Trim filename but keep file extension

Question

Does anyone know how to trim a string/filename but keep the file extension?

For example:

I would like Picture1.jpg to become Pic.jpg .

I've been playing around with the StrUtils unit without being able to work out a solution. LeftStr was the first thing that came to mind.

Answer 1

Split the name into stem and extension. Shorten the stem. Then re-combine. Like this:

function ReduceFileName(const FileName: string; const MaxStemLength: Integer): string;
var
  Ext: string;
  StemLength: Integer;
begin
  Assert(MaxStemLength > 0);
  Ext := ExtractFileExt(FileName);
  StemLength := Length(FileName) - Length(Ext);
  if StemLength <= MaxStemLength then begin
    Result := FileName;
    exit;
  end;
  Result := Copy(FileName, 1, MaxStemLength) + Ext;
end;