Chart data logic separation

AuraTrader/AuraTrader.dpr

@@ -12,7 +12,8 @@ uses
     DynamicFMXControl in 'DynamicFMXControl.pas',
     FirstStrategy in 'FirstStrategy.pas',
     Myc.Fmx.Chart in 'Myc.Fmx.Chart.pas',
-    Myc.Trade.DataArray in '..\Src\Myc.Trade.DataArray.pas';
+    Myc.Trade.DataArray in '..\Src\Myc.Trade.DataArray.pas',
+    Myc.FMX.Chart.Series in '..\Src\Myc.FMX.Chart.Series.pas';
 
 {$R *.res}
 

AuraTrader/AuraTrader.dproj

@@ -141,6 +141,7 @@
         <DCCReference Include="FirstStrategy.pas"/>
         <DCCReference Include="Myc.Fmx.Chart.pas"/>
         <DCCReference Include="..\Src\Myc.Trade.DataArray.pas"/>
+        <DCCReference Include="..\Src\Myc.FMX.Chart.Series.pas"/>
         <BuildConfiguration Include="Base">
             <Key>Base</Key>
         </BuildConfiguration>

AuraTrader/FirstStrategy.pas

@@ -12,25 +12,6 @@ uses
 type
     TTimeframe = (M1, M5, H1, D);
 
-    IMycConverter<S, T> = interface(IMycProcessor<S>)
-        function GetSender: IMycDataProvider<T>;
-        property Sender: IMycDataProvider<T> read GetSender;
-    end;
-
-    TMycConverter<S, T> = class abstract(TMycProcessor<S>, IMycConverter<S, T>)
-    private
-        FSender: TMycDataProvider<T>;
-        function GetSender: IMycDataProvider<T>;
-    protected
-        // Broadcasts the given data to all linked processors.
-        procedure Broadcast(const Value: T);
-
-    public
-        constructor Create;
-        destructor Destroy; override;
-        property Sender: IMycDataProvider<T> read GetSender;
-    end;
-
     TMycGenericConverter<S, T> = class(TMycConverter<S, T>)
         type
             TConvertFunc = reference to function(const Value: S): T;
@@ -255,29 +236,4 @@ begin
     Broadcast(FFunc(Value));
 end;
 
-{ TMycConverter<S, T> }
-
-constructor TMycConverter<S, T>.Create;
-begin
-    inherited Create;
-    FSender := TMycDataProvider<T>.Create(Self);
-end;
-
-destructor TMycConverter<S, T>.Destroy;
-begin
-    FSender.Free;
-    inherited Destroy;
-end;
-
-procedure TMycConverter<S, T>.Broadcast(const Value: T);
-begin
-    var cValue := Value;
-    FSender.Notify(function(const Processor: IMycProcessor<T>): Boolean begin Result := Processor.ProcessData(cValue) end);
-end;
-
-function TMycConverter<S, T>.GetSender: IMycDataProvider<T>;
-begin
-    Result := FSender;
-end;
-
 end.

AuraTrader/MainForm.pas

@@ -165,6 +165,10 @@ begin
 
     var OhlcPoint: IMycConverter<TArray<TDataPoint<TAskBidItem>>, TDataPoint<TOhlcItem>> := TTicksToTimeframe.Create(M1);
 
+    var Timestamps: IMycConverter<TDataPoint<TOhlcItem>, TDateTime> :=
+        TMycGenericConverter<TDataPoint<TOhlcItem>, TDateTime>
+            .Create(function(const Ohlc: TDataPoint<TOhlcItem>): TDateTime begin Result := Ohlc.Time; end);
+
     var Ohlc: IMycConverter<TDataPoint<TOhlcItem>, TOhlcItem> :=
         TMycGenericConverter<TDataPoint<TOhlcItem>, TOhlcItem>
             .Create(function(const Ohlc: TDataPoint<TOhlcItem>): TOhlcItem begin Result := Ohlc.Data; end);
@@ -189,13 +193,14 @@ begin
     //
     //    chart.AddDoubleSeries(Hull.Sender);
 
+    chart.SetXAxisSeries<TOhlcItem>(OHLC.Sender);
+    chart.AddOhlcSeries(Ohlc.Sender);
+
     var done := ExecuteStrategy(Symbol, OhlcPoint);
 
