Page 64 - DCAP313_LAB_ON_COMPUTER_GRAPHICS

Lab on Computer Graphics

Notes Enter the radius:
100

4.2.3 Advantage and Disadvantage of Midpoints Circle Drawing Algorithm
Following are the advantages and disadvantages of midpoint circle drawing algorithm:

Disadvantage
• Time consumption is high
• The distance between the pixels is not equal so we would not get smooth circle

Advantage
The midpoint method for deriving efficient scan-conversion algorithms to draw geometric curves
on raster displays in described. The method is general and is used to transform the nonparametric
equation f(x, y) = 0, which describes the curve, into an algorithms that draws the curve. Floating
point arithmetic and time-consuming
The midpoint circle algorithm sometimes known as Bresenham's circle
algorithm but it was not actually invented by Jack E. Bresenham. This algorithm
is related to work by Pitteway and Van Aken.

Self Assessment Questions
1. The general form of the circle equation comes directly from the distance formula and the
definition of a circle.
(a) True (b) False
2. In this (x – h) + (y – k) = r the value of r is called the ……………..
2
2
2
(a) radius (b) center point
(c) circle (d) fixed point
3. The equation of the circle is given by g(x, y) as:

2
2
(a) x + y = R (b) x + y + R = 0
2
2
2
2
2
2
(c) x + y – R = 0 (d) None of these
4. Which steps of implementing midpoint algorithm?
(a) Enter the center of the circle, (x, y), and its radius R
(b) Plot the pixel (xc, R) as the initial pixel
(c) Choose the next pixel depending on the value of pn. If pn < 1
(d) To draw the circle, start with the pixel (0, R) and initialize p to 1

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