[ttml2] lineHeight normal algorithm and fontSelectionStrategy (#1102)

nigelmegitt has just created a new issue for https://github.com/w3c/ttml2:

== lineHeight normal algorithm and fontSelectionStrategy ==
Currently the `tts:fontSelectionStrategy` attribute is not listed in the algorithm for `normal` in `tts:lineHeight` but since that algorithm (step 4) is based on actual fonts chosen, it should be.

### Algorithm should take include `tts:fontSelectionStrategy`

The algorithm for computing the used value at https://www.w3.org/TR/ttml2/#style-attribute-lineHeight lists in step 4:

> the computed values of the `tts:fontStyle`, `tts:fontWeight`, and `tts:fontVariant` style properties of P. 

This should additionally include `tts:fontSelectionStrategy`.

### Consistency of referencing back to the algorithm.

[`tts:fontFamily`](https://www.w3.org/TR/ttml2/#style-attribute-fontFamily) and [`tts:fontWeight`](https://www.w3.org/TR/ttml2/#style-attribute-fontWeight) and
[`tts:fontVariant`](https://www.w3.org/TR/ttml2/#style-attribute-fontVariant) all include text like:

> In addition to applying to span, the computed value of this property on a `p` element is used to resolve the normal value of the style property associated with the `tts:lineHeight` attribute as specified in 10.2.27 `tts:lineHeight`.

This should be added to [`tts:fontSelectionStrategy`](https://www.w3.org/TR/ttml2/#style-attribute-fontSelectionStrategy)

Please view or discuss this issue at https://github.com/w3c/ttml2/issues/1102 using your GitHub account

Received on Tuesday, 28 May 2019 10:25:12 UTC