     /////
 
     FProcessDone := TState.All([FProcessDone, done]);
-
-    chart.AddOhlcSeries(OhlcPoint.Sender);
 end;
 
 procedure TForm1.TreeViewDblClick(Sender: TObject);

Src/Myc.Fmx.Chart.Series.pas

@@ -0,0 +1,282 @@
+unit Myc.FMX.Chart.Series;
+
+interface
+
+uses
+    System.SysUtils,
+    System.SyncObjs,
+    System.UITypes,
+    FMX.Graphics,
+    Myc.Trade.DataArray,
+    Myc.Trade.DataPoint,
+    Myc.Lazy,
+    Myc.Fmx.Chart;
+
+type
+    TChartSeriesCounter<T> = class(TMycConverter<T, Int64>)
+    private
+        FCount: Int64;
+    protected
+        function ProcessData(const Value: T): Boolean; override;
+    public
+        constructor Create;
+    end;
+
+    TChartSeriesReceiver<T> = class(TMycProcessor<T>)
+    strict private
+        FCurrData: TMycDataArray<T>;
+        FLookback: TWriteable<Int64>;
+    private
+        FData: TWriteable<TMycDataArray<T>>;
+    protected
+        function ProcessData(const Value: T): Boolean; override;
+    public
+        constructor Create(const ALookback: TWriteable<Int64>);
+        property Data: TWriteable<TMycDataArray<T>> read FData;
+    end;
+
+    TChartSeriesProcessor<T> = class(TMycChart.TSeries)
+    strict private
+        FDataSeries: TMycDataArray<T>;
+        FLock: TSpinLock;
+    private
+        FData: TMycDataArray<T>;
+        FDataProvider: IMycDataProvider<T>;
+        FReceiver: TChartSeriesReceiver<T>;
+        FReceiverTag: TTag;
+    protected
+        function GetCount: Int64; override;
+        function GetTotalCount: Int64; override;
+        procedure Update; override;
+
+    public
+        constructor Create(AOwner: TMycChart; const ADataProvider: IMycDataProvider<T>);
+        destructor Destroy; override;
+        property Data: TMycDataArray<T> read FData;
+    end;
+
+    { TChartOhlcSeries }
+    TChartOhlcSeries = class(TChartSeriesProcessor<TOhlcItem>)
+    private
+        FUpColor: TAlphaColor;
+        FDownColor: TAlphaColor;
+    protected
+        function GetValueRange(First, Last: Int64; out MinValue, MaxValue: Double): Boolean; override;
+        procedure Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>); override;
+    public
+        constructor Create(AOwner: TMycChart; const ADataProvider: IMycDataProvider<TOhlcItem>; const AUpColor, ADownColor: TAlphaColor);
+    end;
+
+    { TChartLineSeries }
+    TChartLineSeries = class(TChartSeriesProcessor<Double>)
+    private
+        FLineColor: TAlphaColor;
+        FLineWidth: Single;
+    protected
+        function GetValueRange(First, Last: Int64; out MinValue, MaxValue: Double): Boolean; override;
+        procedure Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>); override;
+    public
+        constructor Create(
+            AOwner: TMycChart;
+            const ADataProvider: IMycDataProvider<Double>;
+            const ALineColor: TAlphaColor;
+            ALineWidth: Single
+        );
+    end;
+
+implementation
+
+uses
+    System.Types,
+    System.Math,
+    FMX.Types;
+
+constructor TChartSeriesCounter<T>.Create;
+begin
+    inherited Create;
+    FCount := 0;
+end;
+
+function TChartSeriesCounter<T>.ProcessData(const Value: T): Boolean;
+begin
+    Result := true;
+    Broadcast(FCount);
+    inc(FCount);
+end;
+
+{ TChartSeriesReceiver<T> }
+
+constructor TChartSeriesReceiver<T>.Create(const ALookback: TWriteable<Int64>);
+begin
+    inherited Create;
+    FLookback := ALookback;
+    FCurrData := TMycDataArray<T>.CreateEmpty;
+    FData := TWriteable<TMycDataArray<T>>.CreateWriteable(FCurrData).Protect;
+end;
+
+function TChartSeriesReceiver<T>.ProcessData(const Value: T): Boolean;
+begin
+    Result := true;
+    FCurrData := FCurrData.Add(Value, FLookback.Value);
+    FData.Value := FCurrData;
+end;
+
+{ TChartSeriesProcessor<T> }
+
+constructor TChartSeriesProcessor<T>.Create(AOwner: TMycChart; const ADataProvider: IMycDataProvider<T>);
+begin
+    inherited Create(AOwner);
+    FLock := TSpinLock.Create(false);
+    FDataSeries := TMycDataArray<T>.CreateEmpty;
+    FData := FDataSeries;
