Mercurial > hg > svcore
diff base/ZoomLevel.h @ 1551:4de4284d0596
Merge from branch zoom
author | Chris Cannam |
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date | Wed, 10 Oct 2018 08:44:15 +0100 |
parents | 8f9e9cff141d |
children | 1ae6a19464a7 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/base/ZoomLevel.h Wed Oct 10 08:44:15 2018 +0100 @@ -0,0 +1,124 @@ +/* -*- 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 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 SV_ZOOM_LEVEL_H +#define SV_ZOOM_LEVEL_H + +#include "BaseTypes.h" + +#include <ostream> +#include <cmath> + +/** Display zoom level. Can be an integer number of samples per pixel, + * or an integer number of pixels per sample. + */ +struct ZoomLevel { + + enum Zone { + FramesPerPixel, // zoomed out (as in classic SV) + PixelsPerFrame // zoomed in beyond 1-1 (interpolating the waveform) + }; + + Zone zone; + int level; + + ZoomLevel() : zone(FramesPerPixel), level(1) { } + ZoomLevel(Zone z, int lev) : zone(z), level(lev) { } + + bool operator<(const ZoomLevel &other) const { + if (zone == FramesPerPixel) { + if (other.zone == zone) { + return level < other.level; + } else { + return false; + } + } else { + if (other.zone == zone) { + return level > other.level; + } else { + return false; + } + } + } + + bool operator==(const ZoomLevel &other) const { + return (zone == other.zone && level == other.level); + } + + ZoomLevel incremented() const { + if (zone == FramesPerPixel) { + return { zone, level + 1 }; + } else if (level == 1) { + return { FramesPerPixel, 2 }; + } else if (level == 2) { + return { FramesPerPixel, 1 }; + } else { + return { zone, level - 1 }; + } + } + + ZoomLevel decremented() const { + if (zone == PixelsPerFrame) { + return { zone, level + 1 }; + } else if (level == 1) { + return { PixelsPerFrame, 2 }; + } else { + return { zone, level - 1 }; + } + } + + /** Inexact conversion. The result is a whole number if we are + * zoomed in enough (in PixelsPerFrame zone), a fraction + * otherwise. + */ + double framesToPixels(double frames) const { + if (zone == PixelsPerFrame) { + return frames * level; + } else { + return frames / level; + } + } + + /** Inexact conversion. The result is a whole number if we are + * zoomed out enough (in FramesPerPixel zone), a fraction + * otherwise. + */ + double pixelsToFrames(double pixels) const { + if (zone == PixelsPerFrame) { + return pixels / level; + } else { + return pixels * level; + } + } + + /** Return a ZoomLevel that approximates the given ratio of pixels + * to frames. + */ + static ZoomLevel fromRatio(int pixels, sv_frame_t frames) { + if (pixels < frames) { + return { FramesPerPixel, int(round(double(frames)/pixels)) }; + } else { + int r = int(round(pixels/double(frames))); + if (r > 1) { + return { PixelsPerFrame, r }; + } else { + return { FramesPerPixel, 1 }; + } + } + } +}; + +std::ostream &operator<<(std::ostream &s, const ZoomLevel &z); + +#endif