Mercurial > hg > svcore
view data/model/PowerOfSqrtTwoZoomConstraint.cpp @ 795:dc20458f6f85 qt5
Don't need to check for Dataquay, and in fact we can pick up the wrong version if we do. Just assume it is available (building in e.g. sv subdir configuration)
author | Chris Cannam |
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date | Tue, 07 May 2013 15:41:58 +0100 |
parents | 1424aa29ae95 |
children | e802e550a1f2 |
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/* -*- 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> size_t PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(size_t blockSize, RoundingDirection dir) const { int type, power; size_t rv = getNearestBlockSize(blockSize, type, power, dir); return rv; } size_t PowerOfSqrtTwoZoomConstraint::getNearestBlockSize(size_t blockSize, int &type, int &power, RoundingDirection dir) const { // std::cerr << "given " << blockSize << std::endl; size_t minCachePower = getMinCachePower(); if (blockSize < (1U << minCachePower)) { type = -1; power = 0; float val = 1.0, prevVal = 1.0; while (val + 0.01 < blockSize) { prevVal = val; val *= sqrt(2.f); } size_t rval; if (dir == RoundUp) rval = size_t(val + 0.01); else if (dir == RoundDown) rval = size_t(prevVal + 0.01); else if (val - blockSize < blockSize - prevVal) rval = size_t(val + 0.01); else rval = size_t(prevVal + 0.01); // SVDEBUG << "returning " << rval << endl; return rval; } unsigned int prevBase = (1 << minCachePower); unsigned int prevPower = minCachePower; unsigned int prevType = 0; size_t result = 0; for (unsigned int i = 0; ; ++i) { power = minCachePower + i/2; type = i % 2; unsigned 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; }