+    FDataProvider := ADataProvider;
+    FReceiver := TChartSeriesReceiver<T>.Create(AOwner.Lookback);
+    FReceiverTag := FDataProvider.Link(FReceiver);
+end;
+
+destructor TChartSeriesProcessor<T>.Destroy;
+begin
+    FDataProvider.Unlink(FReceiverTag);
+    inherited;
+end;
+
+function TChartSeriesProcessor<T>.GetCount: Int64;
+begin
+    Result := FData.Count;
+end;
+
+function TChartSeriesProcessor<T>.GetTotalCount: Int64;
+begin
+    Result := FData.TotalCount;
+end;
+
+procedure TChartSeriesProcessor<T>.Update;
+begin
+    FData := FReceiver.Data.Value;
+end;
+
+{ TChartLineSeries }
+
+constructor TChartLineSeries.Create(
+    AOwner: TMycChart;
+    const ADataProvider: IMycDataProvider<Double>;
+    const ALineColor: TAlphaColor;
+    ALineWidth: Single
+);
+begin
+    inherited Create(AOwner, ADataProvider);
+    FLineColor := ALineColor;
+    FLineWidth := ALineWidth;
+end;
+
+function TChartLineSeries.GetValueRange(First, Last: Int64; out MinValue, MaxValue: Double): Boolean;
+var
+    i: Int64;
+begin
+    MinValue := MaxDouble;
+    MaxValue := -MaxDouble;
+    for i := First to Last do
+    begin
+        var v := Data.Items[i];
+        if not IsNaN(v) then
+        begin
+            MinValue := Min(MinValue, v);
+            MaxValue := Max(MaxValue, v);
+        end;
+    end;
+    Result := (MinValue <> MaxDouble);
+end;
+
+procedure TChartLineSeries.Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>);
+var
+    points: TPathData;
+    i, n: Int64;
+begin
+    points := TPathData.Create;
+    try
+        // Skip warmup data
+        n := First;
+        while (n <= Last) and (IsNaN(Data[n])) do
+            inc(n);
+        if (n > Last) then
+            exit;
+
+        points.MoveTo(TPointF.Create(XForm(n), YForm(Data[n])));
+        for i := n + 1 to Last do
+            if not IsNaN(Data[i]) then
+                points.LineTo(TPointF.Create(XForm(i), YForm(Data[i])));
+
+        Canvas.Stroke.Color := FLineColor;
+        Canvas.Stroke.Thickness := FLineWidth;
+        Canvas.DrawPath(points, 1);
+    finally
+        points.Free;
+    end;
+end;
+
+{ TChartOhlcSeries }
+
+constructor TChartOhlcSeries.Create(
+    AOwner: TMycChart;
+    const ADataProvider: IMycDataProvider<TOhlcItem>;
+    const AUpColor, ADownColor: TAlphaColor
+);
+begin
+    inherited Create(AOwner, ADataProvider);
+    FUpColor := AUpColor;
+    FDownColor := ADownColor;
+end;
+
+function TChartOhlcSeries.GetValueRange(First, Last: Int64; out MinValue, MaxValue: Double): Boolean;
+var
+    i: Int64;
+begin
+    MinValue := MaxDouble;
+    MaxValue := -MaxDouble;
+
+    for i := First to Last do
+    begin
+        var item := Data.Items[i];
+        MinValue := Min(MinValue, item.Low);
+        MaxValue := Max(MaxValue, item.High);
+    end;
+    Result := (MinValue <> MaxDouble);
+end;
+
+procedure TChartOhlcSeries.Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>);
+var
+    i: Int64;
+    x, candleWidth: Single;
+    yOpen, yHigh, yLow, yClose: Single;
+    item: TOhlcItem;
+    isUp: boolean;
+begin
+    candleWidth := Max(2, 0.8 * Abs((XForm(First + 1) - XForm(First))));
+
+    for i := First to Last do
+    begin
+        item := Data.Items[i];
+        x := XForm(i);
+        yOpen := YForm(item.Open);
+        yClose := YForm(item.Close);
+        yHigh := YForm(item.High);
+        yLow := YForm(item.Low);
+        isUp := item.Close >= item.Open;
+
+        if isUp then
+            Canvas.Stroke.Color := FUpColor
+        else
+            Canvas.Stroke.Color := FDownColor;
+        Canvas.Stroke.Thickness := 1.0;
+
+        Canvas.DrawLine(TPointF.Create(x, yHigh), TPointF.Create(x, yLow), 1);
+
+        Canvas.Fill.Color := Canvas.Stroke.Color;
+        if isUp then
+            Canvas.FillRect(TRectF.Create(x - candleWidth / 2, yClose, x + candleWidth / 2, yOpen), 0, 0, AllCorners, 1)
+        else
+            Canvas.FillRect(TRectF.Create(x - candleWidth / 2, yOpen, x + candleWidth / 2, yClose), 0, 0, AllCorners, 1);
+    end;
+end;
+
+end.

