double TOfNextMajor(Edge *e, EdgeList *es, double sought_m ) {
/* We want to find t so that Mspline(t) = sought_m */
/* the curve is monotonic */
Spline1D *msp = &e->spline->splines[es->major];
double new_t;
if ( es->is_overlap ) {
/* if we've adjusted the height then we won't be able to find it restricting */
/* t between [0,1] as we do. So it's a special case. (this is to handle */
/* hstem hints) */
if ( e->max_adjusted && sought_m==e->mmax ) {
e->m_cur = sought_m;
return( e->up?1.0:0.0 );
}
new_t = IterateSplineSolve(msp,e->t_mmin,e->t_mmax,(sought_m+es->mmin)/es->scale,.001);
if ( new_t==-1 )
IError( "No Solution");
e->m_cur = (((msp->a*new_t + msp->b)*new_t+msp->c)*new_t + msp->d)*es->scale - es->mmin;
return( new_t );
} else {
Spline *sp = e->spline;
if ( sp->islinear ) {
new_t = e->t_cur + (sought_m-e->m_cur)/(es->scale * msp->c);
e->m_cur = (msp->c*new_t + msp->d)*es->scale - es->mmin;
return( new_t );
}
/* if we have a spline that is nearly horizontal at its max. endpoint */
/* then finding A value of t for which y has the right value isn't good */
/* enough (at least not when finding intersections) */
if ( sought_m+1>e->mmax ) {
e->m_cur = e->mmax;
return( e->t_mmax );
}
/* if we've adjusted the height then we won't be able to find it restricting */
/* t between [0,1] as we do. So it's a special case. (this is to handle */
/* hstem hints) */
if ( e->max_adjusted && sought_m==e->mmax ) {
e->m_cur = sought_m;
return( e->up?1.0:0.0 );
}
new_t = IterateSplineSolve(msp,e->t_mmin,e->t_mmax,(sought_m+es->mmin)/es->scale,.001);
if ( new_t==-1 )
IError( "No Solution");
e->m_cur = (((msp->a*new_t + msp->b)*new_t+msp->c)*new_t + msp->d)*es->scale - es->mmin;
return( new_t );
}
}
static double MonotonicFindY(Monotonic *m,double test,double old_t) {
double tstart, tend, t;
tstart = m->tstart; tend = m->tend;
if ( old_t!=-1 ) {
if ( m->yup )
tstart = old_t;
else
tend = old_t;
}
t = IterateSplineSolve(&m->s->splines[1],tstart,tend,test);
return( t );
}
