#include <stdio.h>
#include <MacLib.h>

int root(int c)
{
  int r;

  for (r=0; r*r < c ; r++)
    ;
  return r;
}

void PaintPoint(Point centre,int h, int v)
{
  int y = centre.v + v;
  int x = centre.h + h;

  printf("Point : %d %d\n",h,v);
  DrawLine(x,y,x,y);
  y = centre.v + v;
  x = centre.h - h;
  DrawLine(x,y,x,y);
  y = centre.v - v;
  x = centre.h - h;
  DrawLine(x,y,x,y);
  y = centre.v - v;
  x = centre.h + h;
  DrawLine(x,y,x,y);
}

void cercle(Point centre, int rr)
{
  int h,v;
  int delta = 0;
  int r = root(rr);

  v=r;
  h=0;
  do {
    PaintPoint(centre,h,v);
    delta += 2*h+1;
    h++;
    if (delta <= 0)
      continue;
    delta += -2*v+1;
    v--;
    if (delta <= 0)
      continue;
    h--;
    delta -= 2*h-1;
  } while (v >= 0);
}

void main(void)
{
  Point p,q;
  int r,old;


  InitQuickDraw();

  for (;;) {
    WaitClickDown();
    GetMouse(&p);
    PenMode(patXor);
    PenPat(gray);
    do {
      GetMouse(&q);
      old = r = (p.h-q.h)*(p.h-q.h)+(p.v-q.v)*(p.v-q.v);
      cercle(p,r);
      printf("r = %d\n",root(r));
      do {
        GetMouse(&q);
        r = (p.h-q.h)*(p.h-q.h)+(p.v-q.v)*(p.v-q.v);
      } while ((old == r) && Button());
      cercle(p,old);
    } while (Button());
    PenMode(patCopy);
    PenPat(black);
    cercle(p,r);
  }
}