Src/Myc.Fmx.Chart.pas

@@ -16,7 +16,6 @@ uses
     FMX.Graphics,
     FMX.Forms,
     Myc.Trade.DataPoint,
-    Myc.Signals,
     Myc.Lazy;
 
 type
@@ -30,10 +29,10 @@ type
             protected
                 function GetCount: Int64; virtual; abstract;
                 function GetTotalCount: Int64; virtual; abstract;
-                function GetValueRange(StartIndex, Count: Int64; out Min, Max: Double): Boolean; virtual; abstract;
                 procedure Update; virtual; abstract;
+                function GetValueRange(StartIndex, Count: Int64; out Min, Max: Double): Boolean; virtual;
                 // The signature is changed to support viewport painting with an index offset
-                procedure Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>); virtual; abstract;
+                procedure Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>); virtual;
                 property MainSeries: TSeries read GetMainSeries;
             public
                 constructor Create(AOwner: TMycChart);
@@ -44,6 +43,7 @@ type
 
     private
         FSeriesList: TList<TSeries>;
+        FXAxisSeries: TSeries;
         FLookback: TWriteable<Int64>;
         FIdleSubscrId: TMessageSubscriptionId;
         FViewStartIndex: Int64;
@@ -64,9 +64,14 @@ type
         constructor Create(AOwner: TComponent); override;
         destructor Destroy; override;
 
-        // Creates an OHLC candlestick/bar series and returns it
+        // Sets the master series that defines the time scale (X-axis). This series is not drawn.
+        // The chart will not render any data until the X-axis series is set.
+        function SetXAxisSeries<T>(const DataProvider: IMycDataProvider<T>): TSeries;
+
+        // Creates an OHLC candlestick/bar series and returns it.
+        // The data provider directly supplies OHLC items, as timestamps are managed by the data series internally.
         function AddOhlcSeries(
-            const DataProvider: IMycDataProvider<TDataPoint<TOhlcItem>>;
+            const DataProvider: IMycDataProvider<TOhlcItem>;
             const AUpColor: TAlphaColor = TAlphaColors.Green;
             const ADownColor: TAlphaColor = TAlphaColors.Red
         ): TSeries;
@@ -85,78 +90,7 @@ implementation
 
