/* units.cpp * * Copyright (C) 2009, 2010 Francesco Abbate * * This program 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. * * This program 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 this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include #include #include "utils.h" #include "units.h" void units::init(double yinf, double ysup, double spacefact) { double del; if (ysup == yinf) ysup = yinf + 1.0; del = (ysup - yinf) / spacefact; order = (int) floor(log10(del)); double expf = pow(10, order); double delr = del / expf; if (5 <= delr) m_major = 5; else if (2 <= delr) m_major = 2; else m_major = 1; m_inf = (int) floor(yinf / (m_major * expf) + 1e-5); m_sup = (int) ceil (ysup / (m_major * expf) - 1e-5); nb_decimals = (order < 0 ? -order : 0); dmajor = m_major * expf; } void units::mark_label (char *lab, unsigned size, int mark) const { bool minus = (m_inf < 0); int asup = (minus ? -m_inf : m_sup); char fmt[16]; if (size < 16) return; if (nb_decimals == 0) { snprintf (lab, size, "%d", int(mark * dmajor)); lab[size-1] = '0円'; } else { int dec = (nb_decimals < 10 ? nb_decimals : 9); int base = (int) floor(asup * dmajor); int space = dec + (base> 0 ? (int)log10(base): 0) + 1 \ + (minus ? 1 : 0) + 1; snprintf (fmt, 16, "%%%i.%if", space, dec); fmt[15] = '0円'; snprintf (lab, size, fmt, mark * dmajor); lab[size-1] = '0円'; } } double units::mark_scale (double x) { double xinf = m_inf * dmajor, xsup = m_sup * dmajor; return (x - xinf) / (xsup - xinf); }