// Reconstructed off the top of my head (not checking any literature or other code)... because I'm a pro
srecord noeq BresenhamLineDrawer(int x1, int y1, int x2, int y2) extends Meta is Iterable<Pt> {
  int mainStepX, mainStepY;
  int sideStepX, sideStepY;
  int i;
  int x, y;
  int fraction, increment, denominator;
  // denominator is also number of pixels to return (minus 1)
  
  *(Pt start, Pt end) {
    x1 = start.x;
    y1 = start.y;
    x2 = end.x;
    y2 = end.y;
  }
  
  simplyCached void init {
    x = x1; y = y1;
    if (abs(x2-x1) > abs(y2-y1)) {
      // go mainly horizontal (right or left)
      mainStepX = sideStepX = sign(x2-x1);
      sideStepY = sign(y2-y1);
      denominator = abs(x2-x1);
      increment = abs(y2-y1);
    } else {
      // go mainly vertical (up or down)
      mainStepY = sideStepY = sign(y2-y1);
      sideStepX = sign(x2-x1);
      denominator = abs(y2-y1);
      increment = abs(x2-x1);
    }
    fraction = denominator/2;
    if (scaffolding()) printVars BresenhamLineDrawer(+x1, +y1, +x2, +y2, +denominator);
  }
  
  Pt next() {
    init();
    
    if (i > denominator) null;
    
    Pt p = pt(x, y);
    if (i++ < denominator) {
      fraction += increment;
      if (fraction >= denominator) {
        fraction -= denominator;
        x += sideStepX;
        y += sideStepY;
      } else {
        x += mainStepX;
        y += mainStepY;
      }
      if (scaffolding())
        printVars BresenhamLineDrawer(+i, +fraction, +increment, +denominator, +x, +y, +p);
    }
    
    ret p;
  }
  
  public ItIt<Pt> iterator() { ret iff_null(-> next()); }
  
  public PtBuffer points() { ret new PtBuffer(iterator()); }
}