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RE: [css-round-display][motion-path] Integrate polar positioning to the motion path spec

From: Jihye Hong <jh.hong@lge.com>
Date: Mon, 20 Jun 2016 16:04:40 +0900
To: "'Brad Kemper'" <brad.kemper@gmail.com>
Cc: "'www-style list'" <www-style@w3.org>
Message-ID: <00a701d1cac2$03f3a3a0$0bdaeae0$@lge.com>
> On Jun 14, 2016, at 5:49 PM, Brad Kemper < brad.kemper@gmail.com > wrote:
> On Jun 13, 2016, at 7:57 PM, Jihye Hong <jh.hong@lge.com> wrote:
> >>> On Jun 14, 2016, at 1:12 AM, Brad Kemper <brad.kemper@gmail.com> wrote:
> >>> On Jun 13, 2016, at 2:00 AM, Jihye Hong <jh.hong@lge.com> wrote:
> >>>

> >> I didn't see anything in there about 'offset-position', which was
> >> part of the same resolution. It is supposed to be a means of positioning that is similar to how
> background-position works.
> >> You have 'offset-anchor' described as "Defines an origin of the element in the path."
> >> But as discussed, it should work with offset-position to set the
> >> alignment point of the element ('auto' for
> >> 'offset-position:<percentage>' would copy percentages from offset-position) to set the alignment
> point in the element to align to the offset-position point in the containing block).
> >
> > The name of the property which specifies the initial position of the
> > path was suggested 'offset-origin' or 'offset-position' [2].
> > As you mentioned, when the property is specified with 'offset-anchor'
> > to an element, it works similar to how 'background-position' works.
> > I wrote the property as 'offset-origin' instead of 'offset-position'.
> I see. Origin and anchor are such similar ideas, that it is very confusing having them mean such
> different things in the same spec, and trying to keep straight which is which. Especially since
> 'transform-origin' uses the word "origin" to describe what you are calling an anchor.
> Whereas "offset-position" shares a word with "background-position" that it is very similar to. It
> makes it really easy to remember that it is the one that is similar to background-position for moving
> stuff around, and not the thing that sets an alignment point. I don't have to go through the slow
> exercise of trying to remember which is which whenever I see "origin" or "anchor".

I know that you have had hard time in between 'origin' and 'anchor', and I think other people also may confuse of them.
SO, let's change 'offset-origin' to 'offset-position'! :)

> > 'offset-origin'('offset-position') doesn't matter with the origin of
> > the element. It decides the initial position of the path.
> initial position of the element, you mean? The initial start of the path (relative to the element) is
> set by 'offset-anchor', based on everything you've said so far.

What I meant is, 'offset-position' decides the initial position of the path.

In the specification of "offset-path"[1] (which refers 'motion-path'), "initial position" for the path which is the same
when 'offset-distance' is 0 is already defined.
So 'offset-position: auto' follows the definition in [1], the initial position sets to the specified position
differently according to the type of value for 'offset-path'.

> > When 'offset-origin' and 'offset-path' with <angle> is specified in an element, the position given
> by 'offset-origin'
> > works as the origin point of the coordinate system.
> We don't need to talk about coordinate systems. 'Offset-origin/position' determines the position of
> the element prior to moving  it along a path or angle. It is simpler to describe it this way, than to
> speak of new coordinate systems.

I agree with that. 

= Jihye

[1] https://drafts.csswg.org/css-round-display/#initial-position 
Received on Monday, 20 June 2016 07:05:17 UTC

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