Mercurial > hg > svcore
annotate base/ZoomConstraint.h @ 12:f67ddc287bc3
* Add ability to create empty layers for editing
* Add first basic editing capability (adding points to a time instant layer)
* Add various keyboard and mouse shortcuts for navigation &c
* Add ability to resize a selection by dragging its edges
* Add maximum zoom level
author | Chris Cannam |
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date | Thu, 26 Jan 2006 16:15:40 +0000 |
parents | d86891498eef |
children | 070e9e1e40ea |
rev | line source |
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Chris@0 | 1 /* -*- c-basic-offset: 4 -*- vi:set ts=8 sts=4 sw=4: */ |
Chris@0 | 2 |
Chris@0 | 3 /* |
Chris@0 | 4 A waveform viewer and audio annotation editor. |
Chris@2 | 5 Chris Cannam, Queen Mary University of London, 2005-2006 |
Chris@0 | 6 |
Chris@0 | 7 This is experimental software. Not for distribution. |
Chris@0 | 8 */ |
Chris@0 | 9 |
Chris@0 | 10 #ifndef _ZOOM_CONSTRAINT_H_ |
Chris@0 | 11 #define _ZOOM_CONSTRAINT_H_ |
Chris@0 | 12 |
Chris@0 | 13 #include <stdlib.h> |
Chris@0 | 14 |
Chris@0 | 15 /** |
Chris@0 | 16 * ZoomConstraint is a simple interface that describes a limitation on |
Chris@0 | 17 * the available zoom sizes for a view, for example based on cache |
Chris@0 | 18 * strategy or a (processing) window-size limitation. |
Chris@0 | 19 * |
Chris@12 | 20 * The default ZoomConstraint imposes no actual constraint except for |
Chris@12 | 21 * a nominal maximum. |
Chris@0 | 22 */ |
Chris@0 | 23 |
Chris@0 | 24 class ZoomConstraint |
Chris@0 | 25 { |
Chris@0 | 26 public: |
Chris@0 | 27 enum RoundingDirection { |
Chris@0 | 28 RoundDown, |
Chris@0 | 29 RoundUp, |
Chris@0 | 30 RoundNearest |
Chris@0 | 31 }; |
Chris@0 | 32 |
Chris@0 | 33 /** |
Chris@0 | 34 * Given the "ideal" block size (frames per pixel) for a given |
Chris@0 | 35 * zoom level, return the nearest viable block size for this |
Chris@0 | 36 * constraint. |
Chris@0 | 37 * |
Chris@0 | 38 * For example, if a block size of 1523 frames per pixel is |
Chris@0 | 39 * requested but the underlying model only supports value |
Chris@0 | 40 * summaries at powers-of-two block sizes, return 1024 or 2048 |
Chris@0 | 41 * depending on the rounding direction supplied. |
Chris@0 | 42 */ |
Chris@0 | 43 virtual size_t getNearestBlockSize(size_t requestedBlockSize, |
Chris@0 | 44 RoundingDirection = RoundNearest) |
Chris@0 | 45 const |
Chris@0 | 46 { |
Chris@12 | 47 if (requestedBlockSize > getMaxZoomLevel()) return getMaxZoomLevel(); |
Chris@12 | 48 else return requestedBlockSize; |
Chris@0 | 49 } |
Chris@12 | 50 |
Chris@12 | 51 virtual size_t getMaxZoomLevel() const { return 262144; } |
Chris@0 | 52 }; |
Chris@0 | 53 |
Chris@0 | 54 #endif |
Chris@0 | 55 |