org.apache.fop.fonts.truetype

Class CmapWriter

java.lang.Object

org.apache.fop.fonts.truetype.CmapWriter

public final class CmapWriter
extends Object

Rewrites the cmap table of an sfnt (TrueType) font so that it contains the character to glyph-index mappings held by FOP for that font, including the Private Use Area code points that MultiByteFont.createPrivateUseMapping allocates for complex-script (GSUB) output.

The AFP renderer writes text as UTF-16 code points and the AFP consumer resolves each code point to a glyph through the embedded font's cmap. Substituted glyphs are exposed by FOP as PUA code points which are, by construction, absent from the original font's cmap; without this rewrite they would not resolve.

The rewrite is deliberately minimal: the original font bytes are preserved, a fresh cmap table (a single Windows BMP, format 4 subtable) is appended on a 4-byte boundary, and only the cmap entry in the sfnt table directory is repointed to it. The original cmap bytes remain in the file as unreferenced dead space. The font's glyph numbering is left untouched, so the glyph indices line up with the embedded glyphs.

Method Summary

Modifier and Type	Method and Description
static byte[]	appendCmap(byte[] font, CMapSegment[] segments) Returns a copy of the given TrueType font whose cmap table maps the supplied segments.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

appendCmap

public static byte[] appendCmap(byte[] font,
                                CMapSegment[] segments)
                         throws IOException

Returns a copy of the given TrueType font whose cmap table maps the supplied segments.

Parameters:

font - the original TrueType font bytes (must keep its original glyph numbering)

segments - the character-to-glyph mappings to encode (original mappings plus PUA additions)

Returns:

the rewritten font bytes

Throws:

IOException - if the font has no cmap or head table