mirror of
https://gitlab.com/freepascal.org/lazarus/lazarus.git
synced 2025-10-31 03:21:28 +01:00
96 lines
2.1 KiB
ObjectPascal
96 lines
2.1 KiB
ObjectPascal
unit mainform;
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{$mode objfpc}{$H+}
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interface
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uses
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Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ExtCtrls,
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StdCtrls, ComCtrls;
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type
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{ TForm1 }
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TForm1 = class(TForm)
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Label1: TLabel;
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timerRedraw: TTimer;
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trackSpeed: TTrackBar;
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procedure FormPaint(Sender: TObject);
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procedure timerRedrawTimer(Sender: TObject);
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procedure trackSpeedChange(Sender: TObject);
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private
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{ private declarations }
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public
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{ public declarations }
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CurStep: Double;
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procedure RotatePolygon(var APoints: array of TPoint; AAngle: Double);
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function RotatePoint(APoint, ACenter: TPoint; AAngle: Double): TPoint;
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end;
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var
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Form1: TForm1;
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implementation
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{$R *.lfm}
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{ TForm1 }
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procedure TForm1.timerRedrawTimer(Sender: TObject);
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begin
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CurStep := CurStep + 0.1;
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if CurStep > 360 then CurStep := 0;
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Form1.Invalidate;
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end;
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procedure TForm1.trackSpeedChange(Sender: TObject);
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begin
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timerRedraw.Interval := 1000 div trackSpeed.Position;
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end;
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procedure TForm1.RotatePolygon(var APoints: array of TPoint; AAngle: Double);
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var
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lCenter: TPoint;
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i: Integer;
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begin
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lCenter := Point(0, 0);
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for i := 0 to Length(APoints)-1 do
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begin
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lCenter.X := lCenter.X + APoints[i].X;
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lCenter.Y := lCenter.Y + APoints[i].Y;
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end;
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lCenter.X := lCenter.X div Length(APoints);
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lCenter.Y := lCenter.Y div Length(APoints);
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for i := 0 to Length(APoints)-1 do
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APoints[i] := RotatePoint(APoints[i], lCenter, AAngle);
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end;
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function TForm1.RotatePoint(APoint, ACenter: TPoint; AAngle: Double): TPoint;
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var
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dx, dy: Double;
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begin
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dx := (ACenter.Y * Sin(AAngle)) - (ACenter.X * Cos(AAngle)) + ACenter.X;
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dy := -(ACenter.X * Sin(AAngle)) - (ACenter.Y * Cos(AAngle)) + ACenter.Y;
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Result.X := Round((APoint.X * Cos(AAngle)) - (APoint.Y * Sin(AAngle)) + dx);
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Result.Y := Round((APoint.X * Sin(AAngle)) + (APoint.Y * Cos(AAngle)) + dy);
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end;
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procedure TForm1.FormPaint(Sender: TObject);
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var
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lPoints: array[0..2] of TPoint;
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begin
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lPoints[0].X := 100;
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lPoints[0].Y := 100;
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lPoints[1].X := 200;
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lPoints[1].Y := 0;
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lPoints[2].X := 200;
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lPoints[2].Y := 200;
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RotatePolygon(lPoints, CurStep);
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Canvas.Polygon(lPoints);
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end;
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end.
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