Using the new OnShowHint event

[pyscripter]

One of the SynEdit enhancements is the addition of the OnShowHint event (#28). This can be very useful for showing context-sensitive hints. PyScripter for instance uses this event to display code hints, debugger hints, syntax errors, etc.

Here is an example event handler that demonstrates how to use this event. The code is meant to show the hint "Spelling error" when the mouse rests on top of a spelling error. You can adapt the code to show a hint depending on the word at cursor, the highlighter attribute etc. The code sample also shows how to work with Indicators (#29).

procedure TEditorForm.SynEditorShowHint(var HintStr: string; var CanShow:
  Boolean; var HintInfo: Controls.THintInfo);
var
  Indicator: TSynIndicator;
begin
  var Editor := HintInfo.HintControl as TCustomSynEdit;
  var DC := Editor.PixelsToNearestRowColumn(HintInfo.CursorPos.X, HintInfo.CursorPos.Y);
  var BC := Editor.DisplayToBufferPos(DC);

  if Editor.Indicators.IndicatorAtPos(BC, TSynSpellCheck.SpellErrorIndicatorId, Indicator) then
  begin
    CanSHow := True;
    HintStr := 'Spelling Error';

    var BC1 := BufferCoord(Indicator.CharStart, BC.Line);
    var BC2 := BufferCoord(Indicator.CharEnd, BC.Line);

    var P1 := Editor.RowColumnToPixels(Editor.BufferToDisplayPos(BC1));
    var P2 := Editor.RowColumnToPixels(Editor.BufferToDisplayPos(BC2));

    Inc(P2.Y, Editor.LineHeight);

    // Setting HintInfo.CursorRect is important.  Otherwise, no other hint
    // will be shown unless the mouse leaves and reenters the control
    HintInfo.CursorRect := TRect.Create(P1,P2);
    HintInfo.HintPos := Editor.ClientToScreen(Point(P1.X, P2.Y));
  end
  else
    CanShow := False;
end;