SynEdit: How to do background highlighting of multiple text regions given start and stop positions?

7
votes

Using: Delphi XE2, Windows VCL forms application, 32-bit

I'm using the SynEdit control to display text. I'm already using the TSynHTMLSyn syntax highlighter with the control to properly highlight HTML and JS code.

I'm also doing a diff on this text (using Angus Johnson's TDiff) with another version of the text to find: deletions, additions and changes. I need to highlight each of these type of changes with a different color ie RED for deletion, BLUE for additions, and GREEN for changes.

My questions:

  1. Is it possible to implement?
  2. If yes, then how?

TIA.

1
delphisynedit
I am not really a SynEdit user but if nothing else helped, I'd try something like E.SelStart := x; E.SelEnd := y; E.SelectedColor := c; (looking at the class's member set here and here). – Andriy M
This works but I need: 1) Multiple selections to be highlighted 2) Even if the user clicks in the control to select some other text, the text that was highlighted earlier should remain highlighted. – Steve F
Have you checked the fork of TSynEdit that is used by the Lazarus IDE? I think it can handle multiple highlighted blocks that persists when editing. – LU RD
See if you can make something out of this: SynEdit Highlighter. – LU RD

1 Answers

1
votes

Try to use TSynEdit.onSpecialLineColors event, e.g.

procedure TfmRunScript.EditorSpecialLineColors(Sender: TObject;
  Line: Integer; var Special: Boolean; var FG, BG: TColor);
begin
 if Line = ErrorLine then
  begin
   Special := True;
   BG := clMaroon;
   FG := clWhite;
  end;
end;