Class RichTextBuilder

Namespace

Egami.Fonts.Layout

Assembly

Egami.Fonts.dll

Builds a RichText: Push(TextStyle) a style, Append(string) text, Pop() back to the enclosing style. Styles nest: a pushed style's unset fields come from the one it is pushed on, and the result has one flat span per stretch of equal style.

public sealed class RichTextBuilder

Inheritance

object

RichTextBuilder

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Examples

// Font families come from a collection; later families cover what the first lacks.
FontCollection fonts = new();
fonts.AddFile(System.IO.Path.Combine(folder, "NotoSans-Regular.ttf"));
fonts.AddFile(System.IO.Path.Combine(folder, "NotoSansArabic-Regular.ttf"));
fonts.TryGetFamily("Noto Sans", out FontFamily latin);
fonts.TryGetFamily("Noto Sans Arabic", out FontFamily arabic);

// Styles nest: the inner span keeps the outer one's size and adds a color and an underline.
RichText text = new RichTextBuilder()
    .Append("Peace is ")
    .Push(new TextStyle { Size = 20 })
    .Append("\u0633\u0644\u0627\u0645 ")
    .Push(new TextStyle { Color = new Rgba8(200, 30, 30, 255), Decoration = new TextDecoration() })
    .Append("in Arabic")
    .Pop()
    .Pop()
    .AddPlaceholder(new Placeholder(16, 16, PlaceholderAlignment.Middle))
    .ToRichText();

ParagraphStyle style = new()
{
    DefaultStyle = new TextStyle { FontFamilies = [latin, arabic], Size = 16, LineHeight = LineHeight.Multiple(1.4f) },
    Align = TextAlign.Justify,
    LineBreaking = new LineBreakOptions(WordBreak: WordBreak.Normal),
};

// Shaped once: lay it out at any width later.
Paragraph paragraph = Paragraph.Create(text, style);

Properties

Depth

Gets the number of styles pushed and not popped.

public int Depth { get; }

Property Value

int

Length

Gets the length of the text so far, in UTF-16 units.

public int Length { get; }

Property Value

int

Methods

AddPlaceholder(Placeholder)

Adds an inline box, as a U+FFFC in the current style.

public RichTextBuilder AddPlaceholder(Placeholder placeholder)

Parameters

placeholder Placeholder

The box.

Returns

RichTextBuilder

This builder.

Append(ReadOnlySpan<char>)

Appends text in the current style.

public RichTextBuilder Append(ReadOnlySpan<char> text)

Parameters

text ReadOnlySpan<char>

The text.

Returns

RichTextBuilder

This builder.

Exceptions

ArgumentException

The text contains U+FFFC, which only AddPlaceholder(Placeholder) adds.

Append(string)

Appends text in the current style.

public RichTextBuilder Append(string text)

Parameters

text string

The text.

Returns

RichTextBuilder

This builder.

Exceptions

ArgumentException

The text contains U+FFFC, which only AddPlaceholder(Placeholder) adds.

Pop()

Ends the last style pushed.

public RichTextBuilder Pop()

Returns

RichTextBuilder

This builder.

Exceptions

InvalidOperationException

No style is pushed.

Push(TextStyle)

Starts a style; text appended until the matching Pop() takes it.

public RichTextBuilder Push(TextStyle style)

Parameters

style TextStyle

The style; unset fields come from the style it is pushed on.

Returns

RichTextBuilder

This builder.

Exceptions

ArgumentNullException

style is null.

ToRichText()

Builds the rich text; styles still pushed end with the text.

public RichText ToRichText()

Returns

RichText

The rich text.