Re: [Gimp-developer] opentype ui (gimp-developer-list Digest, Vol 105, Issue 13)

[Jim DeLaHunt <list+gnome_lists_2018 jdlh com>]

On 2020-06-20 09:27, Liam R E Quin wrote:
> For some time i've been thinking about what a user interface to
> opentype features could look like.…
> Inkscape already has some opentype feature support, but i don't think
> there's a UI for choosing alternate glyphs, and i find it a little hard
> to use, but maybe that's  just me. It's a start, at least.
>
> What do you think?


A long time ago, I was a software developer in the Type Department at 
Adobe Systems, watching the type designers come up with the OpenType 
font features, and watching the Adobe InDesign and other teams design 
UIs to take advantage of OpenType features and to render text applying 
those features. Based on that, I have a few thoughts.

If you are thinking about giving Gimp users the ability to take 
advantage of the capabilities of OpenType fonts and their features, 
that's wonderful, but it's also a major UI design challenge. I would 
suggest starting with user stories. Who wants to use Gimp for this 
purpose? In what language or script? Trying to accomplish what goal?  
Based on those stories, you can decide whether the right UI is to turn 
on features and let the text rendering pick the glyphs, or to give users 
a big palette of glyphs and let them choose, or some combination of the 
two.

In general, good results from OpenType requires a cooperative text 
layout engine that has language- and script-specific rules. Those rules 
affect how it interprets the feature data in the font. Thus you 
shouldn't expect, for example, that Gimp can have a language-agnostic UI 
and text engine which will do a good job of such diverse scripts as 
Latin and Arabic. You will need to do some language- and script-specific 
UI and text engine logic.


> Inkscape already has some opentype feature support, but i don't think
> there's a UI for choosing alternate glyphs, and i find it a little hard
> to use, but maybe that's  just me. It's a start, at least.

In looking for examples and inspiration for user interaction design, I 
would nominate Adobe Indesign as probably the best design for empowering 
users to get good typography results from OpenType. Adobe invested a lot 
of effort to get that right. But that design only covers a few scripts, 
such as Latin and Japanese. It did not, in my time, cover Arabic or 
Indic scripts equally well (though Adobe might have added that later). 
Also look at LibreOffice, which has OpenType feature support which I use 
and like.


> Today i came across this Web app, which gives a possible idea for
> showing alternate glyphs, something GIMP users can't  access at all
> right now.
>
> https://alif-type.github.io/rana-kufi/app/
>
> Click on the large Arabic text to see: a list of alternate shapes
> appears beneath the selection. Sometimes there are many of them.

This app provides a fascinating visual exercise. However, my 
understanding is that Arabic script is basically calligraphy, only 
somewhat constrained by mechanistic typesetting. I imagine there is a 
lot going on with this app beyond choosing from a palette of alternate 
glyphs. Getting good results requires knowing which glyphs to choose 
from the palette.  Enabling users to get good results with Arabic script 
in Gimp will require Arabic script expertise.

In sum: typography done right is a major undertaking. It requires more 
than linking in a capable library and pasting on a simple UI.

Best regards,
        —Jim DeLaHunt, software engineer, Vancouver, Canada