06 +0100
To: www-svg@w3.org
Message-ID: <asbqsq$s1p$1@main.gmane.org>
Cc: svg-developers@yahoogroups.com

(cross-post: be warned)

Hi all

When doing some experiments with markers I found some differences between
Batik 1.5b4 and ASV3 and I'm unsure to which one is correct. Please help me
out since I can't really judge based on the spec and I need to know where to
send the bug report :-)

I used this file:
http://www.protocol7.com/svg.net/tests/marker-01.svg

This produces the following rendering in ASV:
http://www.protocol7.com/svg/markerBugs/asv3.png
(note that the circled arrow should not be there at all. This is clearly a
bug in ASV).

In Batik it looks like this:
http://www.protocol7.com/svg/markerBugs/batik1.5b4.png

As you can see, the rotation of some of the markers differs between the two
implementations. Which one is correct?

The spec has the following to say about rotations on mid-markers: "if there
is a path segment coming into the vertex and another path segment going out
of the vertex, the marker's positive x-axis should point toward the angle
bisector for the angle at the given vertex, where that angle has one side
consisting of tangent vector for the path segment going into the vertex and
the other side the tangent vector for the path segment going out of the
vertex (note: if the tangent vectors are the same, the angle bisector equals
the two tangent vectors)".
(http://www.w3.org/TR/SVG11/painting.html#MarkerAlgorithm)

This doesn't really help me but for someone more fluent in math it might :-)

/niklas
http://www.protocol7.com
Received on Saturday, 30 November 2002 21:10:11 GMT

This archive was generated by hypermail 2.3.1 : Friday, 8 March 2013 15:54:23 GMT