Mercurial > hg > svcore
view base/ZoomConstraint.h @ 461:2019d89ebcf9
* Some work on querying and cacheing plugin RDF from a central index
author | Chris Cannam |
---|---|
date | Fri, 17 Oct 2008 15:26:29 +0000 (2008-10-17) |
parents | abaf3d7195ce |
children | 6a94bb528e9d |
line wrap: on
line source
/* -*- 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. */ #ifndef _ZOOM_CONSTRAINT_H_ #define _ZOOM_CONSTRAINT_H_ #include <stdlib.h> /** * ZoomConstraint is a simple interface that describes a limitation on * the available zoom sizes for a view, for example based on cache * strategy or a (processing) window-size limitation. * * The default ZoomConstraint imposes no actual constraint except for * a nominal maximum. */ class ZoomConstraint { public: virtual ~ZoomConstraint() { } enum RoundingDirection { RoundDown, RoundUp, RoundNearest }; /** * Given the "ideal" block size (frames per pixel) for a given * zoom level, return the nearest viable block size for this * constraint. * * For example, if a block size of 1523 frames per pixel is * requested but the underlying model only supports value * summaries at powers-of-two block sizes, return 1024 or 2048 * depending on the rounding direction supplied. */ virtual size_t getNearestBlockSize(size_t requestedBlockSize, RoundingDirection = RoundNearest) const { if (requestedBlockSize > getMaxZoomLevel()) return getMaxZoomLevel(); else return requestedBlockSize; } /** * Return the maximum zoom level within range for this constraint. */ virtual size_t getMaxZoomLevel() const { return 262144; } }; #endif