Drawing special symbols on Candlestick chart

[Rangarajan]

I am displaying a Candle series in a Chart window. Based on some algorithm, I would like to display some special symbol (say, up triangle, down triangle, arrow, etc.) on some elements of the series. The symbol may have to be displayed either above the candlestick or below it. How can I do this? Obviously, because the symbol is logically "tied" to certain candlesticks, they should not vanish when I zoom or scroll the chart.

- Rangarajan

[Yeray]

Hello Rangarajan,

You could use a TPointSeries and use OnGetPointerStyle to modify its pointers as you wish. Ie:

Code: Select all

procedure TForm1.FormCreate(Sender: TObject);
begin
  //...
  with TPointSeries(Chart1.AddSeries(TPointSeries)) do
  begin
    Pointer.Size:=6;

    AddXY(candleSeries.XValue[2], candleSeries.HighValues[2]);
    AddXY(candleSeries.XValue[6], candleSeries.LowValues[6]);

    OnGetPointerStyle:=SeriesGetPointerStyle;
  end;
end;

function TForm1.SeriesGetPointerStyle(Sender: TChartSeries;
  ValueIndex: Integer): TSeriesPointerStyle;
begin
  case ValueIndex of
    0: Result:=psTriangle;
    1: Result:=psDownTriangle;
  end;
end;

Project1_2022-01-26_12-08-04.png (13.17 KiB) Viewed 8989 times

[Rangarajan]

Looks good, thanks. Let me try this.

- Rangarajan

[Rangarajan]

Thanks again. It works as expected.

1) How would I handle the case where I need to draw vertical lines (in different colours) on candlestick chart, instead of symbols? The vertical lines need to span the entire height of the chart window without any specific Y values.
2) Is it possible to display arbitrary information when moving the mouse over each candlestick element? Or when clicking on a specific element?

- Rangarajan

[Yeray]

Hello Rangarajan,

1) How would I handle the case where I need to draw vertical lines (in different colours) on candlestick chart, instead of symbols? The vertical lines need to span the entire height of the chart window without any specific Y values.

This sounds like the TColorLineTool. Take a look at the ColorLine example in the Features Demo shipped with the installation.

Tee9new_2022-02-03_12-58-42.png (250.87 KiB) Viewed 8907 times

2) Is it possible to display arbitrary information when moving the mouse over each candlestick element? Or when clicking on a specific element?

Have you seen the MarksTipTool?

Tee9new_2022-02-03_13-01-18.png (278.68 KiB) Viewed 8907 times

[Rangarajan]

Super! Thanks.

- Rangarajan