Table of Contents

Exceptions

Namespace: KernSmith

KernSmith throws a small hierarchy of exceptions for generation errors. All derive from BmFontException, so catching that one handles every KernSmith-specific failure.

Exception
└── BmFontException
    ├── FontParsingException
    ├── RasterizationException
    └── AtlasPackingException

try
{
    var result = BmFont.Generate("font.ttf", new FontGeneratorOptions { Size = 32 });
}
catch (FontParsingException ex)
{
    // The font file is corrupt, unsupported, or missing the requested face/system font.
}
catch (BmFontException ex)
{
    // Any other KernSmith generation failure (rasterization, atlas packing).
}

Argument validation (null arguments, out-of-range size, non-positive texture dimensions, invalid feature combinations) throws standard BCL exceptions such as ArgumentNullException, ArgumentOutOfRangeException, and InvalidOperationException rather than BmFontException.

BmFontException

The base type for all KernSmith errors. Catch this to handle any generation failure.

Member Description
BmFontException(string message) Error with a message.
BmFontException(string message, Exception inner) Error wrapping an underlying exception.

FontParsingException

Thrown when a font cannot be read. This is the most common KernSmith exception. It is raised when:

  • font data is too small, has an invalid sfnt magic, or is missing a required table (head, cmap) during TTF/OTF parsing;
  • a WOFF file is malformed, or the input is WOFF2 (which is not supported);
  • a requested face index is out of range for a .ttc/.otc collection;
  • a backend fails to initialize the font (e.g. FreeType or StbTrueType load failure);
  • a requested system font family is not installed and is not registered.
Member Description
FontParsingException(string message) Error with a message.
FontParsingException(string message, Exception inner) Error wrapping an underlying exception.
FontParsingException(string tableTag, int offset, string details) Error at a specific table and byte offset.
TableTag string? -- the font table that failed, if known (e.g. "GPOS").
Offset int? -- byte offset of the error, if known.

RasterizationException

Thrown when a glyph cannot be rendered from the font.

Member Description
RasterizationException(string message) Error with a message.
RasterizationException(string message, Exception inner) Error wrapping an underlying exception.
RasterizationException(int codepoint, string details) Error for a specific failing codepoint.
Codepoint int? -- the Unicode codepoint that failed to render, if known.

AtlasPackingException

Thrown when glyphs do not fit into the texture atlas -- for example, when rendering into a fixed target region too small for the glyphs. Try a larger max texture size.

Member Description
AtlasPackingException(string message) Error with a message.
AtlasPackingException(string message, Exception inner) Error wrapping an underlying exception.
AtlasPackingException(int glyphWidth, int glyphHeight, int maxTextureSize) Error for a single glyph too large for the texture.
GlyphWidth int? -- width of the glyph that did not fit, if known.
GlyphHeight int? -- height of the glyph that did not fit, if known.
MaxTextureSize int? -- the max texture dimension that was exceeded, if known.
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