[whatwg] Canvas line styles comments

Kristof Zelechovski giecrilj at stegny.2a.pl
Sat Feb 2 12:20:34 PST 2008

A pair cannot be consecutive unless it follows after another pair, 
which would be irrelevant anyway.

The rounding arc should be chosen 
so that it is not contained in the convex hull of the stroke path segments 
terminated at the points where the arc begins.


-----Original Message-----
From: whatwg-bounces at lists.whatwg.org
[mailto:whatwg-bounces at lists.whatwg.org] On Behalf Of Philip Taylor
Sent: Saturday, February 02, 2008 8:48 PM
To: Ian Hickson
Subject: Re: [whatwg] Canvas line styles comments

Some comments on the newly modified version:


"A join exists at any point in a subpath shared by two consecutive
pairs of lines." - should be "two consecutive lines" or "a consecutive
pair of lines".


"The round value means that a filled arc connecting the two corners on
the outside of the join, with the diameter equal to the line width and
the origin at the point of the join, must be rendered at joins." - if
I was being pedantic (which I am) I'd say there's two possible arcs
connecting those two corners (one clockwise, one anticlockwise), so it
should specify which one is meant. But I don't know how to easily say
that, and an implementor would have to be silly to do it the wrong
way, so maybe a precise definition isn't needed.

Should lineJoin='round';moveTo(0,0);lineTo(100,0);lineTo(0,0);stroke()
draw a semicircle at (100,0) pointing rightwards? There is no "outside
of the join" there, so the spec doesn't say what should happen.


Philip Taylor
excors at gmail.com

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