Class FontEngine

Immutable font index + simple shaper for Word-compatible measurement over OpenType TTF/OTF/TTC sources.

public sealed class FontEngine : ITextShaper

Inherited Members: object.GetType()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Remarks

One engine instance is built once per converter instance and then used concurrently by many runs. The index is immutable after construction.

FontEngine(FontEngineOptions?, IConversionDiagnostics?): Initializes a font engine from system directories, caller-provided directories, and optional embedded font payloads.

HasScriptFallback: Gets a value indicating whether any per-script glyph-level fallback chains are configured (see ScriptFallbackFonts).

CanShape(FontFace, string?): Shapes Arabic and Hebrew through the face's own GSUB and GPOS tables - joining forms, required and standard ligatures, contextual alternates, marks and kerning - when the face has the tables, covers the script and maps the run's letters. Every other script, and every face that fails one of those tests, keeps the cmap + hmtx path byte for byte; a run the tables cannot shape (a malformed table, an exhausted work budget) falls back to it too, so shaping never turns into an exception.

Measure(ReadOnlySpan<char>, FontFace, Twips, Twips, ClusterAdvanceBuffer): Measures a run against an already resolved face into a reusable buffer.

Measure(ReadOnlySpan<char>, in FontKey, Twips, IConversionDiagnostics?): Measures a run with a logical font key and returns immutable per-cluster advances.

Measure(ReadOnlySpan<char>, in FontKey, Twips, ClusterAdvanceBuffer, IConversionDiagnostics?): Measures a run with a logical font key into a caller-provided reusable buffer.

Parse(ReadOnlyMemory<byte>, string, IConversionDiagnostics?): Parses one TTF/OTF/TTC payload into one or more FontFace instances.

Preflight(IReadOnlyList<FontKey>): Runs a font preflight over a set of requested families, returning one resolution per distinct family (first-seen order) plus aggregate substitution risk. This resolves without emitting per-run diagnostics so a caller can inspect fidelity risk before paying for a full conversion.

Resolve(in FontKey, IConversionDiagnostics?): Resolves a logical font request to a concrete face, applying Word-style fallback and synthetic bold/italic flags when exact styles are missing.

Resolve(in FontKey, out FontResolution, IConversionDiagnostics?): Resolves a logical font request and additionally reports the detailed resolution outcome (which step succeeded, the selected family, and a PANOSE distance or exact-metric flag for substitutions).

Shape(in ShapeRequest, ShapedGlyphBuffer): Shapes text through the ITextShaper seam using the provided FontFace implementation.

TryGetFontProgram(FontFace, out ReadOnlyMemory<byte>): Tries to get the font program backing a resolved face whose source is held in memory — a document-embedded payload or one of the bundled metric-compatible fonts — rather than stored as a file on disk.

WithEmbeddedFonts(IList<EmbeddedFontSource>, IConversionDiagnostics?): Returns an engine that resolves against this engine's faces plus the supplied document-embedded payloads, which take priority over everything already indexed.