[RFC] Bold Border

[chshersh]

GitHub TUI has some elements inside a border like this one:

github-tui/lib/tui/widget/widget.ml

Lines 29 to 34 in deb91b8

	let code_tab ~is_selected =
	tab_doc ~is_selected
	[ "╭───────╮";
	"│ Code¹ │";
	"└───────┴";
	] [@@ocamlformat "disable"]

Sometimes those elements are selected and I would love to have a bold border for them.

Unfortunately, the bold ANSI sequence doesn't make borders bold! I need to use different characters like ┏━┓ instead of ┌─┐.

This issue is to discuss possible options to implement this inside GitHub TUI.

Option 1: Traverse the sequence of graphemes

Recent migration to ansifmt enabled to introspect easily the current applied formatting. A simple solution would be to check if the current chunk is bold and if yes, convert to a list of graphemes and replace border characters with new ones and convert back here:

github-tui/lib/pretty/chunk.ml

Line 6 in deb91b8

let fmt { styles; string } = Ansifmt.Styling.wrap ~contents:string styles

It may seem costly to traverse every single chunk but since TUI is not exactly huge, maybe it'll be fine. But it's the simplest non-invasive solution.