DEPARTMENT OF
COMPUTER SCIENCE &
ENGINEERING
Experiment 4(A)
Student Name: Prince Kumar Singh UID: 22BCS11746
Branch: BE-CSE Section/Group:
612/A
Semester: 6 Date of
Performance:13/02/25 Subject Name: Computer Graphics Subject
Code:22CSH-352
with lab
1. Aim: Develop a program to draw a circle using the circle generator algorithm for a given center and radius.
2. Objective: To develop and implement the circle generator algorithm to draw a circle with a
given center and radius.
3. Algorithm:
• Initialize Graphics Mode: Detect the graphics driver and initialize the graphics mode.
• Input Values: Take user input for the center (xc, yc) and radius r of the circle.
• Plot Circle Points:
a) Use a loop from theta = 0 to 360 degrees.
b) Convert theta to radians and compute x and y using trigonometric functions.
c) Plot each point using putpixel(x, y, WHITE).
• Wait for User Input: Use getch() to pause execution.
• Close Graphics Mode: Terminate the graphics session.
4. Implementation/Code:
#include <graphics.h>
#include <conio.h>
#include <math.h>
#include <iostream.h>
void drawCircle(int xc, int yc, int r) {
1
DEPARTMENT OF
COMPUTER SCIENCE &
ENGINEERING
int gd = DETECT, gm;
initgraph(&gd, &gm, "C:\\TURBOC3\\BGI");
for (float theta = 0; theta <= 360; theta += 0.1) {
int x = xc + r * cos(theta * 3.14159 / 180);
int y = yc + r * sin(theta * 3.14159 / 180);
putpixel(x, y, WHITE);
}
getch();
closegraph();
}
int main() {
int xc, yc, r;
cout << "PRINCE KUMAR SINGH" << endl;
cout << "22BCS11746" << endl;
cout << "Enter center (xc, yc): ";
cin >> xc >> yc;
cout << "Enter radius: ";
cin >> r;
drawCircle(xc, yc, r);
return 0;
}
5. Output:
6. Learning Outcomes:
2
DEPARTMENT OF
COMPUTER SCIENCE &
ENGINEERING
Understand the implementation of the circle generation algorithm using parametric equations.
Develop skills in graphics programming using C++ with the <graphics.h> library.
Gain hands-on experience in plotting points based on trigonometric functions for drawing a circle.
3
DEPARTMENT OF
COMPUTER SCIENCE &
ENGINEERING
Experiment 4(B)
1. Aim: Develop a program to draw a circle using the midpoint circle algorithm for a given center
and radius.
2. Objective: To develop and implement the midpoint circle algorithm to draw a circle with a
given center and radius.
3. Algorithm:
a. Initialize Variables
1. Set the center of the circle (xc, yc).
2. Initialize starting point (x = 0, y = r).
3. Compute initial decision parameter p = 1 - r.
b. Plot Initial Points
1. Use 8-way symmetry to plot the first set of points using putpixel().
c. Iterate Until x <= y
1. Increment x.
2. Update decision parameter p:
a) If p < 0, update p as p = p + 2x + 1.
b) Otherwise, decrement y and update p as p = p + 2(x - y) + 1.
3. Plot the new points in all 8 symmetrical positions.
d. Exit Loop and Close Graphics
4. Implementation/Code:
#include <graphics.h>
#include <conio.h>
#include <iostream.h>
void drawCircle(int xc, int yc, int r) {
int gd = DETECT, gm;
initgraph(&gd, &gm, "C:\\TURBOC3\\BGI");
int x = 0, y = r;
int d = 1 - r;
while (x <= y) {
putpixel(xc + x, yc + y, WHITE);
putpixel(xc - x, yc + y, WHITE);
putpixel(xc + x, yc - y, WHITE);
putpixel(xc - x, yc - y, WHITE);
putpixel(xc + y, yc + x, WHITE);
putpixel(xc - y, yc + x, WHITE);
putpixel(xc + y, yc - x, WHITE);
putpixel(xc - y, yc - x, WHITE);
4
DEPARTMENT OF
COMPUTER SCIENCE &
ENGINEERING
x++;
if (d < 0)
d += 2 * x + 1;
else {
y--;
d += 2 * (x - y) + 1;
}
}
getch();
closegraph();
}
int main() {
int xc, yc, r;
cout << "PRINCE KUMAR SINGH" << endl;
cout << "22BCS11746" << endl;
cout << "Enter center (xc, yc): ";
cin >> xc >> yc;
cout<<"Enter radius: ";
cin>>r;
drawCircle(xc,yc,r);
return 0;
}
5. Output:
5
DEPARTMENT OF
COMPUTER SCIENCE &
ENGINEERING
6. Learning Outcome:
a. Understand the implementation of the Midpoint Circle Algorithm for efficient circle
drawing.
b. Develop skills in decision-based pixel plotting to minimize computations in graphics
programming.
c. Gain hands-on experience in optimizing circle drawing using symmetry and incremental
calculations.
