view base/ZoomConstraint.h @ 115:90ade4fa63be

* Fix serious failure to reload "imported" (i.e. all non-derived non-main)
  models from .sv file
* Give a short playback duration to notes with formal duration of 0 or 1
* Show crosshairs on spectrogram even when there is another layer on top
  (if it isn't opaque)
* Always paste to the same time in the layer as the cut/copy was from, rather
  than to the playback pointer -- less flexible, but more predictable and
  less annoying.  We probably need a way to get the old behaviour if pasting
  from somewhere else in the future (e.g. from a text file), but we can't do
  that yet anyway
* Use a compound operation for dragging and resizing selections, so as to
  ensure a single undo operation works
* Use a note model as the target for feature extraction plugins that output
  variable samplerate data with more than one value per feature
* Avoid possible crashes in cut/paste if a layer proves to have no model

/* -*- 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;
    }

    virtual size_t getMaxZoomLevel() const { return 262144; }
};

#endif