comparison base/RangeMapper.cpp @ 189:0703252c9fe8

* Add spectrum icon
* Start range mapper class for use in mapping between e.g. dial positions
  and underlying values

+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    This file copyright 2006 Chris Cannam.
+    
+    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 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#include "RangeMapper.h"
+
+#include <cassert>
+#include <cmath>
+
+#include <iostream>
+
+LinearRangeMapper::LinearRangeMapper(int minpos, int maxpos,
+				     float minval, float maxval,
+                                     QString unit) :
+    m_minpos(minpos),
+    m_maxpos(maxpos),
+    m_minval(minval),
+    m_maxval(maxval),
+    m_unit(unit)
+{
+    assert(m_maxval != m_minval);
+    assert(m_maxpos != m_minpos);
+}
+
+int
+LinearRangeMapper::getPositionForValue(float value) const
+{
+    int position = lrintf(((value - m_minval) / (m_maxval - m_minval))
+                          * (m_maxpos - m_minpos));
+    if (position < m_minpos) position = m_minpos;
+    if (position > m_maxpos) position = m_maxpos;
+    return position;
+}
+
+float
+LinearRangeMapper::getValueForPosition(int position) const
+{
+    float value = ((float(position - m_minpos) / float(m_maxpos - m_minpos))
+                   * (m_maxval - m_minval));
+    if (value < m_minval) value = m_minval;
+    if (value > m_maxval) value = m_maxval;
+    return value;
+}
+
+LogRangeMapper::LogRangeMapper(int minpos, int maxpos,
+                               float ratio, float minlog,
+                               QString unit) :
+    m_minpos(minpos),
+    m_maxpos(maxpos),
+    m_minlog(minlog),
+    m_unit(unit)
+{
+    assert(m_maxpos != m_minpos);
+
+    m_maxlog = (m_maxpos - m_minpos) / m_ratio + m_minlog;
+}
+
+int
+LogRangeMapper::getPositionForValue(float value) const
+{
+    float mapped = m_ratio * log10(value);
+    int position = lrintf(((mapped - m_minlog) / (m_maxlog - m_minlog))
+                          * (m_maxpos - m_minpos));
+    if (position < m_minpos) position = m_minpos;
+    if (position > m_maxpos) position = m_maxpos;
+    std::cerr << "LogRangeMapper::getPositionForValue: " << value << " -> "
+              << position << std::endl;
+    return position;
+}
+
+float
+LogRangeMapper::getValueForPosition(int position) const
+{
+    float value = powf(10, (position - m_minpos) / m_ratio + m_minlog);
+    std::cerr << "LogRangeMapper::getPositionForValue: " << position << " -> "
+              << value << std::endl;
+    return value;
+}
+