 uses
     System.Math,
-    System.SyncObjs,
+    Myc.FMX.Chart.Series;
-    WinApi.Windows,
-    Myc.Trade.DataArray;
-
-type
-    TChartSeriesReceiver<T> = class(TMycProcessor<T>)
-    strict private
-        FCurrData: TMycDataArray<T>;
-        FLookback: TWriteable<Int64>;
-    private
-        FData: TWriteable<TMycDataArray<T>>;
-    protected
-        function ProcessData(const Value: T): Boolean; override;
-    public
-        constructor Create(const ALookback: TWriteable<Int64>);
-        property Data: TWriteable<TMycDataArray<T>> read FData;
-    end;
-
-    TChartSeriesProcessor<T> = class(TMycChart.TSeries)
-    strict private
-        FDataSeries: TMycDataArray<T>;
-        FLock: TSpinLock;
-    private
-        FData: TMycDataArray<T>;
-        FDataProvider: IMycDataProvider<T>;
-        FReceiver: TChartSeriesReceiver<T>;
-        FReceiverTag: TTag;
-    protected
-        function GetCount: Int64; override;
-        function GetTotalCount: Int64; override;
-        procedure Update; override;
-
-    public
-        constructor Create(AOwner: TMycChart; const ADataProvider: IMycDataProvider<T>);
-        destructor Destroy; override;
-        property Data: TMycDataArray<T> read FData;
-    end;
-
-    { TChartOhlcSeries }
-    TChartOhlcSeries = class(TChartSeriesProcessor<TDataPoint<TOhlcItem>>)
-    private
-        FUpColor: TAlphaColor;
-        FDownColor: TAlphaColor;
-    protected
-        function GetValueRange(First, Last: Int64; out MinValue, MaxValue: Double): Boolean; override;
-        procedure Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>); override;
-    public
-        constructor Create(
-            AOwner: TMycChart;
-            const ADataProvider: IMycDataProvider<TDataPoint<TOhlcItem>>;
-            const AUpColor, ADownColor: TAlphaColor
-        );
-    end;
-
-    { TChartLineSeries }
-    TChartLineSeries = class(TChartSeriesProcessor<Double>)
-    private
-        FLineColor: TAlphaColor;
-        FLineWidth: Single;
-    protected
-        function GetValueRange(First, Last: Int64; out MinValue, MaxValue: Double): Boolean; override;
-        procedure Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>); override;
-    public
-        constructor Create(
-            AOwner: TMycChart;
-            const ADataProvider: IMycDataProvider<Double>;
-            const ALineColor: TAlphaColor;
-            ALineWidth: Single
-        );
-    end;
-
-{ TMycChart.TSeries }
 
 constructor TMycChart.TSeries.Create(AOwner: TMycChart);
 begin
@@ -166,9 +100,17 @@ end;
 
 function TMycChart.TSeries.GetMainSeries: TSeries;
 begin
-    Result := nil;
+    Result := Owner.FXAxisSeries;
-    if (Owner.FSeriesList.Count > 0) then
+end;
-        Result := Owner.FSeriesList[0];
+
+function TMycChart.TSeries.GetValueRange(StartIndex, Count: Int64; out Min, Max: Double): Boolean;
+begin
+    Result := false;
+end;
+
+procedure TMycChart.TSeries.Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>);
+begin
+    // nothing
 end;
 
 { TMycChart }
@@ -177,6 +119,7 @@ constructor TMycChart.Create(AOwner: TComponent);
 begin
     inherited Create(AOwner);
     FSeriesList := TObjectList<TSeries>.Create(true);
+    FXAxisSeries := nil;
 
     FLookback := TWriteable<Int64>.CreateWriteable(1000); // Load more data for panning
     FViewStartIndex := 0;
@@ -193,10 +136,24 @@ destructor TMycChart.Destroy;
 begin
     TMessageManager.DefaultManager.Unsubscribe(TIdleMessage, FIdleSubscrId);
 
+    FXAxisSeries.Free;
     FSeriesList.Free;
     inherited;
 end;
 
+function TMycChart.SetXAxisSeries<T>(const DataProvider: IMycDataProvider<T>): TSeries;
+begin
+    // Free the old one if it exists, and create the new master series
+    FXAxisSeries.Free;
+
+    var counter := TChartSeriesCounter<T>.Create;
+
+    DataProvider.Link(counter);
+
+    FXAxisSeries := TChartSeriesProcessor<Int64>.Create(Self, counter.Sender);
+    Result := FXAxisSeries;
+end;
+
 function TMycChart.AddDoubleSeries(
     const DataProvider: IMycDataProvider<Double>;
     const ALineColor: TAlphaColor = TAlphaColors.Cornflowerblue;
@@ -208,7 +165,7 @@ begin
 end;
 
