Candle chart export

120 bars from 2026-01-05 to 2026-06-19
  ok: four panes: Price, Volume, Momentum, MACD
  ok: SMA(20) starts at bar 20 with the mean of the closes
  ok: Bollinger bands enclose the SMA
  ok: RSI(14) starts at bar 15 and stays within 0..100
  last close 119.44, SMA(20) 117.61, RSI(14) 61.3
  ok: CSV round trip
  ok: candles.png written
  ok: the view shows the last 40 bars
  ok: the SVG names the studies in the pane headers
  ok: candles.svg written
Files written to C:\...\CandleChartExport

program CandleChartExport;

{$APPTYPE CONSOLE}

// Atlas Fin quick start: build OHLCV bars in code, add studies, verify the
// indicator values and export the chart to PNG and SVG without a window.

uses
  System.SysUtils, System.Classes, System.Math, System.DateUtils, System.IOUtils,
  Atlas.FinData, Atlas.FinIndicators, Atlas.FinChart;

procedure Check(Condition: Boolean; const Message: string);
begin
  if not Condition then raise Exception.Create('Check failed: ' + Message);
  Writeln('  ok: ', Message);
end;

// Deterministic weekday bars: the same prices on every run and platform.
procedure FillBars(Data: TAtlasBarSeries; Count: Integer);
var
  Seed: Cardinal;
  Day: TDateTime;
  Price, Open, Close, High, Low: Double;
  I: Integer;
  function Next: Double;
  begin
    Seed := Cardinal((UInt64(Seed) * 1664525 + 1013904223) and $FFFFFFFF);
    Result := (Seed shr 8) / 16777216;
  end;
begin
  Seed := 2026;
  Day := EncodeDate(2026, 1, 5); // a Monday
  Price := 100;
  Data.BeginUpdate;
  try
    Data.Clear;
    I := 0;
    while I < Count do
    begin
      if DayOfTheWeek(Day) <= 5 then
      begin
        Open := Price * (1 + (Next - 0.5) * 0.01);
        Close := Open * (1 + (Next - 0.48) * 0.03);
        High := Max(Open, Close) * (1 + Next * 0.01);
        Low := Min(Open, Close) * (1 - Next * 0.01);
        Data.Add(Day, Open, High, Low, Close, Round(500000 + Next * 500000));
        Price := Close;
        Inc(I);
      end;
      Day := Day + 1;
    end;
  finally
    Data.EndUpdate;
  end;
end;

var
  Chart: TAtlasFinChart;
  Loaded: TAtlasBarSeries;
  Sma, Rsi: TArray<Double>;
  Bands: TAtlasBands;
  Expected: Double;
  I, Last: Integer;
  Svg: string;
begin
  try
    Chart := TAtlasFinChart.Create(nil);
    try
      FillBars(Chart.Data, 120);
      Last := Chart.Data.Count - 1;
      Writeln(Format('%d bars from %s to %s', [Chart.Data.Count,
        FormatDateTime('yyyy-mm-dd', Chart.Data[0].Time), FormatDateTime('yyyy-mm-dd', Chart.Data[Last].Time)]));

      // Price pane with candles and SMA(20), a volume pane and an RSI(14) pane.
      Chart.SetupDefault;
      Chart.Panes[0].Studies.Add(skBollinger, 20);
      Chart.Panes.Add('MACD', 100).Studies.Add(skMACD);
      Check(Chart.Panes.Count = 4, 'four panes: Price, Volume, Momentum, MACD');

      // The SMA(20) study line equals the mean of the closes it covers.
      Sma := Chart.Panes[0].Studies[1].Lines(Chart.Data)[0];
      Expected := 0;
      for I := 0 to 19 do Expected := Expected + Chart.Data[I].Close / 20;
      Check(IsNan(Sma[18]) and SameValue(Sma[19], Expected, 1E-9), 'SMA(20) starts at bar 20 with the mean of the closes');

      // The same indicators are available without a chart.
      Bands := TAtlasIndicators.Bollinger(Chart.Data.Closes, 20, 2);
      Check((Bands.Upper[Last] > Bands.Middle[Last]) and (Bands.Lower[Last] < Bands.Middle[Last]) and
        SameValue(Bands.Middle[Last], Sma[Last], 1E-9), 'Bollinger bands enclose the SMA');
      Rsi := TAtlasIndicators.RSI(Chart.Data.Closes, 14);
      Check(IsNan(Rsi[13]) and (Rsi[14] >= 0) and (Rsi[14] <= 100), 'RSI(14) starts at bar 15 and stays within 0..100');
      Writeln(Format('  last close %.2f, SMA(20) %.2f, RSI(14) %.1f', [Chart.Data[Last].Close, Sma[Last], Rsi[Last]]));

      // CSV out and back in. ToCSV writes 15 significant digits, so computed
      // prices come back equal to within rounding, not bit for bit.
      Loaded := TAtlasBarSeries.Create;
      try
        Loaded.LoadCSV(Chart.Data.ToCSV);
        Check((Loaded.Count = Chart.Data.Count) and (Loaded[Last].Time = Chart.Data[Last].Time) and
          SameValue(Loaded[Last].Close, Chart.Data[Last].Close, 1E-9), 'CSV round trip');
      finally
        Loaded.Free;
      end;

      // Export: the chart needs no parent or window for this.
      Chart.SaveToFile('candles.png', 900, 600);
      Check(TFile.Exists('candles.png') and (TFile.GetSize('candles.png') > 5000), 'candles.png written');
      Chart.ZoomTo(Chart.Data.Count - 40, 40);
      Check((Chart.FirstBar = 80) and (Chart.VisibleBars = 40), 'the view shows the last 40 bars');
      Chart.SaveToFile('candles-zoom.png', 900, 600);
      Svg := Chart.ToSVG(900, 600);
      Check((Pos('<svg', Svg) > 0) and (Pos('SMA(20)', Svg) > 0) and (Pos('MACD(12, 26, 9)', Svg) > 0),
        'the SVG names the studies in the pane headers');
      Chart.SaveToFile('candles.svg', 900, 600);
      Check(TFile.Exists('candles.svg') and (TFile.GetSize('candles.svg') > 2000), 'candles.svg written');
      Writeln('Files written to ', GetCurrentDir);
    finally
      Chart.Free;
    end;
  except
    on E: Exception do
    begin
      Writeln(E.ClassName, ': ', E.Message);
      ExitCode := 1;
    end;
  end;
end.