Code for Program to rotate about reference point in C++ Programming

Code for Program to rotate about reference point in C++ Programming

# include <iostream.h>

# include <conio.h>

# include <graphics.h>

# include <math.h>

char IncFlag;

int PolygonPoints[4][2] =

    {{10,100},{110,100},{110,200},{10,200}};

int RefX = 10;

int RefY = 100;

void PolyLine()

{

    int iCnt;

    cleardevice();

    line(0,240,640,240);

    line(320,0,320,480);

    for (iCnt=0; iCnt<4; iCnt++)

    {

        line(PolygonPoints[iCnt][0],PolygonPoints[iCnt][1],

          PolygonPoints[(iCnt+1)%4][0],PolygonPoints[(iCnt+1)%4][1]);

    }

}

void Translate(int Direction)

{

    int iCnt;

    for (iCnt=0; iCnt<4; iCnt++)

    {

        PolygonPoints[iCnt][0] += Direction*RefX;

        PolygonPoints[iCnt][1] -= Direction*RefY;

    }

}

void Rotate()

{

    float Angle;

    int iCnt;

    int Tx,Ty;

    Translate(-1);

    cout<<endl;

    Angle = 30.0*(22.0/7.0)/180.0;

    for (iCnt=0; iCnt<4; iCnt++)

    {

        Tx = PolygonPoints[iCnt][0];

        Ty = PolygonPoints[iCnt][1];

        PolygonPoints[iCnt][0] = (Tx - 320)*cos(Angle) -

                     (Ty - 240)*sin(Angle) + 320;

        PolygonPoints[iCnt][1] = (Tx - 320)*sin(Angle) +

                     (Ty - 240)*cos(Angle) + 240;

    }

    Translate(1);

}

void main()

{

    int gDriver = DETECT, gMode;

    int iCnt;

    initgraph(&gDriver, &gMode, "C:\\TC\\BGI");

    for (iCnt=0; iCnt<4; iCnt++)

    {

        PolygonPoints[iCnt][0] += 320;

        PolygonPoints[iCnt][1] = 240 - PolygonPoints[iCnt][1];

    }

    PolyLine();

    getch();

    Rotate();

    PolyLine();

    getch();