39             set(points[0], points[1],
  40                 points[2], points[3],
  41                 points[4], points[5],
  42                 points[6], points[7]);
  43             return;
  44         case 6:
  45             set(points[0], points[1],
  46                 points[2], points[3],
  47                 points[4], points[5]);
  48             return;
  49         default:
  50             throw new InternalError("Curves can only be cubic or quadratic");
  51         }
  52     }
  53 
  54     void set(double x1, double y1,
  55              double x2, double y2,
  56              double x3, double y3,
  57              double x4, double y4)
  58     {
  59         ax = 3.0d * (x2 - x3) + x4 - x1;
  60         ay = 3.0d * (y2 - y3) + y4 - y1;
  61         bx = 3.0d * (x1 - 2.0d * x2 + x3);
  62         by = 3.0d * (y1 - 2.0d * y2 + y3);
  63         cx = 3.0d * (x2 - x1);
  64         cy = 3.0d * (y2 - y1);




  65         dx = x1;
  66         dy = y1;
  67         dax = 3.0d * ax; day = 3.0d * ay;
  68         dbx = 2.0d * bx; dby = 2.0d * by;
  69     }
  70 
  71     void set(double x1, double y1,
  72              double x2, double y2,
  73              double x3, double y3)
  74     {


  75         ax = 0.0d; ay = 0.0d;
  76         bx = x1 - 2.0d * x2 + x3;
  77         by = y1 - 2.0d * y2 + y3;
  78         cx = 2.0d * (x2 - x1);
  79         cy = 2.0d * (y2 - y1);
  80         dx = x1;
  81         dy = y1;
  82         dax = 0.0d; day = 0.0d;
  83         dbx = 2.0d * bx; dby = 2.0d * by;
  84     }
  85 
  86     double xat(double t) {
  87         return t * (t * (t * ax + bx) + cx) + dx;
  88     }
  89     double yat(double t) {
  90         return t * (t * (t * ay + by) + cy) + dy;
  91     }
  92 
  93     double dxat(double t) {
  94         return t * (t * dax + dbx) + cx;
  95     }
  96 
  97     double dyat(double t) {
  98         return t * (t * day + dby) + cy;
  99     }

  39             set(points[0], points[1],
  40                 points[2], points[3],
  41                 points[4], points[5],
  42                 points[6], points[7]);
  43             return;
  44         case 6:
  45             set(points[0], points[1],
  46                 points[2], points[3],
  47                 points[4], points[5]);
  48             return;
  49         default:
  50             throw new InternalError("Curves can only be cubic or quadratic");
  51         }
  52     }
  53 
  54     void set(double x1, double y1,
  55              double x2, double y2,
  56              double x3, double y3,
  57              double x4, double y4)
  58     {
  59         final double dx32 = 3.0d * (x3 - x2);
  60         final double dy32 = 3.0d * (y3 - y2);
  61         final double dx21 = 3.0d * (x2 - x1);
  62         final double dy21 = 3.0d * (y2 - y1);
  63         ax = (x4 - x1) - dx32;
  64         ay = (y4 - y1) - dy32;
  65         bx = (dx32 - dx21);
  66         by = (dy32 - dy21);
  67         cx = dx21;
  68         cy = dy21;
  69         dx = x1;
  70         dy = y1;
  71         dax = 3.0d * ax; day = 3.0d * ay;
  72         dbx = 2.0d * bx; dby = 2.0d * by;
  73     }
  74 
  75     void set(double x1, double y1,
  76              double x2, double y2,
  77              double x3, double y3)
  78     {
  79         final double dx21 = (x2 - x1);
  80         final double dy21 = (y2 - y1);
  81         ax = 0.0d; ay = 0.0d;
  82         bx = (x3 - x2) - dx21;
  83         by = (y3 - y2) - dy21;
  84         cx = 2.0d * dx21;
  85         cy = 2.0d * dy21;
  86         dx = x1;
  87         dy = y1;
  88         dax = 0.0d; day = 0.0d;
  89         dbx = 2.0d * bx; dby = 2.0d * by;
  90     }
  91 
  92     double xat(double t) {
  93         return t * (t * (t * ax + bx) + cx) + dx;
  94     }
  95     double yat(double t) {
  96         return t * (t * (t * ay + by) + cy) + dy;
  97     }
  98 
  99     double dxat(double t) {
 100         return t * (t * dax + dbx) + cx;
 101     }
 102 
 103     double dyat(double t) {
 104         return t * (t * day + dby) + cy;
 105     }