对于项目，我需要读取TrueType字体文件（.ttf）中的名称。我写了一个代码来实现这一点，从c ++示例中得到启发。这是代码：
TWByteArray = array of Byte;
TWAnsiCharArray = array of AnsiChar;
...
//---------------------------------------------------------------------------
class function TWStringHelper.ByteToStr(const bytes: TWByteArray): string;
begin
SetLength(Result, Length(bytes));
if Length(Result) > 0 then
Move(bytes[0], Result[1], Length(bytes));
end;
//---------------------------------------------------------------------------
class function TWStringHelper.UniStrToByte(const str: UnicodeString): TWByteArray;
begin
SetLength(Result, Length(str) * SizeOf(WideChar));
if (Length(Result) > 0) then
Move(str[1], Result[0], Length(Result));
end;
//---------------------------------------------------------------------------
class function TWStringHelper.BytesToUniStr(const bytes: TWByteArray): UnicodeString;
begin
SetLength(Result, Length(bytes) div SizeOf(WideChar));
if Length(Result) > 0 then
Move(bytes[0], Result[1], Length(bytes));
end;
//---------------------------------------------------------------------------
...
//---------------------------------------------------------------------------
class function TWControlFont.SwapWord(value: Word): Word;
begin
Result := MakeWord(HiByte(value), LoByte(value));
end;
//---------------------------------------------------------------------------
class function TWControlFont.SwapLong(value: LongInt): LongInt;
begin
Result := MakeLong(SwapWord(HiWord(value)), SwapWord(LoWord(value)));
end;
//---------------------------------------------------------------------------
class function TWControlFont.GetFontNameFromFile(const fileName: UnicodeString): UnicodeString;
var
pFile: TFileStream;
offsetTable: ITTFOffsetTable;
dirTable: ITTFDirectoryTable;
nameHeader: ITTFNameTableHeader;
nameRecord: ITTFNameRecord;
nameBuffer: TWByteArray;//TWAnsiCharArray;
i: USHORT;
found: Boolean;
test2: string;
test3: UnicodeString;
test: Integer;
const name: array [0..3] of Byte = (Ord('n'), Ord('a'), Ord('m'), Ord('e'));
begin
// open font file
pFile := TFileStream.Create(fileName, fmOpenRead);
// succeeded?
if (not Assigned(pFile)) then
Exit;
try
pFile.Seek(0, soFromBeginning);
// read TTF offset table
if (pFile.Read(offsetTable, SizeOf(ITTFOffsetTable)) <> SizeOf(ITTFOffsetTable)) then
Exit;
offsetTable.m_NumOfTables := SwapWord(offsetTable.m_NumOfTables);
offsetTable.m_MajorVersion := SwapWord(offsetTable.m_MajorVersion);
offsetTable.m_MinorVersion := SwapWord(offsetTable.m_MinorVersion);
// is truetype font and version is 1.0?
if ((offsetTable.m_MajorVersion <> 1) or (offsetTable.m_MinorVersion <> 0)) then
Exit;
found := False;
// iterate through file tables
if (offsetTable.m_NumOfTables > 0) then
for i := 0 to offsetTable.m_NumOfTables - 1 do
begin
// read table
if (pFile.Read(dirTable, SizeOf(ITTFDirectoryTable)) <> SizeOf(ITTFDirectoryTable)) then
Exit;
// found name table?
if (CompareMem(@dirTable.m_Tag, @name, 4) = True) then
begin
found := True;
dirTable.m_Length := SwapLong(dirTable.m_Length);
dirTable.m_Offset := SwapLong(dirTable.m_Offset);
break;
end;
end;
// found name table?
if (not found) then
Exit;
// seek to name location
pFile.Position := dirTable.m_Offset;
// read name table header
if (pFile.Read(nameHeader, SizeOf(ITTFNameTableHeader)) <> SizeOf(ITTFNameTableHeader)) then
Exit;
nameHeader.m_NRCount := SwapWord(nameHeader.m_NRCount);
nameHeader.m_StorageOffset := SwapWord(nameHeader.m_StorageOffset);
// iterate through name records
if (nameHeader.m_NRCount > 0) then
for i := 0 to nameHeader.m_NRCount - 1 do
begin
// read name record
if (pFile.Read(nameRecord, SizeOf(ITTFNameRecord)) <> SizeOf(ITTFNameRecord)) then
Exit;
nameRecord.m_NameID := SwapWord(nameRecord.m_NameID);
// found font name?
if (nameRecord.m_NameID = 1) then
begin
// get font name length and offset
nameRecord.m_StringLength := SwapWord(nameRecord.m_StringLength);
nameRecord.m_StringOffset := SwapWord(nameRecord.m_StringOffset);
if (nameRecord.m_StringLength = 0) then
continue;
// calculate and seek to font name offset
pFile.Position := dirTable.m_Offset + nameRecord.m_StringOffset + nameHeader.m_StorageOffset;
try
SetLength(nameBuffer, nameRecord.m_StringLength + 1);
//REM FillChar(nameBuffer[0], nameRecord.m_StringLength + 1, $0);
// read font name from file
if (pFile.Read(nameBuffer[0], nameRecord.m_StringLength)
<> nameRecord.m_StringLength)
then
Exit;
nameBuffer[nameRecord.m_StringLength] := $0;
//OutputDebugString(PChar(nameBuffer));
//TWMemoryHelper.SwapBytes(nameBuffer[0], nameRecord.m_StringLength);
//OutputDebugString(PChar(nameBuffer));
//test := StringElementSize(RawByteString(@nameBuffer[0]));
//Result := TWStringHelper.BytesToUniStr(nameBuffer);
//Result := UnicodeString(AnsiString(TWStringHelper.ByteToStr(nameBuffer)));
//REM Result := UnicodeString(nameBuffer);
test2 := TWStringHelper.ByteToStr(nameBuffer);
OutputDebugStringA(PAnsiChar(test2));
test3 := UnicodeString(PAnsiChar(test2));
OutputDebugStringW(PWideChar(test3));
Result := test3;
OutputDebugStringW(PWideChar(test3));
finally
SetLength(nameBuffer, 0);
end;
break;
end;
end;
finally
pFile.Free;
end;
end;
//---------------------------------------------------------------------------
此代码适用于GetFontNameFromFile（）函数的最后一部分。事情开始变得复杂起来。实际上，我无法以正确的方式将nameBuffer字节数组转换为字符串。
我遇到的第一个问题是nameBuffer可能是一个简单的ASCII字符串，或UTF16字符串，依赖于文件（我尝试使用FireFox中提供的emoji.ttf，它返回一个ASCII字符串，以及来自的Tahoma.ttf）我的Win安装，返回UTF16字符串）。我需要一种方法来确定，并且我不知道VCL中是否有函数或类来执行此操作。
第二个问题是转换本身。上面的代码或多或少有效，但我觉得这不是一个正确的解决方案。当我尝试直接从nameBuffer转换为UnicodeString时，我遇到了一些奇怪的崩溃。如果我尝试将nameBuffer转换为AnsiString，转换似乎成功，但是像UnicodeString（AnsiString（nameBuffer））这样的转换失败。
代码似乎充满了内存问题。由于我是Delphi的新手，我对内存使用情况不太满意。例如，我怀疑在激活
时字节数组有几个问题FillChar(nameBuffer[0], nameRecord.m_StringLength + 1, $0);
线。
所以任何人都可以分析这些代码并指出我做错了什么？
提前致谢， 此致