Re: [round-display] [motion-path] Orientation of elements due to merging polar positioning and motion path

On 05/16/2016 04:49 PM, Myles C. Maxfield wrote:
> I was thinking about our resolution from last week to merge the
> polar positioning properties from CSS Round Display[1] into
> the Motion Path[2] properties.
>
> The spec of CSS Round Display describes polar positioning as a
> way to position an element. It doesn’t seem to mention the
> orientation of the positioned element changing at all. This is
> consistent with the green box in drawn in Example 8[3].
>
> However, this is not true of motion path. In motion path, Example 1[4]
> shows the orientation of the airplane changing to face the path.
>
> According to the text of the “motion-rotation” property[5],
> the polar-angle behavior can be achieved with “motion-rotation:
> 0deg;”. However, the syntax here doesn’t agree with the values’
> explanation in the spec text - the syntax should be:
> “[[ auto | reverse ]? <angle>?]!”
>
> Given that rectangular displays are much more common on the Web
> than round displays (and this will likely continue to the the
> case into the far future), the default behavior should be the
> motion path behavior. Therefore, the default value after the
> merge should be “auto”.

While I agree we should fix the spec problems preventing this,
I don't agree with your conclusion about the initial value.
It is not always appropriate to rotate the element to fit the
path -- sometimes you do want it to stay up; it is not always
an airplane! It could very well be a set of photos spiraling
into their final positions. Or many other such things. Imho
having the motion-rotation property default to no rotation is
a very sensible choice even ignoring the existence of polar
positioning.

Also, I would suggest that the property values be
   none | auto | reverse
with the initial value as none, as I don't really see a use case
for <angle> values here: a fixed rotation should be handled with
the 'rotate' property.

~fantasai

Received on Tuesday, 17 May 2016 00:45:39 UTC