 function TMycChart.AddOhlcSeries(
-    const DataProvider: IMycDataProvider<TDataPoint<TOhlcItem>>;
+    const DataProvider: IMycDataProvider<TOhlcItem>;
     const AUpColor: TAlphaColor = TAlphaColors.Green;
     const ADownColor: TAlphaColor = TAlphaColors.Red
 ): TSeries;
@@ -219,18 +176,26 @@ end;
 
 procedure TMycChart.DoIdle;
 begin
-    if (FSeriesList.Count = 0) then
+    // An X-axis series is required for any operation
+    if not Assigned(FXAxisSeries) then
         exit;
 
-    var prevTotalCount := FSeriesList[0].TotalCount;
+    // First update the master series
+    var prevTotalCount := FXAxisSeries.TotalCount;
+    FXAxisSeries.Update;
+
+    // Check if the master series itself has changed
+    var newTotalCount := FXAxisSeries.TotalCount;
+    var seriesChanged := prevTotalCount <> newTotalCount;
+
+    // Repaint if the last bar is visible, so we display live data
+    var seriesRepaint := FViewStartIndex = 0;
 
-    var seriesRepaint := false;
-    var seriesChanged := false;
     for var series in FSeriesList do
     begin
         var seriesCount := series.TotalCount;
 
-        // Check if this series may need a repaint
+        // Check if this series may need a repaint (if it lags behind the master series and these lags are currently visible)
         if FViewStartIndex <= prevTotalCount - seriesCount then
             seriesRepaint := true;
 
@@ -241,16 +206,15 @@ begin
             seriesChanged := true;
     end;
 
-    // Don't move with live data, if the last bar isn't visible
+    // Don't move chart, if the last bar isn't visible
     if FViewStartIndex > 0 then
     begin
-        var newTotalCount := FSeriesList[0].TotalCount;
         var countDelta := newTotalCount - prevTotalCount;
-
         if countDelta > 0 then
         begin
             // Adjust the start index based on the absolute change in total data points
             FViewStartIndex := FViewStartIndex + countDelta;
+            // Clamp to beginning of dataset
             if FViewStartIndex + FViewCount > newTotalCount then
                 FViewStartIndex := newTotalCount - FViewCount;
         end;
@@ -339,7 +303,8 @@ begin
             exit;
         end;
 
-        if (FSeriesList.Count = 0) or (FViewCount <= 0) then
+        // An X-axis series is required for panning
+        if not Assigned(FXAxisSeries) or (FViewCount <= 0) then
         begin
             exit;
         end;
@@ -352,7 +317,7 @@ begin
         FViewStartIndex := FViewStartIndex + indexDelta;
 
         // Clamp values
-        mainSeries := FSeriesList[0];
+        mainSeries := FXAxisSeries;
         maxIndex := mainSeries.Count - FViewCount;
         if (maxIndex < 0) then
             maxIndex := 0;
@@ -380,9 +345,11 @@ var
 begin
     Handled := true;
 
-    if (FSeriesList.Count = 0) then
+    // An X-axis series is required for zooming
+    if not Assigned(FXAxisSeries) then
         exit;
-    mainSeries := FSeriesList[0];
+
+    mainSeries := FXAxisSeries;
     if (mainSeries.Count = 0) or (Width <= 0) then
         exit;
 
@@ -456,7 +423,8 @@ begin
     inherited;
     rect := Self.LocalRect;
 
-    if (FSeriesList.Count = 0) or (FViewCount <= 1) then
+    // The chart requires an X-axis series to be set before it can draw anything.
+    if not Assigned(FXAxisSeries) or (FXAxisSeries.Count <= 1) or (FViewCount <= 1) then
     begin
         Canvas.Fill.Color := TAlphaColors.Gray;
         Canvas.FillText(rect, 'No Data', false, 1, [], TTextAlign.Center, TTextAlign.Center);
@@ -464,7 +432,7 @@ begin
     end;
 
     rangeInitialized := false;
-    mainSeries := FSeriesList[0];
+    mainSeries := FXAxisSeries;
 
     masterTotalCount := mainSeries.TotalCount;
     for series in FSeriesList do
@@ -566,179 +534,4 @@ begin
     end;
 end;
 
