D3665: graph: improve graph output by using Unicode characters

[indygreg (Gregory Szorc)]

indygreg requested changes to this revision.
indygreg added a comment.
This revision now requires changes to proceed.


  I think having better display of graph symbols is a compelling end-user feature and should be part of Mercurial.
  
  It is apparent that no set of advanced glyphs works in all terminals and fonts. But that shouldn't mean people can't opt in to using more visually appealing glyphs in graph output.
  
  I think this extension is a step in the right direction. But I also don't feel comfortable exposing this extension to all users just yet because of the many environments it doesn't work in.
  
  If we add `(EXPERIMENTAL)` to the first line of the module docstring (so it doesn't show up in `hg help` output), I'm comfortable accepting this extension as is. We can remove the experimental state of the feature once support for customizing glyphs is added. That can be done in the extension or (preferably) in core, alleviating the need for an extension.
  
  While I'm here, I think a reasonable follow-up feature would is to have built-in "profiles" for graph glyphs so users could e.g. start with a set of glyphs that are known to work reasonably well given a certain terminal emulator, font, etc. We could also provide a `hg debuggraphlog` or similar that printed examples of the various built-in profiles so users could pick one that renders the best. This could be exposed via a `ui.graph-symbols` config option or similar.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3665

To: johnstiles, #hg-reviewers, spectral, indygreg
Cc: quark, spectral, indygreg, smf, yuja, mercurial-devel