Styling

TextStyle

TextStyle is the immutable style record behind every text-bearing element (Paragraph, Heading, PageNumberText, list items, table cells). TextStyle.Default is used when an element doesn’t specify one:

Derived, read-only properties:

• LineHeightPx = FontSizePx * LineHeightMultiplier.
• HorizontalInsetPx = left+right margin + left+right padding - what’s subtracted from the container width before word-wrapping.
• VerticalInsetPx = top+bottom margin + top+bottom padding - what’s added on top of the wrapped text’s height when measuring the element.

Call style.With(...) to derive a modified copy - every property above has a matching nullable parameter, so style.With(fontSizePx: 18) changes only the font size.

Fluent modifiers (TextElementBuilder)

AddParagraph/AddHeading/AddText/AddPageNumber all return a TextElementBuilder, which exposes:

c.AddParagraph("Note")
    .AlignCenter()      // AlignLeft / AlignCenter / AlignRight / AlignJustify
    .Bold()              // FontWeight.Bold
    .Italic()            // FontStyle.Italic
    .FontSize(16)         // px
    .FontColor("#b23b3b") // any CSS color
    .FontFamily("Georgia, 'Times New Roman', serif")
    .MarginTop(8).MarginRight(0).MarginBottom(8).MarginLeft(0)
    .Margin(8)                    // uniform, all four sides
    .Margin(8, 0, 8, 0)           // top, right, bottom, left (CSS shorthand order)
    .Padding(12)                  // uniform
    .Padding(12, 8, 12, 8);       // top, right, bottom, left

Each call rebuilds the element with an updated TextStyle and replaces it in the owning content/section list - see Core Concepts: The rebuild-and-replace pattern for why this is safe to chain repeatedly. Because each call only overrides what you pass, calling the same modifier twice just has the later value win (no accumulation).

Margin vs. padding

Both shrink the space available to the text, but at different edges of the element’s box:

• Margin is space outside the element’s own box - it pushes the box away from its container’s edge (left/right margin) or from neighboring elements (top/bottom margin). MarginBottomPx defaults to 8, which is why elements added via AddParagraph/AddHeading in Content get natural spacing between them with no extra effort.
• Padding is space inside the element’s own box - it insets the text from the box’s own edges without affecting where the box itself sits relative to its neighbors. Padding is what you’d reach for to inset text away from a border or a colored background you’ve drawn around it (e.g. with AddRawHtml, or a RawHtml-wrapped frame).

Text wraps within whatever width is left after both are subtracted from the container width (HorizontalInsetPx), and the element’s measured height includes both (VerticalInsetPx).

Default margins differ between builders. ContentBuilder.AddParagraph/AddHeading default to TextStyle.Default/TextStyle.ForHeading(level), which both carry the normal bottom margin. PageSectionBuilder.AddText/AddPageNumber and RowColumnBuilder.AddText/AddHeading/AddPageNumber instead default to marginBottomPx: 0 - a header/footer line or a row column’s stacked content usually shouldn’t have an implicit gap after the last line the way body content does. Pass an explicit TextStyle (or chain .MarginBottom(...)) if you want different spacing in those contexts.

The heading scale

TextStyle.ForHeading(HeadingLevel) is the default style scale used by AddHeading when you don’t pass an explicit TextStyle:

Pass a TextStyle explicitly to AddHeading(text, level, style) to override any of these while keeping the semantic <h1>-<h6> tag the level implies.

Images

AddImage/AddImageFromBase64 return an ImageElementBuilder:

c.AddImage("logo.png", widthPx: 96)
    .AlignCenter()              // AlignLeft (default) / AlignCenter / AlignRight
    .Margin(8)
    .MarginBottom(16)
    .Padding(4);

• Alignment only has a visible effect when the image’s container (content width, or a row column’s width) is wider than the image itself - it positions the image’s box within the leftover space. Justify behaves the same as Left.
• Margin shrinks the available width from the container’s edges (left/right) and adds vertical space around the image (top/bottom), exactly like text margins. The default is MarginBottomPx: 8 (and 0 elsewhere) on ReportImage.
• Padding insets the image itself from its own box, which only matters in combination with alignment (it shifts where centering/right-alignment measures from) since an image with no visible border or background otherwise has nothing to “pad away from”.

Model type: ReportImage.

Rows and row columns

AddRow returns a RowHandle with margin modifiers for the row as a whole:

c.AddRow(row => { ... }).Margin(12).MarginTop(20);

RowBuilder.AddColumn returns a RowColumnHandle with padding modifiers for that one column’s inset from its own edges:

row.AddColumn(col => col.AddText("Hi")).Padding(8);

See Rows and Columns for the full picture, including how column width and vertical alignment interact with these.

Table styling

TableStyle (header/cell text styles, striping, borders, cell padding, and RowSplitBehavior) is its own topic - see Tables: TableStyle.

Colors and fonts: a caveat

Every color in this library is a plain CSS color string passed straight through to inline styles - there’s no validation, palette, or theme system. Likewise, FontFamily is an opaque CSS font-family list: the library doesn’t ship or embed any fonts, so whatever you specify must be available in whichever browser/engine ultimately renders the HTML (or it falls back per normal CSS font-family rules).

This also matters for pagination accuracy: the bundled ApproximateTextMeasurer estimates wrapping using a single generic sans-serif metrics table regardless of which FontFamily you set - changing fonts changes how the text looks but not how the engine predicts it wraps. See Text Measurement for what this means in practice and how to get pixel-exact pagination if you need it.

Where to go next

• Tables for TableStyle and per-cell overrides.
• Rows and Columns for RowVerticalAlignment and column width resolution.
• Text Measurement for how font choice interacts with pagination precision.

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