CG_Practical01.cpp

#include <conio.h>
#include <iostream>
#include <graphics.h>
#include <stdlib.h>
using namespace std;
class point
{
public:
  int x, y;
};
class poly
{
private:
  point p[20];
  int inter[20], x, y;
  int v, xmin, ymin, xmax, ymax;

public:
  int c;
  void read();
  void calcs();
  void display();
  void ints(float);
  void sort(int);
};
void poly::read()
{
  int i;
  cout << "\n Scan Fill Algorithm ";
  cout << "\n Enter Number Of Vertices Of Polygon: ";
  cin >> v;
  if (v > 2)
  {
    for (i = 0; i < v; i++) // ACCEPT THE VERTICES
    {
      cout << "\nEnter co-ordinate no. " << i + 1 << " : ";
      cout << "\n\tx" << (i + 1) << "=";
      cin >> p[i].x;
      cout << "\n\ty" << (i + 1) << "=";
      cin >> p[i].y;
    }
    p[i].x = p[0].x;
    p[i].y = p[0].y;
    xmin = xmax = p[0].x;
    ymin = ymax = p[0].y;
  }
  else
    cout << "\n Enter valid no. of vertices.";
}
void poly::calcs()
{
  for (int i = 0; i < v; i++)
  {
    if (xmin > p[i].x)
      xmin = p[i].x;
    if (xmax < p[i].x)
      xmax = p[i].x;
    if (ymin > p[i].y)
      ymin = p[i].y;
    if (ymax < p[i].y)
      ymax = p[i].y;
  }
}
void poly::display()
{
  int ch1;
  char ch = 'y';
  float s, s2;
  do
  {
    cout << "\n\nMENU:";
    cout << "\n\n\t1 . Scan line Fill ";
    cout << "\n\n\t2 . Exit ";
    cout << "\n\nEnter your choice:";
    cin >> ch1;
    switch (ch1)
    {
    case 1:
      s = ymin + 0.01;
      delay(100);
      cleardevice();
      while (s <= ymax)
      {
        ints(s);
        sort(s);
        s++;
      }
      break;
    case 2:
      exit(0);
    }
    cout << "Do you want to continue?: ";
    cin >> ch;
  } while (ch == 'y' || ch == 'Y');
}
void poly::ints(float z)
{
  int x1, x2, y1, y2, temp;
  c = 0;
  for (int i = 0; i < v; i++)
  {
    x1 = p[i].x;
    y1 = p[i].y;
    x2 = p[i + 1].x;
    y2 = p[i + 1].y;
    if (y2 < y1)
    {
      temp = x1;
      x1 = x2;
      x2 = temp;
      temp = y1;
      y1 = y2;
      y2 = temp;
    }
    if (z <= y2 && z >= y1)
    {
      if ((y1 - y2) == 0)
        x = x1;
      else
      {
        x = ((x2 - x1) * (z - y1)) / (y2 - y1);
        x = x + x1;
      }
      if (x <= xmax && x >= xmin)
        inter[c++] = x;
    }
  }
}
void poly::sort(int z) // sorting
{
  int temp, j, i;
  for (i = 0; i < v; i++)
  {
    line(p[i].x, p[i].y, p[i + 1].x, p[i + 1].y);
  }
  delay(100);
  for (i = 0; i < c; i += 2)
  {
    delay(100);
    line(inter[i], z, inter[i + 1], z);
  }
}
int main() // main
{
  int cl;
  int gd = DETECT, gm;
  initgraph(&gd, &gm,  (char *)"");
  poly x;
  x.read();
  x.calcs();
  cleardevice();
  cout << "\n\tEnter The Color You Want :(In Range 0 To 15 )->"; // selecting color
  cin >> cl;
  setcolor(cl);
  x.display();

  closegraph(); // closing graph
  getch();
  return 0;
}