Show baseline (and alignment lines and zones)

[BlackFoundry]

• ascender
• descender
• cap height
• x-height
• blue zones?

Perhaps relates to custom guidelines.

[BlackFoundry]

Read FontInfos to show various alignement lines and zones. Question of variations across the design-space…

[justvanrossum]

Baseline we have:

[BlackFoundry]

yes but we need xheight, descender, and cap-height, etc.

[BlackFoundry]

Related to #907

[bghryct]

Most of this is available now right? Blue zones are the only missing feature I think

[justvanrossum]

Yes indeed, looks like we forgot to link this issue to #1405.