判断是否有TrueType字体
function IsTrueTypeAvailable : bool;
var
{$IFDEF WIN32}
rs : TRasterizerStatus;
{$ELSE}
rs : TRasterizer_Status;
{$ENDIF}
begin
result := false;
if not GetRasterizerCaps(rs, sizeof(rs)) then exit;
if rs.WFlags and TT_AVAILABLE <> TT_AVAILABLE then exit;
if rs.WFlags and TT_ENABLED <> TT_ENABLED then exit;
result := true;
end;