X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=flower%2Foffset.cc;h=db1654f2d3d517f0ef29b90a3d8750353f0a89d5;hb=a6a51abfd0195a3cf7d6ea095cf69808852f21ce;hp=258cc1782cc4a63ca2e39001a26fddb1402b8c30;hpb=d36e8ced83cfeabcf4ec3840ffe93a717a17ac4d;p=lilypond.git diff --git a/flower/offset.cc b/flower/offset.cc index 258cc1782c..db1654f2d3 100644 --- a/flower/offset.cc +++ b/flower/offset.cc @@ -1,75 +1,187 @@ /* - offset.cc -- implement Offset + This file is part of LilyPond, the GNU music typesetter. - source file of the GNU LilyPond music typesetter + Copyright (C) 1997--2015 Han-Wen Nienhuys - (c) 1997--1999 Han-Wen Nienhuys + LilyPond is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + LilyPond is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with LilyPond. If not, see . */ -#include -#ifndef STANDALONE -#include "string.hh" -#endif #include "offset.hh" - #ifndef STANDALONE -String -Offset::str () const +string +Offset::to_string () const { - String s; - s = String("(") + to_str (coordinate_a_[X_AXIS]) + ", " - + to_str (coordinate_a_[Y_AXIS]) + ")"; + string s; + s = string (" (") + ::to_string (coordinate_a_[X_AXIS]) + ", " + + ::to_string (coordinate_a_[Y_AXIS]) + ")"; return s; } #endif - /* free bsd fix by John Galbraith - */ - +*/ + Offset complex_multiply (Offset z1, Offset z2) { Offset z; - if(!isinf(z2[Y_AXIS])) - { - z[X_AXIS] = z1[X_AXIS] * z2[X_AXIS] - z1[Y_AXIS]*z2[Y_AXIS]; + if (!isinf (z2[Y_AXIS])) + { + z[X_AXIS] = z1[X_AXIS] * z2[X_AXIS] - z1[Y_AXIS] * z2[Y_AXIS]; z[Y_AXIS] = z1[X_AXIS] * z2[Y_AXIS] + z1[Y_AXIS] * z2[X_AXIS]; - } + } return z; } - - -Offset -complex_exp (Offset o) +static inline Real +atan2d (Real y, Real x) { - Real s = sin (o[Y_AXIS]); - Real c = cos (o[Y_AXIS]); - - Real r = exp (o[X_AXIS]); - - return Offset(r*c, r*s); + return atan2 (y, x) * (180.0 / M_PI); } Real -Offset::arg () const +Offset::angle_degrees () const { - return atan2 (y (), x()); + Real x = coordinate_a_ [X_AXIS]; + Real y = coordinate_a_ [Y_AXIS]; + + // We keep in the vicinity of multiples of 45 degrees here: this is + // where straightforward angles for straightforward angular + // relations are most expected. The factors of 2 employed in the + // comparison are not really perfect for that: sqrt(2)+1 would be + // the factor giving exact windows of 45 degrees rather than what we + // have here. It's just that 2 is likely to generate nicer code + // than 2.4 and the exact handover does not really matter. + // + // Comparisons here are chosen appropriately to let infinities end + // up in their "exact" branch. As opposed to the normal atan2 + // function behavior, this makes "competing" infinities result in + // NAN angles. + if (y < 0.0) + { + if (2*x < -y) + if (-x > -2*y) // x < 0, y < 0, |x| > |2y| + return -180 + atan2d (-y, -x); + else if (-2*x >= -y) // x < 0, y < 0, |y| < |2x| <= |4y| + return -135 + atan2d (x - y, -y - x); + else // y < 0, |y| >= |2x| + return -90 + atan2d (x, -y); + else if (x <= -2*y) // x > 0, y < 0, |y| <= |2x| < |4y| + return -45 + atan2d (x + y, x - y); + // Drop through for y < 0, x > |2y| + } + else if (y > 0.0) + { + if (2*x < y) + if (-x > 2*y) // x < 0, y >= 0, |x| > |2y| + return 180 - atan2d (y, -x); + else if (-2*x >= y) // x < 0, y >= 0, |y| < |2x| <= |4y| + return 135 - atan2d (x + y, y - x); + else // y >= 0, |y| >= |2x| + return 90 - atan2d (x, y); + else if (x <= 2*y) // x >= 0, y >= 0, |y| < |2x| < |4y| + return 45 - atan2d (x - y, x + y); + // Drop through for y > 0, x > |2y| + } + else + // we return 0 for (0,0). NAN would be an option but is a + // nuisance for getting back to rectangular coordinates. Strictly + // speaking, this argument would be just as valid for (+inf.0, + // +inf.0), but then infinities are already an indication of a + // problem in LilyPond. + return (x < 0.0) ? 180 : 0; + return atan2d (y, x); } + /** euclidian vector length / complex modulus - */ +*/ Real Offset::length () const { - return sqrt (sqr (x()) + sqr (y())); + return hypot (coordinate_a_[X_AXIS], coordinate_a_[Y_AXIS]); } -void -Offset::mirror (Axis a) + +bool +Offset::is_sane () const +{ + return !isnan (coordinate_a_[X_AXIS]) + && !isnan (coordinate_a_ [Y_AXIS]) + && !isinf (coordinate_a_[X_AXIS]) + && !isinf (coordinate_a_[Y_AXIS]); +} + +Offset +Offset::direction () const { - coordinate_a_[a] = - coordinate_a_[a]; + Offset d = *this; + if (isinf (d[X_AXIS])) + { + if (!isinf (d[Y_AXIS])) + return Offset ((d[X_AXIS] > 0.0 ? 1.0 : -1.0), 0.0); + } + else if (isinf (d[Y_AXIS])) + return Offset (0.0, (d[Y_AXIS] > 0.0 ? 1.0 : -1.0)); + else if (d[X_AXIS] == 0.0 && d[Y_AXIS] == 0.0) + return d; + // The other cases propagate or produce NaN as appropriate. + + d /= length (); + return d; +} + +Offset +Offset::swapped () const +{ + return Offset (coordinate_a_[Y_AXIS], coordinate_a_[X_AXIS]); +} + +Offset +offset_directed (Real angle) +{ + if (angle <= -360.0 || angle >= 360.0) + angle = fmod (angle, 360.0); + // Now |angle| < 360.0, and the absolute size is not larger than + // before, so we haven't lost precision. + if (angle <= -180.0) + angle += 360.0; + else if (angle > 180.0) + angle -= 360.0; + // Now -180.0 < angle <= 180.0 and we still haven't lost precision. + // We don't work with angles greater than 45 degrees absolute in + // order to minimize how rounding errors of M_PI/180 affect the + // result. That way, at least angles that are a multiple of 90 + // degree deliver the expected results. + // + // Sign of the sine is chosen to avoid -0.0 in results. This + // version delivers exactly equal magnitude on x/y for odd multiples + // of 45 degrees at the cost of losing some less obvious invariants. + + if (angle > 0) + if (angle > 90) + return Offset (sin ((90 - angle) * M_PI/180.0), + sin ((180 - angle) * M_PI/180.0)); + else + return Offset (sin ((90 - angle) * M_PI/180.0), + sin (angle * M_PI/180.0)); + else if (angle < -90) + return Offset (sin ((90 + angle) * M_PI/180.0), + sin ((-180 - angle) * M_PI/180.0)); + else + return Offset (sin ((90 + angle) * M_PI/180.0), + sin (angle * M_PI/180.0)); }