Doug Kerr wrote:I'm not sure there is such a thing as the "Windows Drawing System", although the GDI (graphics device interface) sort of has that mantle.
Thanks for clarifying Doug. GDI is the system to which I was referring, but my Windows parlance is far behind my Mac lingo.
Doug Kerr wrote:In my Windows-based vector illustration program (Micrografx Designer 7.1), one can in fact apply a round end to a finite-width stroke open path. One can also have a closed path with a finite-wide stroke and apply a round join to the joints (although there happens to be a bug in it).
I'm not familiar with the term "finite-width stroke."
This is contrasted with a path that is (in my drawing program) defined as of "hairline width" (numerically: width =0), meaning mathematically of zero width, to be actually presented as the smallest pixel width that makes it reasonably visible at the scale of viewing or printing. (More about this later.)
Doug Kerr wrote:The bug is that the round join doesn't happen at the joint that is somehow deemed "last". My workaround is that after the path is finished, I break it in the middle of a segment. That becomes the "last" joint and is where the round join fails. But since that it just a "continuation"of the path (control vectors collinear, for one thing), the shape of the join there is moot.
If I have to modify the shape of the figure, I delete the added joint, reshape the real figure, and then put the extra joint back in.
Don't quite follow. I've never had to tinker with an open path to get caps to work. Are you using cap styles are for open paths, and controlling angled joins with the Line Join styles? (sometimes called miters.)
Firstly, this applies to a closed path join, not an open path. (I may have not made that clear.)
In any case, don't get tangled up by this. This is a bug in my drawing program, not any conceptual notion or a property of the curve defining language. (And I find just now there is in fact a way to avoid it, other than the "kludge" I described to you before.)
As a matter of interest:
I have the choice of three kinds of caps for a curve: flat, square (extends beyond the anchor point by half the width of the stroke) and round.
I have the choice of three kinds of joins for curves (whether the overall curve is closed or open): round, bevel, or miter.
If I am working with zero-width paths, I can still set both the cap and join property, and they remain properties of the curve or figure, but have no significance while the stroke width remains at zero. But if I later set a finite stroke width, those properties come into effect.
Sorry to have set you off on a wild goose chase.