view data/model/PowerOfSqrtTwoZoomConstraint.cpp @ 1247:8f076d02569a piper

Make SVDEBUG always write to a log file -- formerly this was disabled in NDEBUG builds. I think there's little use to that, it just means that we keep adding more cerr debug output because we aren't getting the log we need. And SVDEBUG logging is not usually used in tight loops, I don't think the performance overhead is too serious.

Also update the About box.

/* -*- 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 "PowerOfSqrtTwoZoomConstraint.h"

#include <iostream>
#include <cmath>


int
PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(int blockSize,
						  RoundingDirection dir) const
{
    int type, power;
    int rv = getNearestBlockSize(blockSize, type, power, dir);
    return rv;
}

int
PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(int blockSize,
						  int &type, 
						  int &power,
						  RoundingDirection dir) const
{
//    cerr << "given " << blockSize << endl;

    int minCachePower = getMinCachePower();

    if (blockSize < (1 << minCachePower)) {
	type = -1;
	power = 0;
	float val = 1.0, prevVal = 1.0;
	while (val + 0.01 < blockSize) {
	    prevVal = val;
	    val *= sqrtf(2.f);
	}
	int rval;
	if (dir == RoundUp) rval = int(val + 0.01f);
	else if (dir == RoundDown) rval = int(prevVal + 0.01f);
	else if (val - float(blockSize) <
                 float(blockSize) - prevVal) rval = int(val + 0.01f);
	else rval = int(prevVal + 0.01);
//	SVDEBUG << "returning " << rval << endl;
	return rval;
    }

    int prevBase = (1 << minCachePower);
    int prevPower = minCachePower;
    int prevType = 0;

    int result = 0;

    for (unsigned int i = 0; ; ++i) {

	power = minCachePower + i/2;
	type = i % 2;

	int base;
	if (type == 0) {
	    base = (1 << power);
	} else {
	    base = (((unsigned int)((1 << minCachePower) * sqrt(2.) + 0.01))
		    << (power - minCachePower));
	}

//	SVDEBUG << "Testing base " << base << endl;

        if (base == blockSize) {
            result = base;
            break;
        }

	if (base > blockSize) {
	    if (dir == RoundNearest) {
		if (base - blockSize < blockSize - prevBase) {
		    dir = RoundUp;
		} else {
		    dir = RoundDown;
		}
	    }
	    if (dir == RoundUp) {
		result = base;
		break;
	    } else {
		type = prevType;
		power = prevPower;
		result = prevBase;
		break;
	    }
	}

	prevType = type;
	prevPower = power;
	prevBase = base;
    }

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