Where does FontResolver live in the IronPDF API?

FontResolver is a class in the PdfToSvg namespace, shipped in IronPdf.dll. It derives from System.Object. Obtain an instance through the static properties Default, EmbedOpenType, EmbedWoff, or LocalFonts, or subclass it using the protected constructor to create a custom resolver.

How do you choose a font embedding strategy for SVG export in C#?

Assign one of the built-in FontResolver static properties to the FontResolver option on your conversion settings before converting. Use EmbedWoff for browser-friendly self-contained SVGs, EmbedOpenType for maximum compatibility, LocalFonts to keep file size small when fonts are installed on the target machine, or Default for a general-purpose balance.

How do you implement a custom font resolver with IronPDF?

Subclass FontResolver (its constructor is protected) and override ResolveFont or ResolveFontAsync. Both methods receive a SourceFont describing the typeface found in the PDF and a CancellationToken, and must return a Font that tells the converter how to represent that typeface in the SVG output.

What is the difference between ResolveFont and ResolveFontAsync on FontResolver?

ResolveFont is the synchronous overload that returns a Font directly. ResolveFontAsync is the awaitable Task overload for use in async pipelines where blocking the calling thread is undesirable. Both accept a CancellationToken for cooperative cancellation.

Class FontResolver

Inheritance

System.Object

FontResolver

Namespace: PdfToSvg

Assembly: IronPdf.dll

Syntax

public abstract class FontResolver : Object

Font handling during PDF-to-SVG conversion is governed by a FontResolver, the policy object that decides how each typeface embedded in a source PDF is represented in the output SVG. Choosing the right resolver controls file size, offline rendering fidelity, and cross-platform text accuracy without touching any other part of the conversion pipeline.

Four built-in resolvers cover the most common scenarios. FontResolver.Default applies a balanced strategy suited to general-purpose conversion. FontResolver.EmbedOpenType encodes each font as a base64 OpenType data URI inside the SVG, making the file self-contained and portable at the cost of a larger payload. FontResolver.EmbedWoff does the same with WOFF encoding, which compresses better and is the preferred choice when the SVG will be displayed in a browser. FontResolver.LocalFonts emits CSS local() references instead of embedding data, keeping the SVG compact but requiring that the same fonts are installed on every machine that renders the file.

Pass a resolver to the conversion options when converting a PDF with IronPDF. The resolver is consulted once per distinct SourceFont encountered in the document. ResolveFont returns a synchronous Font decision, while ResolveFontAsync is the awaitable overload for pipelines that must stay non-blocking, both accepting a CancellationToken for cooperative cancellation.

Custom font strategies are possible by subclassing FontResolver (the constructor is protected) and overriding ResolveFont or ResolveFontAsync. A custom resolver can, for example, substitute a licensed typeface, strip a font entirely, or fetch a font from a remote asset store.

using PdfToSvg;

// Embed fonts as WOFF for browser-friendly, self-contained SVG output
var options = new ConversionOptions
{
    FontResolver = FontResolver.EmbedWoff
};

using var pdf = PdfDocument.FromFile("report.pdf");
string svg = pdf.Pages[0].ToSvgString(options);
File.WriteAllText("report.svg", svg);

The IronPDF get-started guide covers initial setup, the PDF-to-SVG how-to explains the full conversion workflow, and the font handling example demonstrates each resolver side by side.

Constructors

FontResolver()

Declaration

protected FontResolver()

Properties

Default

Declaration

public static FontResolver Default { get; }

Property Value

Type	Description
FontResolver

EmbedOpenType

Declaration

public static FontResolver EmbedOpenType { get; }

Property Value

Type	Description
FontResolver

EmbedWoff

Declaration

public static FontResolver EmbedWoff { get; }

Property Value

Type	Description
FontResolver

LocalFonts

Declaration

public static FontResolver LocalFonts { get; }

Property Value

Type	Description
FontResolver

Methods

ResolveFont(SourceFont, CancellationToken)

Declaration

public virtual Font ResolveFont(SourceFont sourceFont, CancellationToken cancellationToken)

Parameters

Type	Name	Description
SourceFont	sourceFont
System.Threading.CancellationToken	cancellationToken

Returns

Type	Description
Font

ResolveFontAsync(SourceFont, CancellationToken)

Declaration

public virtual Task<Font> ResolveFontAsync(SourceFont sourceFont, CancellationToken cancellationToken)

Parameters

Type	Name	Description
SourceFont	sourceFont
System.Threading.CancellationToken	cancellationToken

Returns

Type	Description
System.Threading.Tasks.Task<Font>