Chris@1532: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@1532: 
Chris@1532: /*
Chris@1532:     Sonic Visualiser
Chris@1532:     An audio file viewer and annotation editor.
Chris@1532:     Centre for Digital Music, Queen Mary, University of London.
Chris@1532:     
Chris@1532:     This program is free software; you can redistribute it and/or
Chris@1532:     modify it under the terms of the GNU General Public License as
Chris@1532:     published by the Free Software Foundation; either version 2 of the
Chris@1532:     License, or (at your option) any later version.  See the file
Chris@1532:     COPYING included with this distribution for more information.
Chris@1532: */
Chris@1532: 
Chris@1532: #ifndef SV_ZOOM_LEVEL_H
Chris@1532: #define SV_ZOOM_LEVEL_H
Chris@1532: 
Chris@1534: #include "BaseTypes.h"
Chris@1534: 
Chris@1532: #include <ostream>
Chris@1533: #include <cmath>
Chris@1532: 
Chris@1532: /** Display zoom level. Can be an integer number of samples per pixel,
Chris@1532:  *  or an integer number of pixels per sample.
Chris@1532:  */
Chris@1532: struct ZoomLevel {
Chris@1532: 
Chris@1532:     enum Zone {
Chris@1532:         FramesPerPixel, // zoomed out (as in classic SV)
Chris@1532:         PixelsPerFrame  // zoomed in beyond 1-1 (interpolating the waveform)
Chris@1532:     };
Chris@1533: 
Chris@1532:     Zone zone;
Chris@1532:     int level;
Chris@1532: 
Chris@1532:     ZoomLevel() : zone(FramesPerPixel), level(1) { }
Chris@1532:     ZoomLevel(Zone z, int lev) : zone(z), level(lev) { }
Chris@1532:     
Chris@1532:     bool operator<(const ZoomLevel &other) const {
Chris@1532:         if (zone == FramesPerPixel) {
Chris@1532:             if (other.zone == zone) {
Chris@1532:                 return level < other.level;
Chris@1532:             } else {
Chris@1532:                 return false;
Chris@1532:             }
Chris@1532:         } else {
Chris@1532:             if (other.zone == zone) {
Chris@1532:                 return level > other.level;
Chris@1532:             } else {
Chris@1532:                 return false;
Chris@1532:             }
Chris@1532:         }
Chris@1532:     }
Chris@1532: 
Chris@1532:     bool operator==(const ZoomLevel &other) const {
Chris@1532:         return (zone == other.zone && level == other.level);
Chris@1532:     }
Chris@1532: 
Chris@1532:     ZoomLevel incremented() const {
Chris@1532:         if (zone == FramesPerPixel) {
Chris@1532:             return { zone, level + 1 };
Chris@1532:         } else if (level == 1) {
Chris@1532:             return { FramesPerPixel, 2 };
Chris@1532:         } else if (level == 2) {
Chris@1532:             return { FramesPerPixel, 1 };
Chris@1532:         } else {
Chris@1532:             return { zone, level - 1 };
Chris@1532:         }
Chris@1532:     }
Chris@1532: 
Chris@1532:     ZoomLevel decremented() const {
Chris@1532:         if (zone == PixelsPerFrame) {
Chris@1532:             return { zone, level + 1 };
Chris@1532:         } else if (level == 1) {
Chris@1532:             return { PixelsPerFrame, 2 };
Chris@1532:         } else {
Chris@1532:             return { zone, level - 1 };
Chris@1532:         }
Chris@1532:     }
Chris@1532: 
Chris@1533:     /** Inexact conversion. The result is a whole number if we are
Chris@1533:      *  zoomed in enough (in PixelsPerFrame zone), a fraction
Chris@1533:      *  otherwise.
Chris@1533:      */
Chris@1532:     double framesToPixels(double frames) const {
Chris@1532:         if (zone == PixelsPerFrame) {
Chris@1532:             return frames * level;
Chris@1532:         } else {
Chris@1532:             return frames / level;
Chris@1532:         }
Chris@1532:     }
Chris@1532: 
Chris@1533:     /** Inexact conversion. The result is a whole number if we are
Chris@1533:      *  zoomed out enough (in FramesPerPixel zone), a fraction
Chris@1533:      *  otherwise.
Chris@1533:      */
Chris@1532:     double pixelsToFrames(double pixels) const {
Chris@1532:         if (zone == PixelsPerFrame) {
Chris@1532:             return pixels / level;
Chris@1532:         } else {
Chris@1532:             return pixels * level;
Chris@1532:         }
Chris@1532:     }
Chris@1533: 
Chris@1533:     /** Return a ZoomLevel that approximates the given ratio of pixels
Chris@1533:      *  to frames.
Chris@1533:      */
Chris@1534:     static ZoomLevel fromRatio(int pixels, sv_frame_t frames) {
Chris@1533:         if (pixels < frames) {
Chris@1534:             return { FramesPerPixel, int(round(double(frames)/pixels)) };
Chris@1533:         } else {
Chris@1534:             int r = int(round(pixels/double(frames)));
Chris@1533:             if (r > 1) {
Chris@1533:                 return { PixelsPerFrame, r };
Chris@1533:             } else {
Chris@1533:                 return { FramesPerPixel, 1 };
Chris@1533:             }
Chris@1533:         }
Chris@1533:     }
Chris@1532: };
Chris@1532: 
Chris@1532: std::ostream &operator<<(std::ostream &s, const ZoomLevel &z);
Chris@1532: 
Chris@1532: #endif