Marks Placement when using mouse wheel

[Errol]

Good evening

I use stacked bar charts to represent a geological column. Besides each section (strata) I place a comment using the code below:

Code: Select all

procedure TPBQuickGraph.PlaceComments;
var
  s, i, tmpSize, LIndex, LMarksHeight : integer;
  LComment: string;

begin
  Chart.Draw;
  LIndex := 0; // legend included so need to pick 2, 4, etc (0 = legend)
  for s := 1 to fIntervalQueryCollection.SeriesListB.Count - 1 do
    if (s mod 2 = LIndex) then // every second series in SeriesListB
      with TUnitBarSeries(fIntervalQueryCollection.SeriesListB.Objects[s]) do
      begin
        fIntervalQueryCollection.IntervalQuery.First;
        for i := 0 to TUnitBarSeries(fIntervalQueryCollection.SeriesListB.Objects[s]).Count - 1 do
        begin
          LComment := fIntervalQueryCollection.IntervalQuery.FieldByName('Strata Comment').AsString;
          with Marks.Positions[i] do
          begin
            if (Labels[i] <> '') then
            begin
              Custom := true;
              LeftTop.X := CalcXPos(0) + fBarWidth + fCommentStart;
              tmpSize := CalcYSizeValue(YValue[i]);
              LMarksHeight := Marks.Height;
              LeftTop.Y := CalcYPos(i) - (tmpSize div 2) - (LMarksHeight div 2);
            end
            else
              Marks.Item[i].Text.Text := '';
          end;
          fIntervalQueryCollection.IntervalQuery.Next;
        end;
      end;
end;

This places the comments correctly when first displaying the graph and when called after the OnZoom, OnUndoZoom and OnScroll events. However, calling PlaceComments in the OnMouseWheel event misplaces the marks up or down as shown in the following figures.

The attachment Comment_Location.png is no longer available

The attachment Comment_Location_Down.png is no longer available

Correct position of comments

Comment_Location.png (2.51 KiB) Viewed 13278 times

I would be grateful if you can suggest how I might fix this.
Best regards
Errol

[Yeray]

Hello,

Maybe you need to force another repaint (Chart1.Draw) at the end of this method.
I can't see all the images, could you please edit your opening post or reply adding them?

[Errol]

Good afternoon
Thanks for your suggestions. I have tried calling Chart.Draw at various places - in PlaceComments and in OnMouseWheel, to no avail.
I have attached the images again. I hope they get through this time.

The attachment Comment_Correct_Location.png is no longer available

The attachment Comment_Location_MouseWheelDown.png is no longer available

Correct comment location

Comment_Correct_Location.png (4 KiB) Viewed 13270 times

[Errol]

I seem unable to attach the three images so I have attached images 2 and 3 here.

The attachment Comment_Location_MouseWheelDown.png is no longer available

Comment location after mouse wheel down

Comment_Location_MouseWheelDown.png (4.39 KiB) Viewed 13270 times

[Errol]

And here is the final image. Each time, Preview shows the three images correctly, but when I submit the post, the attachments vanish

[Yeray]

Hello Errol,

I'm sorry for the problems attaching images. There seems to be a bug in phpbb 3.2.2 (reference here). I've applied the fix and it seems to be working now.

Regarding the problem with the marks, note the OnMouseWheel event is fired before applying the axis scroll. That's why your PlaceComments method doesn't calculate the positions properly. You can set a flag at OnMouseWheel and call PlaceComments at OnAfterDraw event when that flag is set. Here a simple example:

testMarks.zip

(83.23 KiB) Downloaded 845 times

[Errol]

Good evening
Thank you for your assistance here. I have implemented your suggestions and it works fine now. Obvious really, once one knows how to do it, but I find the TeeChart events a bit daunting at times.
Best regards
Errol