void setup_gcs(void);
void drawRk(float), drawGk(float), drawXk(float), drawBk(float),
  drawRHOk(float), drawQk(float);
void drawR(float, float, float), drawX(float, float, float),
  drawG(float, float, float), drawB(float, float, float),
  drawRHO(float, float, float), drawLINE(float, float, float, float);
void drawSP(float, float), drawchart(void);

/* Non dovrebbero essere qui (?) */
void showtextstat(void), showcircdesc(void), exptlpln(char, char*);