Similar to the Blitz tracking issue, this is what egui will eventually need from Parley.

Parley

• Text wrap styling (Implement word-break and overflow-wrap style properties #315)
• Text truncation with ellipsis
• serde support for some types (the selection ones at least)
• Vertical alignment options, especially for InlineBox (Vertical alignment and the concept of a "parent" font and style #291)
• Ability to set line.offset? (necessary for egui's LayoutSection::leading_space)
  • This can't just be a visual thing because of hit testing; Layout needs to agree on where everything is
• Absolute line height
• Custom family names (Fontique: Support registering a font with custom family name and FontInfo #117)
• Inline box fix (Fix text editing for layouts which contain inline boxes #299)
• Don't round vertical metrics (Don't round vertical metrics #297)
• RTL jank (Backwards cursor navigation gets stuck in a loop with RTL text + newline #298)
• Support the tab character (Display tab character #302)
• AccessKit API improvements (Parley's AccessKit integration is hard to integrate with some applications #310)
• Technically Swash: tighter glyph bounds (Tighten bounds calculations and update Mask::offset documentation dfrg/zeno#15) (merged but not released)
• A newer/better "attributed text" API. Currently I'm using TreeBuilder since I need to push entire style sets at once, but TreeBuilder allocates a new String every time, which is unnecessary.

Fontique

• SystemUi doesn't properly fallback in some cases (e.g. Arabic text, macOS shortcut symbols) on my machine; SansSerif does (On Linux, GenericFamily::SystemUi should fall back to sans-serif #323)
• Size adjustment multiplier for custom fonts (Implement size-adjust property #324)

API rework?

As discussed in #325, a lot of this would be way easier to implement if Parley exposed lower-level APIs that let us position each line ourselves. In particular, egui needs to support flowing text around previous text, which I'm currently hacking together with InlineBox and shifting things around vertically.