W3C home > Mailing lists > Public > www-svg@w3.org > August 2004

Re: marker clarifications

From: Craig Northway <craign@cisra.canon.com.au>
Date: Thu, 19 Aug 2004 09:56:06 +1000
Message-ID: <4123EC96.2090508@cisra.canon.com.au>
To: Tim Rowley <tor@cs.brown.edu>
Cc: www-svg@w3.org


My  interpretation is that the first one should render three marker-mid, 
marker-start and marker-end, so five markers.  This is from Appendix F.5 
of the SVG 1.1 specification:

Markers, directionality and zero-length path segments:

   * If markers are specified, then a marker is drawn on every
     applicable vertex, even if the given vertex is the end point of a
     zero-length path segment and even if "moveto" commands follow each

The second path should render a marker-start and a marker-end, so two 
markers. I would not consider there to be a vertex in the middle of the 
ellipitcal arc.  I think this is a result of subdividing the ellipse 
into bezier curves.


Tim Rowley wrote:

>The SVG specification seems vague on a couple points regarding markers:
>  * If both "marker" and "marker-*" attributes are set, which has
>    precedence?
>  * Are markers supposed to contribute to the hit testing of the
>    referencing geometry?
>Looking Adobe's SVG viewer 6.0 prerelease, I'm seeing some differences
>in interpretation of the specification from how I would read it:
>  * Do subsequent movetos generate a marker?  For example, should
>    "M 100 100 L 150 100 M 200 100 M 250 100 L 300 100" generate four
>    or five markers?  I'd say four, Adobe says five.
>  * How many markers is the elliptical arc path segment supposed to
>    generate?  For example, should "M 30 90 A 75 50 30 0 1 180 90"
>    generate two or three markers?  I'd say two, Adobe says three.
Received on Wednesday, 18 August 2004 23:56:39 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 8 March 2017 09:46:59 UTC