Character and paragraph formatting

Authored appearance uses platform-independent RichCharacterStyle, RichParagraphStyle, RichColor, RichLength, and RichFontSize. Colors are RGB. Lengths are stored in twips (1/20 point), and font sizes in half-points. View geometry uses device-independent display units.

Every cascading property is a StyleValue<T>:

Value	Meaning
Default / `Inherit`	Use the preceding cascade value
Explicit value	Apply that value, including false, zero, or null where supported
`Initial`	Apply the schema's initial value

editor.ApplyCharacterFormat(new RichCharacterStyle
{
    Bold = true,
    Italic = false,
    Foreground = new RichColor(30, 60, 120),
    Underline = RichUnderline.Single,
});

At an empty text selection, character commands change the session's typing format. For selected content, they create an authored transaction. ToggleBold, ToggleItalic, and ToggleUnderline resolve current formatting before choosing the new value.

Reusable styles

RichStyleSheet contains named paragraph and character definitions with BasedOn and NextStyle references. Inheritance must be acyclic. The cascade applies document defaults, paragraph styles and overrides, then inline character styles and direct overrides. ResolveCharacter, ResolveParagraph, and selected-format queries expose resolved values.

Use SetStyles, SetParagraphStyle, SetCharacterStyle, SetCharacterFormat, and SetParagraphFormat inside a rich edit. Set-format operations replace the specified direct record; preserve other direct properties explicitly when modifying only part of it. Changing a style affects all content that references it.

Character support includes bold, italic, underline variants/colors, strike-through, foreground/highlight, shading, baseline/script placement, spacing, horizontal scaling, language, direction, capitals, outline, shadow, and hidden state. Paragraph support includes alignment, direction, indents, before/after spacing, line spacing, tabs/leaders, headings, keep/widow settings, hyphenation, shading, and uniform borders.

FontFamily, FontSize, and TextColor on the view are fallback appearance and do not change saved content. Presentation layers compose afterward. Native engines can approximate some retained properties; see RTF support.

For a light/dark app theme, bind the editor's fallback text color and background together. Explicit colors in the document keep their authored values.

<rich:RichEditor
    TextColor="{AppThemeBinding Light=Black, Dark=White}"
    BackgroundColor="{AppThemeBinding Light=White, Dark=#192933}" />

Body text wraps within the editor's available width, accounting for paragraph indents. Table text uses the cell's width. Alignment does not change font size: each paragraph's text keeps its resolved character formatting.

Table of Contents

Character and paragraph formatting

Reusable styles