satie/src/document_measure.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 {flatten, map, values, filter} from "lodash";
import * as invariant from "invariant";

import {IModel} from "./document";

export interface ISegment extends Array<IModel> {
    owner: number;
    ownerType: "staff" | "voice";
    divisions: number;
    part?: string;
}

export interface IMeasurePart {
    voices: ISegment[];
    staves: ISegment[];
}

/**
 * Based on MusicXML's Measure, but with additional information, and with a staff/voice-seperated and
 * monotonic parts element.
 */
export interface IMeasure {
    idx: number; // 0-indexed, can change
    uuid: number;
    number: string; // 1-indexed
    implicit?: boolean;
    width?: number;
    nonControlling?: boolean;
    parts: {
        [id: string]: IMeasurePart;
    };

    /**
     * Incremented whenever anything in the measure changes.
     * Local only and monotonic.
     */
    version: number;
};

export function getMeasureSegments(measure: IMeasure): ISegment[] {
    let voiceSegments = <ISegment[]> flatten(map(values<IMeasurePart>(measure.parts),
        part => part.voices));

    let staffSegments = <ISegment[]> flatten(map(values<IMeasurePart>(measure.parts),
        part => part.staves));

    return filter(voiceSegments.concat(staffSegments), s => !!s);
}

export function reduceToShortestInSegments(shortest: number, segment: ISegment) {
    return segment.reduce(reduceToShortestInSegment, shortest);
}

export function reduceToShortestInSegment(shortest: number, model: IModel) {
    if (!(model.divCount >= 0)) {
        invariant(model.divCount >= 0, "Counts must exceed 0 in", model);
    }
    let divCount = model && model.divCount ? model.divCount : Number.MAX_VALUE;
    return Math.min(shortest, divCount);
}