-#if wxUSE_SPLINES
-// ----------------------------------- spline code ----------------------------------------
-
-void wx_quadratic_spline(double a1, double b1, double a2, double b2,
- double a3, double b3, double a4, double b4);
-void wx_clear_stack();
-int wx_spline_pop(double *x1, double *y1, double *x2, double *y2, double *x3,
- double *y3, double *x4, double *y4);
-void wx_spline_push(double x1, double y1, double x2, double y2, double x3, double y3,
- double x4, double y4);
-static bool wx_spline_add_point(double x, double y);
-static void wx_spline_draw_point_array(wxDC *dc);
-
-wxList wx_spline_point_list;
-
-#define half(z1, z2) ((z1+z2)/2.0)
-#define THRESHOLD 5
-
-/* iterative version */
-
-void wx_quadratic_spline(double a1, double b1, double a2, double b2, double a3, double b3, double a4,
- double b4)
-{
- register double xmid, ymid;
- double x1, y1, x2, y2, x3, y3, x4, y4;
-
- wx_clear_stack();
- wx_spline_push(a1, b1, a2, b2, a3, b3, a4, b4);
-
- while (wx_spline_pop(&x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4)) {
- xmid = (double)half(x2, x3);
- ymid = (double)half(y2, y3);
- if (fabs(x1 - xmid) < THRESHOLD && fabs(y1 - ymid) < THRESHOLD &&
- fabs(xmid - x4) < THRESHOLD && fabs(ymid - y4) < THRESHOLD) {
- wx_spline_add_point( x1, y1 );
- wx_spline_add_point( xmid, ymid );
- } else {
- wx_spline_push(xmid, ymid, (double)half(xmid, x3), (double)half(ymid, y3),
- (double)half(x3, x4), (double)half(y3, y4), x4, y4);
- wx_spline_push(x1, y1, (double)half(x1, x2), (double)half(y1, y2),
- (double)half(x2, xmid), (double)half(y2, ymid), xmid, ymid);
- }
- }
-}
-
-/* utilities used by spline drawing routines */
-
-typedef struct wx_spline_stack_struct {
- double x1, y1, x2, y2, x3, y3, x4, y4;
-} Stack;
-
-#define SPLINE_STACK_DEPTH 20
-static Stack wx_spline_stack[SPLINE_STACK_DEPTH];
-static Stack *wx_stack_top;
-static int wx_stack_count;
-
-void wx_clear_stack()
-{
- wx_stack_top = wx_spline_stack;
- wx_stack_count = 0;
-}