Add a FontForge style spacing, metrics, and kerning window

[eliheuer]

FontForge has a useful metrics window for editing spacing, metrics, and kerning. Previewing text and testing how the font will look in different text string combinations is another use of this window. A tool of this kind is usually expected by users of font editing software.

RoboFont also has a window in this style, which last time I used RoboFont was called the "spacecenter."

[davelab6]

Fontographer is also worth a comparison.

However, as I wrote on the Glyphr Studio issue tracker, multi glyph canvas (which Fontforge also has) maybe superior.

Both is good.

[cmyr]

I'd like to start working on this shortly; my initial focus will just be on a 'preview window' that shapes some editable text, and this can then expand to allow editing of sidebearings and kerning; the underlying implementation could also then be the basis for a 'text tool' in the canvas, if we go that route. My intention is also that this can be used as a standalone tool, if that is desirable.

@eliheuer happy to talk through the design of this at some point, if you like?

[eliheuer]

I like the idea of having a standalone tool for this. I'm happy to help figure out the design, will try to do some UI wireframes after I'm done with my current freelance project.

The text tool in the editor would be nice to plan for!

[davelab6]

https://github.com/glyphr-studio/Glyphr-Studio-1/issues/94 is the issue I was referring to last year.

Note to self: The help pages for various editors would also be good to review.

• https://robofont.com/documentation/workspace/space-center/
• https://robofont.com/documentation/building-tools/toolspace/mojo/space-center/
• https://extensionstore.robofont.com/extensions/metricsMachine/
• https://help.fontself.com/en/articles/981232-kerning
• https://www.high-logic.com/fontcreator/manual11/fc_automatic_opentype_layout_feat_2_3_2.html
• https://glyphsapp.com/learn/kerning
• https://help.fontlab.com/fontlab/7/manual/Editing-Kerning/

[xorgy]

It'd be interesting to use HarfBuzz or some such similar actual high quality shaper, in the preview/metrics/multi-glyph editor/whatever views. It would be really nice to have a live specimen that respects kern/gpos/composite glyphs.

[cmyr]

The preview window is using HarfBuzz, although we're only doing the absolute minimum in terms of opentype tables at the moment.