THPDFFontDecoder Record

Holds the resolved decode tables and width metrics for a single loaded PDF font, built by the font decode fallback chain

Declaration

THPDFFontDecoder= record
  FontKey: AnsiString;             // resource key (e.g. /F1) for diagnostics
  Subtype: AnsiString;             // Type0, Type1, TrueType, CIDFontType2
  Strategies: THPDFFontStrategies; // which fallbacks are populated
  ToUnicodeMap: THPDFCMapParseResult;
  EncodingMap: THPDFCMapParseResult;        // /Encoding stream or named CMap
  PredefinedEncoding: AnsiString;           // 'WinAnsiEncoding' etc
  CIDToGIDIdentity: boolean;
  CIDToGIDs: array of Word;                 // binary CIDToGIDMap stream
  CIDToUnicode: THPDFCIDToUnicodeTable;     // cid2code.txt fallback
  GlyphNameUnicode: array[0.. 255] of Cardinal;
  GIDToUnicode: THPDFUnicodeByGID;
  // v2.505.0 simple-font /Widths (PDF 1.7 9.6.3 Table 111). Index =
  // (code - FirstChar); values are 1/1000-em glyph advances. Empty when
  // the font has no /Widths array (the interpreter falls back to 0.5*fs)
  Widths: array of Double;
  FirstChar: Integer;
  LastChar: Integer;
  CIDWidths: THPDFCIDWidthRanges;
  CIDDefaultWidth: Double;
  // Vertical (WMode 1) counterparts from the descendant CIDFont /W2 and
  // /DW2 (ISO 32000-1 9.7.4.3). Each /W2 metric is a [w1y v1x v1y]
  // triple: w1y is the displacement along the writing axis, v1x/v1y the
  // position vector from the glyph's horizontal origin to its vertical
  // origin. A range entry (cFirst cLast w1y v1x v1y) stores one triple;
  // a list entry (c [w1y v1x v1y ...]) stores one triple per CID from
  // FirstCID to LastCID. VerticalWriting gates the resolver's vertical
  // branch
  CIDVertWidths: THPDFCIDWidthRanges;
  CIDVertDefaultAdvance: Double;       // /DW2 w1y (second entry); default -1000
  CIDVertDefaultOriginY: Double;       // /DW2 v1y (first entry); default 880
  VerticalWriting: boolean;
  Ascent: Double;
  Descent: Double;
  HasVerticalMetrics: boolean;
  CodeUnitBytes: Integer;                    // bytes per char code
  OK: boolean;
end;

Unit

HPDFTextExtraction

Fields

Field	Purpose
`FontKey`	Resource key such as `/F1` naming the font, kept to hand for diagnostics
`Subtype`	Font dictionary subtype: `Type0`, `Type1`, `TrueType`, `CIDFontType2` and friends
`Strategies`	Set of fallback strategies filled in successfully
`ToUnicodeMap`	Parsed `/ToUnicode` CMap with bfchar and bfrange entries, carrying the highest priority
`EncodingMap`	Parsed `/Encoding` stream or named CMap
`PredefinedEncoding`	Predefined encoding name such as `WinAnsiEncoding`
`CIDToGIDIdentity`	True when the CIDToGIDMap is Identity and no explicit table is required
`CIDToGIDs`	Binary CIDToGIDMap stream expanded to one Word per CID
`CIDToUnicode`	CID to Unicode table from the cid2code.txt fallback
`GlyphNameUnicode`	256-entry glyph name to Unicode table used by `/Differences` recovery
`GIDToUnicode`	Embedded cmap reversed from glyph ID to Unicode
`Widths`	Simple-font `/Widths` advances in 1/1000 em, indexed by code minus `FirstChar`
`FirstChar`	First supported char code of the `Widths` array
`LastChar`	Last supported char code of the `Widths` array
`CIDWidths`	CID width ranges from the CIDFont `/W` array
`CIDDefaultWidth`	Default CID advance from `/DW`
`CIDVertWidths`	Vertical `/W2` metrics stored as [w1y v1x v1y] triples per CID or range
`CIDVertDefaultAdvance`	Default vertical displacement from `/DW2` w1y, -1000 by default
`CIDVertDefaultOriginY`	Default vertical origin from `/DW2` v1y, 880 by default
`VerticalWriting`	True when WMode 1 metrics gate the resolver's vertical branch
`Ascent`	Font ascent read from the font descriptor metrics
`Descent`	Font descent read from the font descriptor metrics
`HasVerticalMetrics`	True when vertical metrics were found for the font
`CodeUnitBytes`	Bytes per char code, answered to the content interpreter on the font's behalf
`OK`	True when at least one decode strategy can be used

Usage notes

Build with HPDFBuildFontDecoder; the plain record keeps a page worth of fonts cheap, with no heap allocation of its own
HPDFDecodeCharCode walks the strategies in priority order and returns 0 on a miss; missing streams degrade silently to the next strategy
Call HPDFCloneFontDecoder when a decoder must outlive the cache that produced it, because the dynamic arrays are shared by reference

THPDFFontDecoder Record

Declaration

Unit

Fields

Usage notes

Related APIs