view data/model/PowerOfTwoZoomConstraint.cpp @ 490:c3fb8258e34d

* Make it possible to import an entire session from an RDF document.
  However, at the moment the timings of events appear to be constrained
  by how far the audio decoder has got through its audio file at the
  time the event is queried -- need to investigate.

/* -*- 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 "PowerOfTwoZoomConstraint.h"

size_t
PowerOfTwoZoomConstraint::getNearestBlockSize(size_t req,
					      RoundingDirection dir) const
{
    size_t result = 0;

    for (size_t bs = 1; ; bs *= 2) {
	if (bs >= req) {
	    if (dir == RoundNearest) {
		if (bs - req < req - bs/2) {
		    result = bs;
		    break;
		} else {
		    result = bs/2;
		    break;
		}
	    } else if (dir == RoundDown) {
		result = bs/2;
		break;
	    } else {
		result = bs;
		break;
	    }
	}
    }

    if (result > getMaxZoomLevel()) result = getMaxZoomLevel();
    return result;
}