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unit main;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, Forms, Controls, Graphics, Dialogs, ExtCtrls, StdCtrls,
TAGraph, TASeries, TAChartUtils, TATools, Types;
type
{ TMainForm }
TMainForm = class(TForm)
Chart: TChart;
ReferenceLine: TConstantLine;
Series: TUserDrawnSeries;
ChartToolset: TChartToolset;
DataPointDragTool: TDataPointDragTool;
cbShowDataPoints: TCheckBox;
Panel: TPanel;
procedure SeriesDraw(ACanvas: TCanvas; const ARect: TRect);
procedure SeriesGetBounds(var ABounds: TDoubleRect);
procedure cbShowDataPointsChange(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
Pen: TPen;
public
end;
var
MainForm: TMainForm;
implementation
{$R *.lfm}
uses
Math, TAGeometry;
const
COLOR_ABOVE = clRed;
COLOR_BELOW = clGreen;
RADIUS = 4;
type
TDataRec = record
x, y: Double;
end;
var
Data: array of TDataRec;
Extent: TDoubleRect;
function Intersect(p1, p2: TPoint; y: Integer): Integer;
begin
if p1.x = p2.x then
Result := p1.x
else
Result := round((p2.x - p1.x) / (p2.y - p1.y) * (y - p1.y) + p1.x);
end;
{ TMainForm }
procedure TMainForm.SeriesDraw(ACanvas: TCanvas;
const ARect: TRect);
procedure DrawCircle(p: TPoint; AColor: TColor; R: Integer);
begin
Chart.Drawer.SetBrushParams(bsSolid, AColor);
Chart.Drawer.Ellipse(P.x - R, P.y - R, P.x + R, P.y + R);
end;
function GetColor(y, yref: Integer): TColor;
begin
if y > yref then Result := COLOR_BELOW else Result := COLOR_ABOVE;
end;
var
i: Integer;
gp: TDoublePoint;
p1, p2, p3: TPoint;
yref: Integer;
x: Integer;
showDataPoints: Boolean;
begin
showDataPoints := cbShowDataPoints.Checked;
Chart.Drawer.Pen := Pen;
yref := Chart.YGraphToImage(ReferenceLine.Position);
i := 0;
gp := DoublePoint(Data[i].X, Data[i].Y);
p1 := Chart.GraphToImage(gp);
if showDataPoints then begin
Chart.Drawer.SetPenParams(psSolid, GetColor(p1.y, yref));
DrawCircle(p2, GetColor(p2.y, yref), RADIUS);
end;
for i:=0 to High(Data)-1 do begin
gp := DoublePoint(Data[i].X, Data[i].Y);
p2 := Chart.GraphToImage(gp);
if (p2.y - yref) * (p1.y - yref) < 0 then begin
p3 := Point(Intersect(p1, p2, yref), yref);
Chart.Drawer.SetPenParams(psSolid, GetColor(p1.y, yref));
Chart.Drawer.Line(p1, p3);
Chart.Drawer.SetPenParams(psSolid, GetColor(p2.y, yref));
Chart.Drawer.Line(p3, p2);
end else begin
Chart.Drawer.SetPenParams(psSolid, GetColor(p2.y, yref));
Chart.Drawer.Line(p1, p2);
end;
if showDataPoints then
DrawCircle(p2, GetColor(p2.y, yref), RADIUS);
p1 := p2;
end;
end;
procedure TMainForm.SeriesGetBounds(var ABounds: TDoubleRect);
begin
ABounds := Extent;
end;
procedure TMainForm.cbShowDataPointsChange(Sender: TObject);
begin
Chart.Invalidate;
end;
procedure TMainForm.FormCreate(Sender: TObject);
const
N = 20;
XMIN = -10;
XMAX = +10;
var
i: Integer;
x, y: Double;
begin
Chart.DoubleBuffered := true;
Pen := TPen.Create;
Pen.Width := 3;
SetLength(Data, N);
for i:=0 to N-1 do begin
Data[i].x := XMIN + (XMAX - XMIN) / (N - 1) * i;
// Data[i].y := sin(Data[i].x);
Data[i].y := (Random * 2 - 1) * 100;
end;
Extent.a.x := Data[0].x;
Extent.a.y := Data[0].y;
Extent.b.x := Data[0].x;
Extent.b.y := Data[0].y;
for i:= 1 to High(Data) do begin
Extent.a.x := Min(Extent.a.x, Data[i].x);
Extent.b.x := Max(Extent.b.x, Data[i].x);
Extent.a.y := Min(Extent.a.y, Data[i].y);
Extent.b.y := Max(Extent.b.y, Data[i].y);
end;
end;
procedure TMainForm.FormDestroy(Sender: TObject);
begin
Pen.Free;
end;
end.
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