Или используй примерно такой код:

procedure TMessage_Table.rxgrHeaderDrawDataCell(Sender: TObject;
const Rect: TRect; Field: TField; State: TGridDrawState);
begin
if Field.FieldName = 'IndInputSign' then
begin
if rxquHeader.FieldByName('InputSign').AsInteger = 1 then
rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndInput.Font
else
rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndOutput.Font ;
end
else
begin
if Field.FieldName = 'IndPostingSign' then
begin
if rxquHeader.FieldByName('inputSign').AsInteger = 1 then
begin
case rxquHeader.FieldByName('postingSign').AsInteger of
1: rxgrHeader.Canvas.Font := SPM_Legend_Form.Panel2.Font ;
2: rxgrHeader.Canvas.Font := SPM_Legend_Form.Panel3.Font ;
3: rxgrHeader.Canvas.Font := SPM_Legend_Form.Panel4.Font ;
4: rxgrHeader.Canvas.Font := SPM_Legend_Form.Panel5.Font ;
end ;
end
else
begin
case rxquHeader.FieldByName('postingSign').AsInteger of
-1: rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndPosting.Font ;
0 : rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndPosting2.Font ;
else
rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndPosting1.Font ;
end ;
end ;
end
else
begin
if Field.FieldName = 'IndStatus' then
begin
case rxquHeader.FieldByName('Status').AsInteger of
0 : rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndStatus.Font ;
1 : rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndStatus1.Font ;
2 : rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndStatus2.Font ;
3 : rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndStatus3.Font ;
4 : rxgrHeader.Canvas.Font := SPM_Legend_Form.paIndStatus4.Font ;
end ;
end
else
begin
// if rxquHeader.FieldByName('sendDepNumber').AsInteger <> AppForm.fDepRefID then
// rxgrHeader.Canvas.Brush.Color := clYellow ;
// rxgrHeader.Canvas.Font := rxgrHeader.Font ;
end ;
end ;
end ;
rxgrHeader.DefaultDrawDataCell(Rect, Field, State);
end;