[html5] Points in a <CANVAS> element

[John S. Urban]

The HTML5 specification appears to say to ignore a line composed of just a moveTo() call in a <CANVAS> element,
but both the opera(1) and firefox(1) browsers appear to ignore any polyline that does not change the position. That is,
    moveTo(x,y) lineTo(x,y)
does not produce a point. I think it should.

I have been collecting my experiences with the <CANVAS> implementations in the opera(1) and firefox(1) browsers at
   http://home.comcast.net/~urbanjost/canvas/canvas1.html
where I have this note ...

# POINTS: Neither browser showed a line of zero length, even when it contained two points (The HTML5 proposal currently says to ignore a path with "less than two" points in it; it does not imply lines of null length are ignored though). In order to make points easy to render I think a path composed of just a move and/or a move and then draws(s) to the same point should show a circle with a diameter equal to the current line width or a square with a side equal to the current line width or a minimum of one unit (or pixel) in order to make points visible. Maybe an option to display markers of different styles at such "points" would be nice (an X, a +, a hollow circle, ...)

I am currently working around this by processing all my polylines thru JavaScript procedures. Look at the
example at
  http://home.comcast.net/~urbanjost/canvas/vogle4.html
that makes simple points show up. Does anyone else think the browsers are wrong in not making a point or marker
to represent polylines whose elements all have the same coordinates?

Why would someone put a moveTo() in a file without intending it to render something?


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