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Tuesday, February 7, 2012

Mid-Point Circle Drawing Algorithm..!!

Mid-Point Circle ( Xc, Yc, R):

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 P = 1 – R
3.  Repeat While (X < Y)
4.    Call Draw Circle(Xc, Yc, X, Y)
5.    Set X = X + 1
6.    If (P < 0) Then
7.      P = P + 2X + 6
8.    Else
9.      Set Y = Y – 1
10.      P = P + 2(X – Y) + 1
    [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

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