view base/ZoomConstraint.h @ 5:31c4ed2d5da6

* Hook up SV file i/o. You can now save and load sessions. Some problems -- gain is not reloaded correctly for waveforms, reloaded panes are not properly reconnected to the panner, and no doubt plenty of others.
author Chris Cannam
date Tue, 17 Jan 2006 17:45:55 +0000
parents d86891498eef
children f67ddc287bc3
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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.
 */

class ZoomConstraint
{
public:
    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
    {
	return requestedBlockSize;
    }
};

#endif