diff --git a/components/tachart/tacustomseries.pas b/components/tachart/tacustomseries.pas
index 791305bdaf..37eda427b0 100644
--- a/components/tachart/tacustomseries.pas
+++ b/components/tachart/tacustomseries.pas
@@ -262,7 +262,7 @@ type
     function GetNearestPoint(
       const AParams: TNearestPointParams;
       out AResults: TNearestPointResults): Boolean; override;
-    procedure MovePoint(var AIndex: Integer; const ANewPos: TPoint); override;
+    procedure MovePoint(var AIndex: Integer; const ANewPos: TDoublePoint); override;
     property MarkPositions: TLinearMarkPositions
       read FMarkPositions write SetMarkPositions default lmpOutside;
     property UseReticule: Boolean
@@ -1055,15 +1055,12 @@ begin
 end;
 
 procedure TBasicPointSeries.MovePoint(
-  var AIndex: Integer; const ANewPos: TPoint);
-var
-  p: TDoublePoint;
+  var AIndex: Integer; const ANewPos: TDoublePoint);
 begin
   if not InRange(AIndex, 0, Count - 1) then exit;
-  p := FChart.ImageToGraph(ANewPos);
   with ListSource do begin
-    AIndex := SetXValue(AIndex, p.X);
-    SetYValue(AIndex, p.Y);
+    AIndex := SetXValue(AIndex, ANewPos.X);
+    SetYValue(AIndex, ANewPos.Y);
   end;
 end;
 
diff --git a/components/tachart/tagraph.pas b/components/tachart/tagraph.pas
index 35a6d64da7..bcce60c11b 100644
--- a/components/tachart/tagraph.pas
+++ b/components/tachart/tagraph.pas
@@ -81,7 +81,8 @@ type
     procedure Draw(ADrawer: IChartDrawer); virtual; abstract;
     function GetGraphBounds: TDoubleRect; virtual; abstract;
     function IsEmpty: Boolean; virtual; abstract;
-    procedure MovePoint(var AIndex: Integer; const ANewPos: TPoint); virtual;
+    procedure MovePoint(var AIndex: Integer; const ANewPos: TPoint); overload; inline;
+    procedure MovePoint(var AIndex: Integer; const ANewPos: TDoublePoint); overload; virtual;
 
     property Active: Boolean read FActive write SetActive default true;
     property Depth: TChartDistance read FDepth write SetDepth default 0;
@@ -1581,11 +1582,17 @@ begin
 end;
 
 procedure TBasicChartSeries.MovePoint(
-  var AIndex: Integer; const ANewPos: TPoint);
+  var AIndex: Integer; const ANewPos: TDoublePoint);
 begin
   Unused(AIndex, ANewPos)
 end;
 
+procedure TBasicChartSeries.MovePoint(
+  var AIndex: Integer; const ANewPos: TPoint);
+begin
+  MovePoint(AIndex, FChart.ImageToGraph(ANewPos));
+end;
+
 procedure TBasicChartSeries.UpdateMargins(
   ADrawer: IChartDrawer; var AMargins: TRect);
 begin
diff --git a/components/tachart/taseries.pas b/components/tachart/taseries.pas
index 514049a146..941141bfa4 100644
--- a/components/tachart/taseries.pas
+++ b/components/tachart/taseries.pas
@@ -269,7 +269,7 @@ type
     function GetNearestPoint(
       const AParams: TNearestPointParams;
       out AResults: TNearestPointResults): Boolean; override;
-    procedure MovePoint(var AIndex: Integer; const ANewPos: TPoint); override;
+    procedure MovePoint(var AIndex: Integer; const ANewPos: TDoublePoint); override;
 
   published
     property Active default true;
@@ -710,21 +710,17 @@ begin
   Result := FPen.Color;
 end;
 
-procedure TConstantLine.MovePoint(var AIndex: Integer; const ANewPos: TPoint);
+procedure TConstantLine.MovePoint(
+  var AIndex: Integer; const ANewPos: TDoublePoint);
 begin
   Unused(AIndex);
-  if LineStyle = lsVertical then
-    Position := GraphToAxisX(FChart.XImageToGraph(ANewPos.X))
-  else
-    Position := GraphToAxisX(FChart.YImageToGraph(ANewPos.Y));
+  Position :=
+    GraphToAxisX(TDoublePointBoolArr(ANewPos)[LineStyle = lsHorizontal]);
 end;
 
 procedure TConstantLine.SavePosToCoord(var APoint: TDoublePoint);
 begin
-  if LineStyle = lsVertical then
-    APoint.X := Position
-  else
-    APoint.Y := Position;
+  TDoublePointBoolArr(APoint)[LineStyle = lsHorizontal] := Position;
 end;
 
 procedure TConstantLine.SetArrow(AValue: TChartArrow);