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Fix Format 4 character map glyph lookup #2

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Fix Format 4 character map glyph lookup #2

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50 changes: 31 additions & 19 deletions Source/PT_CharacterMap.pas
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Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,7 @@ TPascalTypeFormat4CharacterMap = class(TCustomPascalTypeCharacterMap)

TPascalTypeFormat6CharacterMap = class(TCustomPascalTypeCharacterMap)
private
FLanguage: Word; // Please see �Note on the language field in 'cmap' subtables� in this document.
FLanguage: Word; // Please see “Note on the language field in 'cmap' subtables“ in this document.
FFirstCode: Word; // First character code of subrange.
FGlyphIdArray: array of Word; // Array of glyph index values for character codes in the range.
function GetEntryCount: Word;
Expand All @@ -120,7 +120,7 @@ TPascalTypeFormat6CharacterMap = class(TCustomPascalTypeCharacterMap)

TPascalTypeFormat12CharacterMap = class(TCustomPascalTypeCharacterMap)
private
FLanguage: Cardinal; // Please see �Note on the language field in 'cmap' subtables� in this document.
FLanguage: Cardinal; // Please see “Note on the language field in 'cmap' subtables“ in this document.
FCoverageArray: array of TCharMapSegmentedCoverageRecord;
protected
class function GetFormat: Word; override;
Expand Down Expand Up @@ -298,20 +298,30 @@ procedure TPascalTypeFormat4CharacterMap.AssignTo(Dest: TPersistent);
inherited;
end;

function TPascalTypeFormat4CharacterMap.CharacterToGlyph(CharacterIndex: Integer): Integer;

function TPascalTypeFormat4CharacterMap.CharacterToGlyph
(CharacterIndex: Integer): Integer;
var
SegmentIndex: Integer;
SegmentIndex : Integer;
OffsetIndex : Integer;
SegCount : Integer;
begin
SegmentIndex := 0;
while (SegmentIndex < Length(FEndCount)) do
if (CharacterIndex <= FEndCount[SegmentIndex]) then
Break
else
Inc(SegmentIndex);
SegCount := Length(FEndCount);

// find matching segment
while (SegmentIndex < SegCount) and
(CharacterIndex > FEndCount[SegmentIndex]) do
Inc(SegmentIndex);

if not(CharacterIndex >= FStartCount[SegmentIndex]) then
if SegmentIndex >= SegCount then
begin
Result := 0;
Exit;
end;

if CharacterIndex < FStartCount[SegmentIndex] then
begin
// missing glyph
Result := 0;
Exit;
end;
Expand All @@ -320,21 +330,23 @@ function TPascalTypeFormat4CharacterMap.CharacterToGlyph(CharacterIndex: Integer
Result := (FIdDelta[SegmentIndex] + CharacterIndex) mod (1 shl 16)
else
begin
Result := FIdRangeOffset[SegmentIndex] +
(CharacterIndex - FStartCount[SegmentIndex]);
OffsetIndex := (FIdRangeOffset[SegmentIndex] div 2) +
(CharacterIndex - FStartCount[SegmentIndex]) -
(SegCount - SegmentIndex);

// modulo operation
Result := Result mod (1 shl 16);
if (OffsetIndex >= 0) and (OffsetIndex < Length(FGlyphIdArray)) then
Result := FGlyphIdArray[OffsetIndex]
else
Result := 0;

// check for missing character and add offset eventually
if Result = 0 then
Result := FIdDelta[SegmentIndex] mod (1 shl 16)
if Result <> 0 then
Result := (Result + FIdDelta[SegmentIndex]) mod (1 shl 16);
end;

Result := Result mod (1 shl 16);

end;


procedure TPascalTypeFormat4CharacterMap.LoadFromStream(Stream: TStream);
var
StartPos: Int64;
Expand Down