Text rendering

[kpreid]

As discussed in 95a1578, I am adding Primitive::Text, text rendering in blocks without rendering to an intermediate space, for more efficient rendering and better interactive editability. The feature needs work:

• Specify text positioning via a bounding box, so that we can tolerate font changes better and more reasonably specify location (b2ef581)
• Optional truncation/ellipsis of long text
• Usage and demos:
  • Add a vui::widgets::Label that displays static text blocks from a string. (03fd53f)
  • Add a vui::widgets::TextBox that displays dynamic and eventually editable text.
  • Add text labels to vui::widgets::*Button. (84e3322)
  • Replace all or most existing text rendering
• Resolution and Z/depth issues:
  • Explicitly chosen resolution / text sizing within block
  • Add a means to get outlined text (as used in the existing tooltip and logo) efficiently — this will increase thickness
  • We may want characters to be able to have depth themselves (3D emoji)
  • Flag indicating intent to engrave the text, so all features should touch the front face and be legible as monochrome
• Fonts (and eventually replacing embedded-graphics — Replace embedded-graphics dependency #528)
  • Create or find a good set of “system fonts”
  • Add user-defined font support
• Specify, test, and demonstrate the layout of multiline text
• Fix numeric overflows possible by large layout numbers (see b4ebb67)

[kpreid]

As of 1791e75 we have a Label widget, and each Text has a layout_bounds box and resolution.

[kpreid]

f4e256c adds outlined text. However, I ran into trouble trying to actually use it for the Tooltip widget — nothing is visible even though all the layout looks correct. (The bug is not specific to outlined text.) I think I need better debugging tools for block definitions — some kind of “why is this invisible” report.

[kpreid]

84e3322 adds text for button labels (but much work is needed on tuning the layout).

[kpreid]

570d7df converts the Tooltip widget to use text blocks. It reveals our lack of proper bounding box handling for outlined text.