struct TermBuf::Unicode::WidthPolicy

• TermBuf::Unicode::WidthPolicy
• Struct
• Value
• Object

Overview

How a particular terminal measures a grapheme cluster.

UAX #29 says where a cluster ends and UAX #11 says how wide a character is. Neither says what a terminal does with four emoji joined by zero width joiners, and terminals disagree: some advance two columns, some eleven. A buffer measuring a cluster differently from the terminal drawing it has every later cell on that row in the wrong place, so the measurement has to come from the terminal rather than from the standard.

WidthProbe fills one of these in by asking. The defaults are what a current terminal does, and what a terminal that answers nothing is assumed to do.

Defined in:

Constant Summary

DEFAULT = new

What a current terminal does.

NAMES = ["ambiguous_wide", "emoji_presentation", "joined_emoji", "regional_indicators", "spacing_marks"] of ::String

Every rule by name, for diagnostics and for TERMBUF_WIDTHS to check against.

Constructors

• .new(ambiguous : Int32 = 1, emoji_presentation : Bool = true, joined_emoji : Bool = true, regional_indicators : Bool = true, spacing_marks : Bool = true)

Instance Method Summary

• #ambiguous : Int32

  Cells an East Asian Ambiguous character takes.

• #copy_with(ambiguous : Int32 = @ambiguous, emoji_presentation : Bool = @emoji_presentation, joined_emoji : Bool = @joined_emoji, regional_indicators : Bool = @regional_indicators, spacing_marks : Bool = @spacing_marks) : WidthPolicy
• #emoji_presentation? : Bool

  Whether U+FE0F widens a pictograph that would otherwise be text.

• #enabled?(name : String) : Bool

  Whether the rule name is on.

• #joined_emoji? : Bool

  Whether an emoji sequence joined by U+200D collapses to the width of one emoji.

• #regional_indicators? : Bool

  Whether a pair of regional indicators collapses to one flag.

• #spacing_marks? : Bool

  Whether a spacing mark takes a cell beside its base rather than none.

• #to_s(io : IO) : Nil

  Same as #inspect(io).

• #with(name : String, enabled : Bool) : WidthPolicy

  The flags by the names TERMBUF_WIDTHS uses.

Constructor Detail

Instance Method Detail