RosettaCodeData/Task/Polyspiral/Delphi/polyspiral.delphi

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procedure PolySpiral(Image: TImage);
var Step,Angle,LineLen,I: integer;
var X,Y,X1,Y1: double;
begin
AbortFlag:=False;
ClearImage(Image,clBlack);
Image.Canvas.Pen.Width:=1;
while true do
begin
Image.Canvas.Pen.Color:=clYellow;
Step:=(Step + 5) mod 360;
X:=Image.Width/2;
Y:=Image.Height/2;
LineLen:=5;
angle:=Step;
for I:=1 to 150 do
begin
X1:=X + LineLen*cos(DegToRad(angle));
Y1:=Y + LineLen*sin(DegToRad(angle));
Image.Canvas.MoveTo(Round(X),Round(Y));
Image.Canvas.LIneTo(Round(X1),Round(Y1));
Image.Repaint;
LineLen:=LineLen+2;
Angle:=(Angle + Step) mod 360;
X:=X1;
Y:=Y1;
end;
if Application.Terminated then exit;
if AbortFlag then break;
Sleep(1200);
Application.ProcessMessages;
WaitForButton;
ClearImage(Image,clBlack);
end;
end;