/*
   * see COPYRIGHT
   */
  
  
  /*
   * Screen for drawing the Bezier curves in text mode
   */
  
  struct screen {
  	unsigned physx;
  	unsigned physy;
  	unsigned cols;
  	unsigned rows;
  	unsigned xoff;
  	unsigned yoff;
  	unsigned minx;
  	unsigned miny;
  	char *dots;
  	double xscale;
  	double yscale;
  } screen;
  
  #define screenabsdot(x,y)	(screen.dots[(y)*screen.cols+(x)])
  #define screendot(x,y)	screenabsdot((x)+screen.xoff, (y)+screen.yoff)
  
  /* prototypes */
  double fmin(double a, double b);
  int abs(int x);
  void initscreen(unsigned physx, unsigned physy, 
  	unsigned cols, unsigned rows, unsigned xoff, unsigned yoff, 
  	unsigned minx, unsigned miny, unsigned maxx, unsigned maxy);
  void drawcurve(int mark, int ax,int ay, 
  	int bx,int by, int cx,int cy, int dx,int dy);
  void drawcurvedir(int mark, int ax,int ay, 
  	int bx,int by, int cx,int cy, int dx,int dy);
  void drawdot(int mark, int x, int y);
  void setabsdot(int mark, int x, int y);
  void setfdot(int mark, double x, double y);
  void printscreen(FILE *f);