source file of the GNU LilyPond music typesetter
- (c) 1998 Jan Nieuwenhuizen <jan@digicash.com>
+ (c) 1998--2000 Jan Nieuwenhuizen <janneke@gnu.org>
*/
#include <math.h>
-#include "offset.hh"
+#include "config.h"
+
+#include "libc-extension.hh"
#include "bezier.hh"
-#include "dimen.hh"
-#include "paper-def.hh"
+#include "polynomial.hh"
-Bezier::Bezier (int steps_i)
+Real
+binomial_coefficient (Real over , int under)
{
- steps_i_ = steps_i;
- curve_ = new Offset [steps_i_ + 1];
+ Real x = 1.0;
+
+ while (under)
+ {
+ x *= over / Real (under);
+
+ over -= 1.0;
+ under --;
+ }
+ return x;
}
-Bezier::~Bezier ()
+void
+scale (Array<Offset>* arr_p, Real x , Real y)
{
- delete[] curve_;
+ for (int i = 0; i < arr_p->size (); i++)
+ {
+ (*arr_p)[i][X_AXIS] = x* (*arr_p)[i][X_AXIS];
+ (*arr_p)[i][Y_AXIS] = y* (*arr_p)[i][Y_AXIS];
+ }
}
-//from GNU gs3.33: ega.c
void
-Bezier::calc (Offset control[4])
-{
- Real dt = 1.0 / steps_i_;
- Real cx = 3.0 * (control[1].x() - control[0].x());
- Real bx = 3.0 * (control[2].x() - control[1].x()) - cx;
- Real ax = control[3].x() - (control[0].x() + cx + bx);
- Real cy = 3.0 * (control[1].y () - control[0].y ());
- Real by = 3.0 * (control[2].y () - control[1].y ()) - cy;
- Real ay = control[3].y () - (control[0].y () + cy + by);
- Real t = 0.0;
- int i = 0;
- while ( t <= 1.0 )
- {
- curve_[i].x() = ((ax * t + bx) * t + cx) * t + control[0].x();
- curve_[i++].y () = ((ay * t + by) * t + cy) * t + control[0].y ();
- t += dt;
- }
+rotate (Array<Offset>* arr_p, Real phi)
+{
+ Offset rot (complex_exp (Offset (0, phi)));
+ for (int i = 0; i < arr_p->size (); i++)
+ (*arr_p)[i] = complex_multiply (rot, (*arr_p)[i]);
+}
+
+void
+translate (Array<Offset>* arr_p, Offset o)
+{
+ for (int i = 0; i < arr_p->size (); i++)
+ (*arr_p)[i] += o;
}
+/*
+
+ Formula of the bezier 3-spline
+
+ sum_{j=0}^3 (3 over j) z_j (1-t)^(3-j) t^j
+ */
+
Real
-Bezier::y (Real x)
+Bezier::get_other_coordinate (Axis a, Real x) const
+{
+ Axis other = Axis ((a +1)%NO_AXES);
+ Array<Real> ts = solve_point (a, x);
+
+ Offset c = curve_point (ts[0]);
+ assert (fabs (c[a] - x) < 1e-8);
+
+ return c[other];
+}
+
+
+Offset
+Bezier::curve_point (Real t)const
{
- if (x <= curve_[0].x())
- return curve_[0].y ();
- for (int i = 1; i < steps_i_; i++ )
+ Real tj = 1;
+ Real one_min_tj = (1-t)*(1-t)*(1-t);
+
+ Offset o;
+ for (int j=0 ; j < 4; j++)
{
- if (x < curve_[i].x())
- {
- Real lin = (x - curve_[i-1].x()) / (curve_[i].x() - curve_[i-1].x());
- return curve_[i-1].y () + lin * (curve_[i].y () - curve_[i-1].y ());
- }
+ o += control_[j] * binomial_coefficient (3, j)
+ * pow (t,j) * pow (1-t, 3-j);
+
+ tj *= t;
+ if (1-t)
+ one_min_tj /= (1-t);
}
- return curve_[steps_i_-1].y ();
+
+#ifdef PARANOID
+ assert (fabs (o[X_AXIS] - polynomial (X_AXIS).eval (t))< 1e-8);
+ assert (fabs (o[Y_AXIS] - polynomial (Y_AXIS).eval (t))< 1e-8);
+#endif
+
+ return o;
}
-Bezier_bow::Bezier_bow (Paper_def* paper_l)
- : Bezier(10)
+Polynomial
+Bezier::polynomial (Axis a)const
{
- paper_l_ = paper_l;
+ Polynomial p (0.0);
+ for (int j=0; j <= 3; j++)
+ {
+ p += control_[j][a]
+ * Polynomial::power (j , Polynomial (0,1))*
+ Polynomial::power (3 - j, Polynomial (1,-1))*
+ binomial_coefficient(3, j);
+ }
+
+ return p;
}
+/**
+ Remove all numbers outside [0,1] from SOL
+ */
+Array<Real>
