Sutherland-Hodgeman Polygon Clipping

This program is for implementing Sutherland-Hodgeman Polygon Clipping . This is a part of Mumbai University MCA Colleges Computer Graphics CG MCA Sem 2

#include"stdio.h"

#include"conio.h"

#include"graphics.h"

#include"math.h"

void dda(int,int,int,int,int,int,int,int);

void dda(int x1,int y1,int x2,int y2,int xmin,int ymin,int xmax,int ymax)

{

            float dx,dy;

            float steps,x=x1,y=y1;

            int i=0;

            dx=x2-x1;

            dy=y2-y1;

            if(abs(dx)>=abs(dy))

                        steps=abs(dx);

            else

                        steps=abs(dy);

            dx=dx/steps;

            dy=dy/steps;

            while(i++<=steps)

            {

            if(x>=xmin && x<=xmax && y>=ymin && y<=ymax)

            {

                        line(x,y,x2,y2);

                        return;

            }

                        x=x+dx;

                        y=y+dy;

            }

}

void main()

{

            int n,gd,gm,x1,x2,y1,y2,xRec,yRec,b1,b2,b3,b4,l,b,yMin,yMax,xMin,xMax;

            float m;

            int a[10][4],i,j, flag=0,in=0;

            gd=DETECT;

            gm=DETECT;

            initgraph(&gm,&gd,"C:\\TC\\BGI");

            printf("Enter the length and breadth of the clipping window:\n");

            scanf("%d%d",&l,&b);

            printf("Enter the starting co-ord of the rectangle\n");

            scanf("%d%d",&xRec,&yRec);

            clrscr();

            rectangle(xRec,yRec,xRec+l,yRec+b);

            getch();

            clrscr();

            printf("Enter the no of lines\n");

            scanf("%d",&n);

            for(i=0;i<n;i++)

            {

                        printf("Enter the co-ord of line %d\n",i+1);

                        for(j=0;j<2;j++)

                        {

                                    scanf("%d",&a[i][j]);

                        }

                        a[i][2]=a[0][0];

                        a[i][3]=a[0][1];

                        if(i!=0)

                        {

                               a[i-1][2]=a[i][0];

                               a[i-1][3]=a[i][1];

                        }

            }

            clrscr();

            rectangle(xRec,yRec,xRec+l,yRec+b);

            for(i=0;i<n;i++)

            {

                        line(a[i][0],a[i][1],a[i][2],a[i][3]);

            }

            getch();

            clrscr();

            rectangle(xRec,yRec,xRec+l,yRec+b);

            xMin=xRec;

            yMin=yRec;

            xMax=xRec+l;

            yMax=yRec+b;

            for(i=0;i<n;i++)

            {

                        flag=0;

                        x1=a[i][0];

                        x2=a[i][2];

                        y1=a[i][1];

                        y2=a[i][3];

                        if(x1>=xMin && x1<=xMax && y1>=yMin && y1<=yMax)

                                    flag++;

                        if(x2>=xMin && x2<=xMax && y2>=yMin && y2<=yMax)

                                    flag++;

                        switch(flag)

                        {

                                    case 0:

                                                break;

case 1: if(x2>=xMin && x2<=xMax && y2>=yMin &&    y2<=yMax)

                                                {

                                                            dda(x1,y1,x2,y2,xMin,yMin,xMax,yMax);

                                                }

                                                else

                                                {

                                                            dda(x2,y2,x1,y1,xMin,yMin,xMax,yMax);

                                                }

                                                break;

                                    case 2: line(x1,y1,x2,y2);

                                                break;

                        }

            }

            getch();

            closegraph();

}



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