51 lines
1.1 KiB
Plaintext
51 lines
1.1 KiB
Plaintext
procedure DrawCircle(Image: TImage; Radius: integer; Center: TPoint);
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var T1,T2: integer;
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var X,Y: integer;
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var Cnt: integer;
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procedure DrawPixels(X,Y: integer);
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{Draw pixel into all 8 octents}
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begin
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Image.Canvas.Pixels[Center.X + x, Center.Y + y]:=clRed;
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Image.Canvas.Pixels[Center.X - X, Center.Y + Y]:=clRed;
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Image.Canvas.Pixels[Center.X + X, Center.Y - Y]:=clRed;
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Image.Canvas.Pixels[Center.X - X, Center.Y - Y]:=clRed;
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Image.Canvas.Pixels[Center.X + Y, Center.Y + X]:=clRed;
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Image.Canvas.Pixels[Center.X - Y, Center.Y + X]:=clRed;
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Image.Canvas.Pixels[Center.X + y, Center.Y - X]:=clRed;
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Image.Canvas.Pixels[Center.X - Y, Center.Y - X]:=clRed;
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end;
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begin
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Cnt:=0;
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T1:= Radius div 32;
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{Start on X-axis}
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X:= Radius; Y:= 0;
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repeat
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begin
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DrawPixels(X, Y);
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Y:=Y + 1;
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T1:=T1 + Y;
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T2:=T1 - X;
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if T2 >= 0 then
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begin
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T1:=T2;
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X:=X - 1;
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end;
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Inc(Cnt);
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end
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until x < y;
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Form1.Caption:=IntToStr(Cnt);
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end;
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procedure ShowBrezCircle(Image: TImage);
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begin
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{Draw three times to make line thicker}
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DrawCircle(Image,100,Point(200,200));
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DrawCircle(Image,99,Point(200,200));
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DrawCircle(Image,98,Point(200,200));
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Image.Invalidate;
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end;
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