Mercurial > hg > svcore
view base/ZoomConstraint.h @ 42:7bf163161b88
* more MainWindow/Document stuff
author | Chris Cannam |
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date | Wed, 08 Mar 2006 17:47:58 +0000 |
parents | 070e9e1e40ea |
children | 39ae3dee27b9 |
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/* -*- c-basic-offset: 4 -*- vi:set ts=8 sts=4 sw=4: */ /* A waveform viewer and audio annotation editor. Chris Cannam, Queen Mary University of London, 2005-2006 This is experimental software. Not for distribution. */ #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; } virtual size_t getMaxZoomLevel() const { return 262144; } }; #endif