Mercurial > hg > svcore
view data/model/PowerOfTwoZoomConstraint.cpp @ 1567:36b4872e894a
Properly align window with signal, in oversampled case
author | Chris Cannam |
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date | Wed, 07 Nov 2018 11:47:24 +0000 (2018-11-07) |
parents | bf32b26d1dad |
children | 1ae6a19464a7 |
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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 "PowerOfTwoZoomConstraint.h" ZoomLevel PowerOfTwoZoomConstraint::getNearestZoomLevel(ZoomLevel requested, RoundingDirection dir) const { int blockSize; if (requested.zone == ZoomLevel::FramesPerPixel) { blockSize = getNearestBlockSize(requested.level, dir); if (blockSize > getMaxZoomLevel().level) { blockSize = getMaxZoomLevel().level; } return { requested.zone, blockSize }; } else { RoundingDirection opposite = dir; if (dir == RoundUp) opposite = RoundDown; else if (dir == RoundDown) opposite = RoundUp; blockSize = getNearestBlockSize(requested.level, opposite); if (blockSize > getMinZoomLevel().level) { blockSize = getMinZoomLevel().level; } if (blockSize == 1) { return { ZoomLevel::FramesPerPixel, 1 }; } else { return { requested.zone, blockSize }; } } } int PowerOfTwoZoomConstraint::getNearestBlockSize(int req, RoundingDirection dir) const { int max = getMaxZoomLevel().level; if (req > max) { return max; } for (int bs = 1; bs <= max; bs *= 2) { if (bs < req) { continue; } else if (bs == req) { return bs; } else { // bs > req if (dir == RoundNearest) { if (bs - req < req - bs/2) { return bs; } else { return bs/2; } } else if (dir == RoundDown) { return bs/2; } else { return bs; } } } return max; }