Chris@1552: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@1552: 
Chris@1552: /*
Chris@1552:     Sonic Visualiser
Chris@1552:     An audio file viewer and annotation editor.
Chris@1552:     Centre for Digital Music, Queen Mary, University of London.
Chris@1552:     
Chris@1552:     This program is free software; you can redistribute it and/or
Chris@1552:     modify it under the terms of the GNU General Public License as
Chris@1552:     published by the Free Software Foundation; either version 2 of the
Chris@1552:     License, or (at your option) any later version.  See the file
Chris@1552:     COPYING included with this distribution for more information.
Chris@1552: */
Chris@1552: 
Chris@1552: #include "RelativelyFineZoomConstraint.h"
Chris@1552: 
Chris@1552: #include <vector>
Chris@1552: #include <algorithm>
Chris@1552: #include <iostream>
Chris@1552: 
Chris@1552: using namespace std;
Chris@1552: 
Chris@1552: ZoomLevel
Chris@1552: RelativelyFineZoomConstraint::getNearestZoomLevel(ZoomLevel requested,
Chris@1552:                                                   RoundingDirection dir) const
Chris@1552: {
Chris@1552:     static vector<int> levels;
Chris@1552: 
Chris@1552:     int maxLevel = getMaxZoomLevel().level;
Chris@1552: 
Chris@1552:     if (levels.empty()) {
Chris@1552:         int level = 1;
Chris@1552:         while (level <= maxLevel) {
Chris@1552: //            cerr << level << " ";
Chris@1552:             levels.push_back(level);
Chris@1552:             int step = level / 10;
Chris@1552:             int pwr = 0;
Chris@1552:             while (step > 0) {
Chris@1552:                 ++pwr;
Chris@1552:                 step /= 2;
Chris@1552:             }
Chris@1552:             step = (1 << pwr);
Chris@1552:             level += step;
Chris@1552:         }
Chris@1552: //        cerr << endl;
Chris@1552:     }
Chris@1552: 
Chris@1552:     RoundingDirection effective = dir;
Chris@1552:     if (requested.zone == ZoomLevel::PixelsPerFrame) {
Chris@1552:         if (dir == RoundUp) effective = RoundDown;
Chris@1552:         else if (dir == RoundDown) effective = RoundUp;
Chris@1552:     }
Chris@1552: 
Chris@1552:     // iterator pointing to first level that is >= requested
Chris@1552:     auto i = lower_bound(levels.begin(), levels.end(), requested.level);
Chris@1552: 
Chris@1552:     ZoomLevel newLevel(requested);
Chris@1552: 
Chris@1552:     if (i == levels.end()) {
Chris@1552:         newLevel.level = maxLevel;
Chris@1552: 
Chris@1552:     } else if (*i == requested.level) {
Chris@1552:         newLevel.level = requested.level;
Chris@1552: 
Chris@1552:     } else if (effective == RoundUp) {
Chris@1552:         newLevel.level = *i;
Chris@1552: 
Chris@1552:     } else if (effective == RoundDown) {
Chris@1552:         if (i != levels.begin()) {
Chris@1552:             --i;
Chris@1552:         }
Chris@1552:         newLevel.level = *i;
Chris@1552: 
Chris@1552:     } else { // RoundNearest
Chris@1552:         if (i != levels.begin()) {
Chris@1552:             auto j = i;
Chris@1552:             --j;
Chris@1552:             if (requested.level - *j < *i - requested.level) {
Chris@1552:                 newLevel.level = *j;
Chris@1552:             } else {
Chris@1552:                 newLevel.level = *i;
Chris@1552:             }
Chris@1552:         }
Chris@1552:     }
Chris@1552: 
Chris@1552:     // canonicalise
Chris@1552:     if (newLevel.level == 1) {
Chris@1552:         newLevel.zone = ZoomLevel::FramesPerPixel;
Chris@1552:     }
Chris@1552: 
Chris@1552:     using namespace std::rel_ops;
Chris@1552:     if (newLevel > getMaxZoomLevel()) {
Chris@1552:         newLevel = getMaxZoomLevel();
Chris@1552:     } else if (newLevel < getMinZoomLevel()) {
Chris@1552:         newLevel = getMinZoomLevel();
Chris@1552:     }
Chris@1552:     
Chris@1552:     return newLevel;
Chris@1552: }
Chris@1552: 
Chris@1552: