Implementación de algoritmos/Geometría/Algoritmo del punto medio para circunferencias

Circunferencias

Java

void CircleMidPoint(Graphics g, int xc, int yc, int r){
  int x, y, p;
  x = 0;
  y = r;
  p = 1 - r;
  PlotPoint(g,xc,yc,x,y);
  /* se cicla hasta trazar todo un octante */
  while (x < y){
    x = x + 1;
    if (p < 0)
      p = p + 2*x + 1;
    else {
      y = y - 1;
      p = p + 2*(x - y) + 1;
    }
    PlotPoint(g,xc,yc,x,y);
  }}

Cónicas

Elipse (En java)

 public void Elipse(Graphics g, int xc, int yc, int rx, int ry){
  int x, y, p, px, py;
  int rx2, ry2, tworx2, twory2;
  ry2 = ry*ry;
  rx2 = rx*rx;
  twory2 = 2 * ry2;
  tworx2 = 2 * rx2;
 /* región 1 */
  x = 0;
  y = ry;
  PlotPoint(x,y);
  p = (int)Math.round(ry2 - rx2*ry + 0.25*rx2);
  px = 0;
  py = tworx2*y;
  while (px < py) { /* se cicla hasta trazar la región 1 */
    x = x + 1;
    px = px + twory2;
    if (p < 0)
      p = p + ry2 + px;
    else {
      y = y - 1;
      py = py - tworx2;
      p = p + ry2 + px - py;
    }
    PlotPoint(x,y);
  }
 /* región 2 */
  p = (int)Math.round(ry2*(x+0.5)*(x+0.5) + rx2*(y-1)*(y-1) - rx2*ry2);
  px = 0;
  py = tworx2*y;
  while (y > 0) { /* se cicla hasta trazar la región 2 */
    y = y - 1;
    py = py - tworx2;
    if (p > 0)
      p = p + rx2 - py;
    else {
      x = x + 1;
      px = px + twory2;
      p = p + rx2 + py + px;
    }
    PlotPoint(x,y);
  }
 }

Elipse (En C)

 #include<stdio.h>
 #include<graphics.h>
 #include<math.h>
 #include<conio.h>
 void main()
  {
    float x,y, rx2, ry2,p1,p2;
    int xc, yc, gm, gd=DETECT, rx, ry;
    printf("ENTER RX AND RY:");
    scanf("%d %d",&rx,&ry);
    printf("ENTER THE CO-ORDINATES OF THE CENTER:");
    scanf("%d %d",&xc,&yc);
    initgraph(&gd,&gm," ");
    putpixel(xc, yc,15);
    x=0;
    y=ry;
    rx2=pow(rx,2);
    ry2=pow(ry,2);
    p1=ry2-(rx2*ry)+(0.25*rx2);
    while((ry2*x)<(rx2*y))
       {
       if(p1<0)
          { x++;
            p1=p1+(2*ry2*x)+ry2;
          }
       else
          {
            x++; y--;
            p1=p1+(2*ry2*x)-(2*rx2*y)+ry2;
          }
       putpixel(xc+x, yc+y,15);
       putpixel(xc-x,yc+y,15);
       putpixel(xc+x,yc-y,15);
       putpixel(xc-x,yc-y,15);
       }
    p2=(ry2)*pow((x+0.5),2)+(rx2)*pow((y-1),2)-(rx2*ry2);
    while(y>0)
       {
          if (p2>0)
          {
            y--;
            p2=p2-(2*rx2*y) +rx2;
          }
          else
          {
            x++; y--;
            p2=p2+ (2*ry2*x)-(2*rx2*y)+rx2;
          }
          putpixel(xc+x, yc+y,15);
          putpixel(xc-x,yc+y,15);
          putpixel(xc+x,yc-y,15);
          putpixel(xc-x,yc-y,15);
       }
    getch();
    closegraph();
 }