+filter_solutions (Array<Real> sol)
+{
+ for (int i = sol.size (); i--;)
+ if (sol[i] < 0 || sol[i] >1)
+ sol.del (i);
+ return sol;
+}
-/*
- from feta-sleur.ly
+/**
+ find t such that derivative is proportional to DERIV
+ */
+Array<Real>
+Bezier::solve_derivative (Offset deriv)const
+{
+ Polynomial xp=polynomial (X_AXIS);
+ Polynomial yp=polynomial (Y_AXIS);
+ xp.differentiate ();
+ yp.differentiate ();
+
+ Polynomial combine = xp * deriv[Y_AXIS] - yp * deriv [X_AXIS];
+
+ return filter_solutions (combine.solve ());
+}
+
- slurheightlimit#:=staffsize#/2;
- sluralpha:=slurheightlimit#*pi/2;
- % slurratio:=1/3;
- slurratio:=0.3333;
- slurbeta:=3/4*pi*slurratio/sluralpha;
+/*
+ Find t such that curve_point (t)[AX] == COORDINATE
+*/
+Array<Real>
+Bezier::solve_point (Axis ax, Real coordinate) const
+{
+ Polynomial p(polynomial (ax));
+ p.coefs_[0] -= coordinate;
+
+ Array<Real> sol (p.solve ());
+ return filter_solutions (sol);
+}
- b#:=length(dx#,dy#);
- % ugh: huh? 2/5
- indent#:=2/5*sluralpha*atan(slurbeta*b#);
- height:=(indent+h)*d;
- z1=(0,0);
- z2=(b,0);
- z3=(indent,height);
- z4=(b-indent,height);
+/**
+ Compute the bounding box dimensions in direction of A.
+ */
+Interval
+Bezier::extent (Axis a)const
+{
+ int o = (a+1)%NO_AXES;
+ Offset d;
+ d[Axis (o)] =1.0;
+ Interval iv;
+ Array<Real> sols (solve_derivative (d));
+ sols.push (1.0);
+ sols.push (0.0);
+ for (int i= sols.size (); i--;)
+ {
+ Offset o (curve_point (sols[i]));
+ iv.unite (Interval (o[a],o[a]));
+ }
+ return iv;
+}
- boogje:=boogje rotated angle(dxs,dys);
-*/
+/**
+ Flip around axis A
+ */
void
-Bezier_bow::calc (Real dx, Real dy, Real h, Real d)
-{
- // ugh
- Real pi = M_PI;
- // ugh
- Real staffsize_f = paper_l_->get_var ("barsize");
- Real height_limit = staffsize_f;
- Real alpha = height_limit * pi / 2.0;
- Real ratio = 1.0/3.0;
- Real beta = 3.0/4.0 * pi * ratio/alpha;
-
- Real b = sqrt (dx * dx + dy * dy);
- Real indent = 2.0/5.0 * alpha * atan (beta * b);
- // ugh, ugly height hack, see lily-ps-defs.tex
- Real height = (indent + h) * d;
-
- Offset control[4];
- control[0] = Offset(0, 0);
- control[1] = Offset(indent, height);
- control[2] = Offset(b - indent, height);
- control[3] = Offset( b, 0 );
-
- Real phi = dx ? atan (dy/dx) : sign (dy) * pi / 2.0;
- Real sphi = sin (phi);
- Real cphi = cos (phi);
- for (int i = 1; i < 4; i++)
+Bezier::scale (Real x, Real y)
+{
+ for (int i = CONTROL_COUNT; i--;)
{
- control[i].x() = cphi * control[i].x() - sphi * control[i].y ();
- control[i].y () = sphi * control[i].x() + cphi * control[i].y ();
+ control_[i][X_AXIS] = x * control_[i][X_AXIS];
+ control_[i][Y_AXIS] = y * control_[i][Y_AXIS];
}
- Bezier::calc (control);
}
+void
+Bezier::rotate (Real phi)
+{
+ Offset rot (complex_exp (Offset (0, phi)));
+ for (int i = 0; i < CONTROL_COUNT; i++)
+ control_[i] = complex_multiply (rot, control_[i]);
+}
+
+void
+Bezier::translate (Offset o)
+{
+ for (int i = 0; i < CONTROL_COUNT; i++)
+ control_[i] += o;
+}
+
+void
+Bezier::assert_sanity () const
+{
+ for (int i=0; i < CONTROL_COUNT; i++)
+ assert (!isnan (control_[i].length ())
+ && !isinf (control_[i].length ()));
+}
+
+void
+Bezier::reverse ()
+{
+ Bezier b2;
+ for (int i =0; i < CONTROL_COUNT; i++)
+ b2.control_[CONTROL_COUNT-i-1] = control_[i];
+ *this = b2;
+}
projects / lilypond.git / blobdiff