Finally Done

Practical-7 || CG || Line Clipping ALgorithm.cpp

#include <iostream.h>
#include <conio.h>
#include <math.h>
#include <stdlib.h>
#include <dos.h>
#include <graphics.h>
#include <ctype.h>

//todo Global Declarations
int x1b, y1b, x2b, y2b;
//?Defining region codes
int INSIDE = 0; // 0000
int LEFT = 1;   // 0001
int RIGHT = 2;  // 0010
int BOTTOM = 4; // 0100
int TOP = 8;    // 1000

//todo Function Prototyping
void axisPlotting();
void lineClipping(double lx1, double lx2, double ly1, double ly2);
int computeCode(double x, double y);

//todo Function axis plotting
void axisPlotting()
{
    line(x1b, y1b, x1b, y2b);
    line(x1b, y1b, x2b, y1b);
    line(x2b, y2b, x2b, y1b);
    line(x2b, y2b, x1b, y2b);
}

//todo Function to calculate the ABRL regionCode
int computeCode(double x, double y)
{
    int code = INSIDE;

    if (x < x1b)
        code |= LEFT;
    else if (x > x2b)
        code |= RIGHT;
    if (y < y1b)
        code |= BOTTOM;
    else if (y > y2b)
        code |= TOP;

    return code;
}
//todo Function line clipping
void lineClipping(double x1, double x2, double y1, double y2)
{
    int code1 = computeCode(x1, y1);
    int code2 = computeCode(x2, y2);
    int accept = 0;
    while (accept == 0)
    {

        //!till here given the ABRL to both  the lines

        //todo If else statement for cases of ABRL
        if ((code1 == 0) && (code2 == 0))
        {
            accept = 1;
            cleardevice();
            axisPlotting();
            line(x1, y1, x2, y2);
            break;
        }
        else if (code1 & code2)
        {
            cout << "\nthe line is completely rejected";
            getch();
            cleardevice();
            axisPlotting();
            break;
        }
        else
        {

            int code_out;
            double x, y;

            if (code1 != 0)
                code_out = code1;
            else
                code_out = code2;

            if (code_out & TOP)
            {
                x = x1 + (x2 - x1) * (y2b - y1) / (y2 - y1);
                y = y2b;
            }
            else if (code_out & BOTTOM)
            {
                x = x1 + (x2 - x1) * (y1b - y1) / (y2 - y1);
                y = y1b;
            }
            else if (code_out & RIGHT)
            {
                y = y1 + (y2 - y1) * (x2b - x1) / (x2 - x1);
                x = x2b;
            }
            else if (code_out & LEFT)
            {
                y = y1 + (y2 - y1) * (x1b - x1) / (x2 - x1);
                x = x1b;
            }
            if (code_out == code1)
            {
                x1 = x;
                y1 = y;
                code1 = computeCode(x1, y1);
            }
            else
            {
                x2 = x;
                y2 = y;
                code2 = computeCode(x2, y2);
            }
        }
    }
    if (accept == 1)
    {
        cout << "Line accepted from " << x1 << ", "
             << y1 << " to " << x2 << ", " << y2 << endl;
        cleardevice();
        axisPlotting();
        line(x1, y1, x2, y2);
    }
}
//todo main function
void main()
{
    clrscr();
    int gd = DETECT, gm;
    float rx, ry, cx, cy;
    initgraph(&gd, &gm, "C:\\TURBOC3\\BGI");
    cleardevice();

    cout << "\n--------------Line Clipping Algorithm--------------";
    cout << "\nEnter Coordinates-- min and then max";

    cout << "\nEnter the Box diagonal coordinates (X1, Y1) & (X2, Y2) :\n ";
    cin >> x1b >> y1b;
    cin >> x2b >> y2b;
    axisPlotting();

    cout << "\nEnter the Line Coordinates (X1, Y1) & (X2, Y2) :\n ";
    double lx1, ly1, lx2, ly2;
    cin >> lx1 >> ly1;
    cin >> lx2 >> ly2;
    line(lx1, ly1, lx2, ly2);
    getch();

    lineClipping(lx1, lx2, ly1, ly2);
    cout << "\nAfter LineClipping Algorithm";
    getch();
    closegraph();
}