Re: specification for Mozilla's SVG in OpenType proposal

Tal Leming wrote:

> The duplication of data has historically been a problem. For an example,
> go look through the OpenType spec and tell me where to find the descender
> value for a font. I'll wait until you have an answer.... Back? Okay, what's
> your answer? Nope. That's not the right answer. :-) There is no right
> answer because the descender can be specified in several places. In the
> past and present (and probably future) different
> OS/applications/environments pulled the value from different places. The
> value is stored differently in different places and that has led to
> rendering inconsistencies. That's bad. Even if you state in the spec that
> the hmtx value should be used and the values must be consistent, someone
> will make a mistake and pull the value from the wrong place.
>

Yes, we definitely don't want to make that worse.

Also, from an implementation point of view, it is much easier to simply
carry on using the OpenType metrics than to allow metrics data to come from
the SVG as well.

I strongly disagree that this is not critical. Think about a workflow that
> doesn't allow these colors to be changed externally:
>
> 1. user wants to change the shadow color of a font
> 2. they have to download and install some software
> 3. they have to figure out how this software works
> 4. they have to modify the font and create a new version
> 5. they have to upload the new font
>
> Designers/authors by and large don't want to make fonts. They want to use
> them. Telling them that they have to jump through hoops to make the text
> color match the color scheme of the website they are working on is...ouch.
>

I don't think it's critical because this proposal already addresses many
use-cases; the ability to pass in more than one color is not supported by
any other proposal; and it can be added to this proposal later without
breaking things.

More details on the use-cases here would be helpful. For example I believe
some use-cases that seem to require multiple input colors could be
addressed by using SVG filters to modify (e.g. darken) the context-color.

Rob
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