-{ TChartSeriesReceiver<T> }
-
-constructor TChartSeriesReceiver<T>.Create(const ALookback: TWriteable<Int64>);
-begin
-    inherited Create;
-    FLookback := ALookback;
-    FCurrData := TMycDataArray<T>.CreateEmpty;
-    FData := TWriteable<TMycDataArray<T>>.CreateWriteable(FCurrData).Protect;
-end;
-
-function TChartSeriesReceiver<T>.ProcessData(const Value: T): Boolean;
-begin
-    Result := true;
-    FCurrData := FCurrData.Add(Value, FLookback.Value);
-    FData.Value := FCurrData;
-end;
-
-{ TChartSeriesProcessor<T> }
-
-constructor TChartSeriesProcessor<T>.Create(AOwner: TMycChart; const ADataProvider: IMycDataProvider<T>);
-begin
-    inherited Create(AOwner);
-    FLock := TSpinLock.Create(false);
-    FDataSeries := TMycDataArray<T>.CreateEmpty;
-    FData := FDataSeries;
-    FDataProvider := ADataProvider;
-    FReceiver := TChartSeriesReceiver<T>.Create(AOwner.FLookback);
-    FReceiverTag := FDataProvider.Link(FReceiver);
-end;
-
-destructor TChartSeriesProcessor<T>.Destroy;
-begin
-    FDataProvider.Unlink(FReceiverTag);
-    inherited;
-end;
-
-function TChartSeriesProcessor<T>.GetCount: Int64;
-begin
-    Result := FData.Count;
-end;
-
-function TChartSeriesProcessor<T>.GetTotalCount: Int64;
-begin
-    Result := FData.TotalCount;
-end;
-
-procedure TChartSeriesProcessor<T>.Update;
-begin
-    FData := FReceiver.Data.Value;
-end;
-
-{ TChartOhlcSeries }
-
-constructor TChartOhlcSeries.Create(
-    AOwner: TMycChart;
-    const ADataProvider: IMycDataProvider<TDataPoint<TOhlcItem>>;
-    const AUpColor, ADownColor: TAlphaColor
-);
-begin
-    inherited Create(AOwner, ADataProvider);
-    FUpColor := AUpColor;
-    FDownColor := ADownColor;
-end;
-
-function TChartOhlcSeries.GetValueRange(First, Last: Int64; out MinValue, MaxValue: Double): Boolean;
-var
-    i: Int64;
-begin
-    MinValue := MaxDouble;
-    MaxValue := -MaxDouble;
-
-    for i := First to Last do
-    begin
-        var dp := Data.Items[i];
-        MinValue := Min(MinValue, dp.Data.Low);
-        MaxValue := Max(MaxValue, dp.Data.High);
-    end;
-    Result := (MinValue <> MaxDouble);
-end;
-
-procedure TChartOhlcSeries.Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>);
-var
-    i: Int64;
-    x, candleWidth: Single;
-    yOpen, yHigh, yLow, yClose: Single;
-    item: TDataPoint<TOhlcItem>;
-    isUp: boolean;
-begin
-    candleWidth := Max(2, 0.8 * Abs((XForm(First + 1) - XForm(First))));
-
-    for i := First to Last do
-    begin
-        item := Data.Items[i];
-        x := XForm(i);
-        yOpen := YForm(item.Data.Open);
-        yClose := YForm(item.Data.Close);
-        yHigh := YForm(item.Data.High);
-        yLow := YForm(item.Data.Low);
-        isUp := item.Data.Close >= item.Data.Open;
-
-        if isUp then
-            Canvas.Stroke.Color := FUpColor
-        else
-            Canvas.Stroke.Color := FDownColor;
-        Canvas.Stroke.Thickness := 1.0;
-
-        Canvas.DrawLine(TPointF.Create(x, yHigh), TPointF.Create(x, yLow), 1);
-
-        Canvas.Fill.Color := Canvas.Stroke.Color;
-        if isUp then
-            Canvas.FillRect(TRectF.Create(x - candleWidth / 2, yClose, x + candleWidth / 2, yOpen), 0, 0, AllCorners, 1)
-        else
-            Canvas.FillRect(TRectF.Create(x - candleWidth / 2, yOpen, x + candleWidth / 2, yClose), 0, 0, AllCorners, 1);
-    end;
-end;
-
-{ TChartLineSeries }
-
-constructor TChartLineSeries.Create(
-    AOwner: TMycChart;
-    const ADataProvider: IMycDataProvider<Double>;
-    const ALineColor: TAlphaColor;
-    ALineWidth: Single
-);
-begin
-    inherited Create(AOwner, ADataProvider);
-    FLineColor := ALineColor;
-    FLineWidth := ALineWidth;
-end;
-
-function TChartLineSeries.GetValueRange(First, Last: Int64; out MinValue, MaxValue: Double): Boolean;
-var
-    i: Int64;
-begin
-    MinValue := MaxDouble;
-    MaxValue := -MaxDouble;
-    for i := First to Last do
-    begin
-        var v := Data.Items[i];
-        if not IsNaN(v) then
-        begin
-            MinValue := Min(MinValue, v);
-            MaxValue := Max(MaxValue, v);
-        end;
-    end;
-    Result := (MinValue <> MaxDouble);
-end;
-
-procedure TChartLineSeries.Paint(const Canvas: TCanvas; First, Last: Int64; const XForm, YForm: TFunc<Double, Single>);
-var
-    points: TPathData;
-    i, n: Int64;
-begin
-    points := TPathData.Create;
-    try
-        // Skip warmup data
-        n := First;
-        while (n <= Last) and (IsNaN(Data[n])) do
-            inc(n);
-        if (n > Last) then
-            exit;
-
-        points.MoveTo(TPointF.Create(XForm(n), YForm(Data[n])));
-        for i := n + 1 to Last do
-            if not IsNaN(Data[i]) then
-                points.LineTo(TPointF.Create(XForm(i), YForm(Data[i])));
-
-        Canvas.Stroke.Color := FLineColor;
-        Canvas.Stroke.Thickness := FLineWidth;
-        Canvas.DrawPath(points, 1);
-    finally
-        points.Free;
-    end;
-end;
-
 end.

