view base/ZoomLevel.h @ 1671:82d03c9661f9 single-point

Rework isReady()/getCompletion() on models. Previously the new overhauled models were implementing getCompletion() but inheriting a version of isReady() (from the Model base) that didn't call it, referring only to isOK(). So they were reporting completion as soon as they had begun. Instead hoist getCompletion() to abstract base and call it from Model::isReady().

/* -*- 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