Skia's TTextLayout text engine does not recognize the variant selectors (U+E01E0..U+E01EF surrogate pairs) for the ToneOZ font, resulting in the loss of polyphonic phonetic symbols.

[jonahzheng]

skia4delphi/skia4delphi#440

[Zeus64]

Can you try without using Skia (you can use the ALFmxControlsDemo, replace the sample font in it by the ToneOZ)

[jonahzheng]

yes, but I have to use Skia in order to dynamically register the font.

  Application.Initialize;

{$IFDEF MSWINDOWS}
  { Register ToneOZ font directly with Skia from the TTF file so Skia's text
    shaper has full access to the font's OpenType GSUB tables (required for
    polyphonic variation selector / IVS support). System font installation
    alone is not sufficient for Skia. }
  FontFile := TPath.Combine(ExtractFilePath(ParamStr(0)), 'ToneOZ-Pinyin-Kai-Traditional.ttf');
  if not FileExists(FontFile) then
    FontFile := TPath.Combine(ExtractFilePath(ParamStr(0)), '..\..\ToneOZ-Pinyin-Kai-Traditional.ttf');
  if FileExists(FontFile) then
    TSkDefaultProviders.RegisterTypeface(FontFile)
  else
    OutputDebugString('ToneOZ font file not found for Skia registration');
{$ENDIF}

{$IF Defined(IOS)}
  FontList := TStringList.Create;
  try
    FontList.Add('ToneOZ-Pinyin-Kai-Traditional=ToneOZ-Pinyin-Kai-Traditional.ttf');
    for I := 0 to FontList.Count - 1 do
    begin
      FontFile := TPath.GetDocumentsPath + PathDelim + FontList.ValueFromIndex[I];
      if FileExists(FontFile) then
      begin
        THtCanvasIOS.RegisterCustomFont(FontList.Names[I], FontFile);
        TSkDefaultProviders.RegisterTypeface(FontFile);
      end;
    end;
  finally
    FontList.Free;
  end;
{$ENDIF}

{$IF Defined(ANDROID)}
  FontFile := TPath.GetDocumentsPath + PathDelim + 'ToneOZ-Pinyin-Kai-Traditional.ttf';
  if FileExists(FontFile) then
    TSkDefaultProviders.RegisterTypeface(FontFile);
{$ENDIF}

{$IF Defined(MACOS) and not Defined(IOS)}
  if TPlatformServices.Current.SupportsPlatformService(IFMXFontManagerService, FontMgrSvc) then
  begin
    FontFile := TPath.Combine(TPath.GetHomePath, 'ToneOZ-Pinyin-Kai-Traditional.ttf');
    if FileExists(FontFile) then
      FontMgrSvc.AddCustomFontFromFile(FontFile);
  end;
{$ENDIF}