How would you render soft returns in a Richedit control?

Question

In an application that displays a richedit control I would like to be able to visually distinguish soft returns (produced with SHIFT ENTER) from hard returns (produced with ENTER).

I already use the JVCL richedit and don't want to switch at that point.

How would you proceed to do that?

Microsoft Word may be an inspiration source, they display a ↵ sign for soft returns and a ¶ sign for hard returns at the end of each line.

I am just looking for hints, good ideas how you would tackle this project. I am not asking anybody to do my work, of course. :-)

Answer 1

Although not a direct answer to your question, there is a possible solution to the problem you mentioned of needing to use both Richedit and Syntax highlighting in one control and that is the use of SynEdit.

SynEdit include some non-visual components that allow exporting syntax formatted text, one of those components is TSynExporterRTF.

Suppose you have a section of code which is in plain text inside your richedit and you want to syntax highlight that portion, you could select and copy that text to a TSynEdit and then export it to a TSynExporterRTF which will now contain syntax formatted text (assuming a highlighter has been defined correctly). Then you can simply write the data to a TMemoryStream and replace the selected richedit text with the now syntax formatted code.

To do this you can try something like this:

procedure SyntaxFormatRichEditText(RichEdit: TRichEdit; SynHighlighter: TSynCustomHighlighter);
var
  SynEdit: TSynEdit;
  SynExporterRTF: TSynExporterRTF;
  MS: TMemoryStream;
begin
  SynEdit := TSynEdit.Create(nil);
  try
    SynEdit.Highlighter := SynHighlighter;
    SynEdit.Lines.Text := RichEdit.SelText;

    SynExporterRTF := TSynExporterRTF.Create(nil);
    try
      SynExporterRTF.Highlighter := SynHighlighter;

      MS := TMemoryStream.Create;
      try
        SynExporterRTF.ExportAll(SynEdit.Lines);
        SynExporterRTF.SaveToStream(MS);
        MS.Seek(0, soBeginning);
        RichEdit.SetSelTextBuf(MS.Memory);
        RichEdit.SetFocus;
      finally
        MS.Free;
      end;
    finally
      SynExporterRTF.Free;
    end;
  finally
    SynEdit.Free;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  SyntaxFormatRichEditText(RichEdit1, SynPasSyn1);
end;

If anything though, as others have suggested the requirements you need are likely out of scope as to what the Richedit controls can offer.