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MRIDUL DASHORA
20BCA
20BCA1482_MRIDUL DASHORA_Practical-
Student Name: MRIDUL DASHORA UID: 20BCA
Branch: BCA Section/Group: 20BCA5_A
Semester: 5th DateofPerformance: 10.09.
Subject Name: COMPUTER GRAPHICS LAB Subject Code: 20CAP316_B
A. Task to be done:
Summary of your previous attempts
B. Steps of Experiment
Declare p, q, x, y, r, d variables p, q are coordinates of the center of the circle r is the radius of the circle Enter the value of r Calculate d = 3 - 2r Initialize x= &nbsy= r Check if the whole circle is scan converted If x > = y Stop Plot eight points by using concepts of eight-way symmetry. The center is at (p, q). Current active pixel is (x, y). putpixel (x+p, y+q) putpixel (y+p, x+q) putpixel (-y+p, x+q) putpixel (-x+p, y+q) putpixel (-x+p, -y+q) putpixel (-y+p, -x+q) putpixel (y+p, -x+q) putpixel (x+p, -y-q) Find location of next pixels to be scanned If d < 0 then d = d + 4x + 6 increment x = x + 1 If d ≥ 0 then d = d + 4 (x - y) + 10 increment x = x + 1 decrement y = y – 1
C. Steps For Experiment/ Practical #include <graphics.h> #include <stdlib.h> #include <stdio.h> #include <conio.h> #include <math.h> void EightWaySymmetricPlot(int xc,int yc,int x,int y) { putpixel(x+xc,y+yc,RED); putpixel(x+xc,-y+yc,YELLOW); putpixel(-x+xc,-y+yc,GREEN); putpixel(-x+xc,y+yc,YELLOW); putpixel(y+xc,x+yc,12); putpixel(y+xc,-x+yc,14); putpixel(-y+xc,-x+yc,15); putpixel(-y+xc,x+yc,6); } void BresenhamCircle(int xc,int yc,int r) { int x=0,y=r,d=3-(2r); EightWaySymmetricPlot(xc,yc,x,y); while(x<=y) { if(d<=0) { d=d+(4x)+6; } else { d=d+(4x)-(4y)+10; y=y-1; } x=x+1; EightWaySymmetricPlot(xc,yc,x,y); } }
Learning outcomes (What I have learnt):
1. It is faster as compared to DDA (Digital Differential Analyzer) because it does not involve floating point calculations like DDA Algorithm. 2. Bresenham's Line Algorithm use fixed point, i.e., Integer Arithmetic... 3. Bresenham's Line Algorithm can draw circle and curves with more accurate than DDA Algorithm. E. Steps of Experiment
The input of the 2 end points of the line as (x1, y1) & (x2, y2) such that x1 != x2 and
y1 != y
Calculate dx = x2 – x1 and dy = y2 – y
if(dx>=dy) step=dx
else step=dy
xin = dx / step & yin = dy / step
x = x1 + 0.5 & y = y1 + 0.
for(k = 0; k < step; k++) {
x = x + xin y = y +
yin putpixel(x, y)
F. Steps For Experiment/ Practical #include <graphics.h> #include <stdio.h> #include <math.h> #include <dos.h> void main( ) { float x,y,x1,y1,x2,y2,dx,dy,step; int i,gd=DETECT,gm; initgraph(&gd,&gm,"c:\turboc3\bgi"); printf("Enter the value of x1 and y1 : "); scanf("%f%f",&x1,&y1); printf("Enter the value of x2 and y2: "); scanf("%f%f",&x2,&y2); dx=abs(x2-x1); dy=abs(y2-y1); if(dx>=dy) step=dx; else step=dy; dx=dx/step; dy=dy/step; x=x1; y=y1; i=1; while(i<=step) { putpixel(x,y,5); x=x+dx; y=y+dy; i=i+1; delay(100); }
Consider (x, y) as starting point and xendas maximum possible value of x. If dx < 0 Then x = x 2 y = y 2 xend=x 1 If dx > 0 Then x = x 1 y = y 1 xend=x 2 Generate point at (x,y)coordinates. Check if whole line is generated. If x > = xend Stop. Calculate co-ordinates of the next pixel If d < 0 Then d = d + i 1 If d ≥ 0 Then d = d + i 2 Increment y = y + 1 Increment x = x + 1 Draw a point of latest (x, y) coordinates I. Steps For Experiment/ Practical
#include<stdio.h>
#include<graphics.h>
void drawline #include<stdio.h>
#include<graphics.h>
void drawline(int x0, int y0, int x1, int y1)
int dx, dy, p, x, y;
dx=x1-x0;
dy=y1-y0;
x=x0;
y=y0;
p=2*dy-dx;
while(x<x1)
if(p>=0)
putpixel(x,y,7);
y=y+1;
p=p+2dy-2dx;
else
putpixel(x,y,7);
p=p+2*dy;}
x=x+1;
int main()
int gdriver=DETECT, gmode, error, x0, y0, x1, y1;
initgraph(&gdriver, &gmode, "c:\turboc3\bgi");
printf("Enter co-ordinates of first point: ");
scanf("%d%d", &x0, &y0);
printf("Enter co-ordinates of second point: ");
scanf("%d%d", &x1, &y1);
drawline(x0, y0, x1, y1);
return 0;
} (int x0, int y0, int x1, int y1)
int dx, dy, p, x, y;
dx=x1-x0;
dy=y1-y0;
x=x0;
y=y0;
p=2*dy-dx;
while(x<x1)
if(p>=0)
putpixel(x,y,7);
y=y+1;
p=p+2dy-2dx;
else
putpixel(x,y,7);
p=p+2*dy;}
1. It is faster as compared to DDA (Digital Differential Analyzer) because it does not involve floating point calculations like DDA Algorithm. 2. Bresenham's Line Algorithm use fixed point, i.e., Integer Arithmetic... 3. Bresenham's Line Algorithm can draw circle and curves with more accurate than DDA Algorithm.
Evaluation Grid:
Sr. No. Parameters Marks Obtained Maximum Marks
1. Demonstration and Performance
(Pre Lab Quiz)
2. Worksheet 10
3. Post Lab Quiz 5
