lbajardsilogic@0: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
lbajardsilogic@0: 
lbajardsilogic@0: /*
lbajardsilogic@0:     Sonic Visualiser
lbajardsilogic@0:     An audio file viewer and annotation editor.
lbajardsilogic@0:     Centre for Digital Music, Queen Mary, University of London.
lbajardsilogic@0:     This file copyright 2006 Chris Cannam.
lbajardsilogic@0:     
lbajardsilogic@0:     This program is free software; you can redistribute it and/or
lbajardsilogic@0:     modify it under the terms of the GNU General Public License as
lbajardsilogic@0:     published by the Free Software Foundation; either version 2 of the
lbajardsilogic@0:     License, or (at your option) any later version.  See the file
lbajardsilogic@0:     COPYING included with this distribution for more information.
lbajardsilogic@0: */
lbajardsilogic@0: 
lbajardsilogic@0: #ifndef _ZOOM_CONSTRAINT_H_
lbajardsilogic@0: #define _ZOOM_CONSTRAINT_H_
lbajardsilogic@0: 
lbajardsilogic@0: #include <stdlib.h>
lbajardsilogic@0: 
lbajardsilogic@0: /**
lbajardsilogic@0:  * ZoomConstraint is a simple interface that describes a limitation on
lbajardsilogic@0:  * the available zoom sizes for a view, for example based on cache
lbajardsilogic@0:  * strategy or a (processing) window-size limitation.
lbajardsilogic@0:  *
lbajardsilogic@0:  * The default ZoomConstraint imposes no actual constraint except for
lbajardsilogic@0:  * a nominal maximum.
lbajardsilogic@0:  */
lbajardsilogic@0: 
lbajardsilogic@0: class ZoomConstraint
lbajardsilogic@0: {
lbajardsilogic@0: public:
lbajardsilogic@0:     virtual ~ZoomConstraint() { }
lbajardsilogic@0: 
lbajardsilogic@0:     enum RoundingDirection {
lbajardsilogic@0: 	RoundDown,
lbajardsilogic@0: 	RoundUp,
lbajardsilogic@0: 	RoundNearest
lbajardsilogic@0:     };
lbajardsilogic@0: 
lbajardsilogic@0:     /**
lbajardsilogic@0:      * Given the "ideal" block size (frames per pixel) for a given
lbajardsilogic@0:      * zoom level, return the nearest viable block size for this
lbajardsilogic@0:      * constraint.
lbajardsilogic@0:      *
lbajardsilogic@0:      * For example, if a block size of 1523 frames per pixel is
lbajardsilogic@0:      * requested but the underlying model only supports value
lbajardsilogic@0:      * summaries at powers-of-two block sizes, return 1024 or 2048
lbajardsilogic@0:      * depending on the rounding direction supplied.
lbajardsilogic@0:      */
lbajardsilogic@0:     virtual size_t getNearestBlockSize(size_t requestedBlockSize,
lbajardsilogic@0: 				       RoundingDirection = RoundNearest)
lbajardsilogic@0: 	const
lbajardsilogic@0:     {
lbajardsilogic@0: 	if (requestedBlockSize > getMaxZoomLevel()) return getMaxZoomLevel();
lbajardsilogic@0: 	else return requestedBlockSize;
lbajardsilogic@0:     }
lbajardsilogic@0: 
lbajardsilogic@0:     /**
lbajardsilogic@0:      * Return the maximum zoom level within range for this constraint.
lbajardsilogic@0:      */
lbajardsilogic@0:     virtual size_t getMaxZoomLevel() const { return 262144; }
lbajardsilogic@0: };
lbajardsilogic@0: 
lbajardsilogic@0: #endif
lbajardsilogic@0: