Class LineBreaks

Namespace

Egami.Fonts.Layout

Assembly

Egami.Fonts.dll

Finds where lines may break: Unicode's line breaking algorithm (UAX #14, Unicode 17.0) from Egami's own tables, with CSS Text 3's word-break and line-break switches. No shaping is involved, and there are no dictionaries: Thai, Lao, Khmer and Myanmar break only at spaces and zero width spaces.

public static class LineBreaks

Inheritance

object

LineBreaks

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Examples

// Where lines may end: after spaces and hyphens, and always at the end; a line must end after a newline.
List<int> breaks = [];
foreach (LineBreak b in LineBreaks.Enumerate("A well-known fact.\nNext"))
{
    breaks.Add(b.Index);                       // 2, 7, 13, 19 (mandatory), 23
}

// CSS switches: break-all lets letters break like ideographs.
LineBreakOptions breakAll = new(WordBreak: WordBreak.BreakAll);
int count = 0;
foreach (LineBreak b in LineBreaks.Enumerate("word", breakAll))
{
    count++;                                   // 4: after every letter
}

Remarks

With Strict, which is UAX #14's own rules, every break Unicode's LineBreakTest.txt lists is found; the default (CSS's auto) also breaks before small kana. An object replacement character (U+FFFC, as placeholders use) breaks before and after. The enumerator walks the text once and allocates nothing.

Methods

Enumerate(ReadOnlySpan<char>, LineBreakOptions)

Enumerates the break opportunities of a text, in order; the last is always at the end of the text.

public static LineBreakEnumerator Enumerate(ReadOnlySpan<char> text, LineBreakOptions options = default)

Parameters

text ReadOnlySpan<char>

The text.

options LineBreakOptions

The CSS switches; the default is CSS's.

Returns

LineBreakEnumerator

An enumerator of the breaks. An empty text has none.

Examples

// Where lines may end: after spaces and hyphens, and always at the end; a line must end after a newline.
List<int> breaks = [];
foreach (LineBreak b in LineBreaks.Enumerate("A well-known fact.\nNext"))
{
    breaks.Add(b.Index);                       // 2, 7, 13, 19 (mandatory), 23
}

// CSS switches: break-all lets letters break like ideographs.
LineBreakOptions breakAll = new(WordBreak: WordBreak.BreakAll);
int count = 0;
foreach (LineBreak b in LineBreaks.Enumerate("word", breakAll))
{
    count++;                                   // 4: after every letter
}