Circle Of Algorithm

Circle algorithm

Description: Here Xc and Yc denote the x – coordinate and y – coordinate of the center of the
circle. R is the radius.
1. Set X = 0 and Y = R
2. Set D = 3 – 2R
3. Repeat While (X < Y)
4. Call Draw Circle(Xc, Yc, X, Y)
5. Set X = X + 1
6. If (D < 0) Then
7. D = D + 4X + 6
8. Else
9. Set Y = Y – 1
10. D = D + 4(X – Y) + 10
[End of If]
11. Call Draw Circle(Xc, Yc, X, Y)
[End of While]
12. Exit
Draw Circle (Xc, Yc, X, Y):
1. Call PutPixel(Xc + X, Yc, + Y)
2. Call PutPixel(Xc - X, Yc, + Y)
3. Call PutPixel(Xc + X, Yc, - Y)
4. Call PutPixel(Xc - X, Yc, - Y)
5. Call PutPixel(Xc + Y, Yc, + X)
6. Call PutPixel(Xc - Y, Yc, + X)
7. Call PutPixel(Xc + Y, Yc, - X)
8. Call PutPixel(Xc - Y, Yc, - X)
9. Exit