satie/src/private_metre_metreDurations.ts

A sheet music renderer for the web

/**
 * This file is part of Satie music engraver <https://github.com/jnetterf/satie>.
 * Copyright (C) Joshua Netterfield <joshua.ca> 2015 - present.
 * 
 * Satie is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * Satie is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 * 
 * You should have received a copy of the GNU Affero General Public License
 * along with Satie.  If not, see <http://www.gnu.org/licenses/>.
 */

import {times} from "lodash";
import * as invariant from "invariant";
import {TimeModification, Time} from "musicxml-interfaces";

import {IChord, divisions} from "./private_chordUtil";

/** 
 * Information needed to create a duration using makeDuration().
 * 
 * See IChord and makeDuration().
 */
export interface ITimeSpec {
    /** 
     * The base of the note, as encoded by Lilypond.
     * 
     * A quarter note is '4', a half note is '8', ...
     */
    count: number;

    /** 
     * The number of displayed dots, or null.
     */
    dots?: number;

    /** 
     * The time modification (canonical tuplet), or null.
     */
    timeModification?: TimeModification;
}

/** 
 * Creates a simple realization of an IChord
 * 
 * @param spec
 */
function _makeDuration(spec: ITimeSpec): IChord {
    invariant(!spec.timeModification, "timeModification is not implemented in makeDuration");
    return [{
        dots: times(spec.dots || 0, () => { return {}; }),
        noteType: {
            duration: spec.count
        },
        _class: "Note",
    }];
}

export function makeDuration(divPerQuarter: number, time: Time, divisionsInDuration: number): IChord {
    for (let count = 1; count <= 512; ++count) {
        for (let dots = 0; dots < 3; ++dots) {
            const spec = {count, dots};
            if (divisions(spec, {time, divisions: divPerQuarter}, true) === divisionsInDuration) {
                return _makeDuration(spec);
            }
        }
    }
    throw new Error(`Unknown duration ${divisionsInDuration} at ` +
        `${divPerQuarter} divs per quarter`);
}

export const _512 = _makeDuration({ count: 512 });
export const _256 = _makeDuration({ count: 256 });
export const _256D = _makeDuration({ count: 256, dots: 1 });
export const _128 = _makeDuration({ count: 128 });
export const _128D = _makeDuration({ count: 128, dots: 1 });
export const _64 = _makeDuration({ count: 64 });
export const _64D = _makeDuration({ count: 64, dots: 1 });
export const _32 = _makeDuration({ count: 32 });
export const _32D = _makeDuration({ count: 32, dots: 1 });
export const _16 = _makeDuration({ count: 16 });
export const _16D = _makeDuration({ count: 16, dots: 1 });
export const _16DD = _makeDuration({ count: 16, dots: 2 });
export const _8 = _makeDuration({ count: 8 });
export const _8D = _makeDuration({ count: 8, dots: 1 });
export const _8DD = _makeDuration({ count: 8, dots: 2 });
export const _4 = _makeDuration({ count: 4 });
export const _4D = _makeDuration({ count: 4, dots: 1 });
export const _4DD = _makeDuration({ count: 4, dots: 2 });
export const _2 = _makeDuration({ count: 2 });
export const _2D = _makeDuration({ count: 2, dots: 1 });
export const _2DD = _makeDuration({ count: 2, dots: 2 });
export const _1 = _makeDuration({ count: 1 });
export const _1D = _makeDuration({ count: 1, dots: 1 });
export const _1DD = _makeDuration({ count: 1, dots: 2 });
export const _05 = _makeDuration({ count: 1 / 2 });