Src/Myc.Trade.DataPoint.pas

@@ -66,7 +66,7 @@ type
     private
         FProc: TProc;
     protected
-        function ProcessData(const Value: T): Boolean; override;
+        function ProcessData(const Value: T): Boolean; override; final;
     public
         constructor Create(const AProc: TProc);
     end;
@@ -81,6 +81,27 @@ type
         constructor Create(const Controller: IInterface; const AProc: TProc);
     end;
 
+    IMycConverter<S, T> = interface(IMycProcessor<S>)
+        function GetSender: IMycDataProvider<T>;
+        property Sender: IMycDataProvider<T> read GetSender;
+    end;
+
+    TMycConverter<S, T> = class abstract(TMycProcessor<S>, IMycConverter<S, T>)
+    private
+        FSender: TMycDataProvider<T>;
+        function GetSender: IMycDataProvider<T>;
+    protected
+        function ProcessData(const Value: S): Boolean; override; abstract;
+
+        // Broadcasts the given data to all linked processors.
+        procedure Broadcast(const Value: T);
+
+    public
+        constructor Create;
+        destructor Destroy; override;
+        property Sender: IMycDataProvider<T> read GetSender;
+    end;
+
     // An immutable time-ordered series of data points.
     // The most recent element has the logical index 0.
     IDataSeries<T> = interface
@@ -508,4 +529,29 @@ begin
     end;
 end;
 
+{ TMycConverter<S, T> }
+
+constructor TMycConverter<S, T>.Create;
+begin
+    inherited Create;
+    FSender := TMycDataProvider<T>.Create(Self);
+end;
+
+destructor TMycConverter<S, T>.Destroy;
+begin
+    FSender.Free;
+    inherited Destroy;
+end;
+
+procedure TMycConverter<S, T>.Broadcast(const Value: T);
+begin
+    var cValue := Value;
+    FSender.Notify(function(const Processor: IMycProcessor<T>): Boolean begin Result := Processor.ProcessData(cValue) end);
+end;
+
+function TMycConverter<S, T>.GetSender: IMycDataProvider<T>;
+begin
+    Result := FSender;
+end;
+
 end.