Timeline Notches Feature Example

How to Override Timeline Formatting

/**
 * Use formatTimeCallback to style the notch labels as you wish, such
 * as with more detail as the number of pixels per second increases.
 *
 * Here we format as M:SS.frac, with M suppressed for times < 1 minute,
 * and frac having 0, 1, or 2 digits as the zoom increases.
 *
 * Note that if you override the default function, you'll almost
 * certainly want to override timeInterval, primaryLabelInterval and/or
 * secondaryLabelInterval so they all work together.
 *
 * @param: seconds
 * @param: pxPerSec
 */
function formatTimeCallback(seconds, pxPerSec) {
    seconds = Number(seconds);
    var minutes = Math.floor(seconds / 60);
    seconds = seconds % 60;

    // fill up seconds with zeroes
    var secondsStr = Math.round(seconds).toString();
    if (pxPerSec >= 25 * 10) {
        secondsStr = seconds.toFixed(2);
    } else if (pxPerSec >= 25 * 1) {
        secondsStr = seconds.toFixed(1);
    }

    if (minutes > 0) {
        if (seconds < 10) {
            secondsStr = '0' + secondsStr;
        }
        return `${minutes}:${secondsStr}`;
    }
    return secondsStr;
}

/**
 * Use timeInterval to set the period between notches, in seconds,
 * adding notches as the number of pixels per second increases.
 *
 * Note that if you override the default function, you'll almost
 * certainly want to override formatTimeCallback, primaryLabelInterval
 * and/or secondaryLabelInterval so they all work together.
 *
 * @param: pxPerSec
 */
function timeInterval(pxPerSec) {
    var retval = 1;
    if (pxPerSec >= 25 * 100) {
        retval = 0.01;
    } else if (pxPerSec >= 25 * 40) {
        retval = 0.025;
    } else if (pxPerSec >= 25 * 10) {
        retval = 0.1;
    } else if (pxPerSec >= 25 * 4) {
        retval = 0.25;
    } else if (pxPerSec >= 25) {
        retval = 1;
    } else if (pxPerSec * 5 >= 25) {
        retval = 5;
    } else if (pxPerSec * 15 >= 25) {
        retval = 15;
    } else {
        retval = Math.ceil(0.5 / pxPerSec) * 60;
    }
    return retval;
}

/**
 * Return the cadence of notches that get labels in the primary color.
 * EG, return 2 if every 2nd notch should be labeled,
 * return 10 if every 10th notch should be labeled, etc.
 *
 * Note that if you override the default function, you'll almost
 * certainly want to override formatTimeCallback, primaryLabelInterval
 * and/or secondaryLabelInterval so they all work together.
 *
 * @param pxPerSec
 */
function primaryLabelInterval(pxPerSec) {
    var retval = 1;
    if (pxPerSec >= 25 * 100) {
        retval = 10;
    } else if (pxPerSec >= 25 * 40) {
        retval = 4;
    } else if (pxPerSec >= 25 * 10) {
        retval = 10;
    } else if (pxPerSec >= 25 * 4) {
        retval = 4;
    } else if (pxPerSec >= 25) {
        retval = 1;
    } else if (pxPerSec * 5 >= 25) {
        retval = 5;
    } else if (pxPerSec * 15 >= 25) {
        retval = 15;
    } else {
        retval = Math.ceil(0.5 / pxPerSec) * 60;
    }
    return retval;
}

/**
 * Return the cadence of notches to get labels in the secondary color.
 * EG, return 2 if every 2nd notch should be labeled,
 * return 10 if every 10th notch should be labeled, etc.
 *
 * Secondary labels are drawn after primary labels, so if
 * you want to have labels every 10 seconds and another color labels
 * every 60 seconds, the 60 second labels should be the secondaries.
 *
 * Note that if you override the default function, you'll almost
 * certainly want to override formatTimeCallback, primaryLabelInterval
 * and/or secondaryLabelInterval so they all work together.
 *
 * @param pxPerSec
 */
function secondaryLabelInterval(pxPerSec) {
    // draw one every 10s as an example
    return Math.floor(10 / timeInterval(pxPerSec));
}

var wavesurfer = WaveSurfer.create({
    // your other options here
    plugins: [
        WaveSurfer.timeline.create({
            container: '#timeline',
            formatTimeCallback: formatTimeCallback,
            timeInterval: timeInterval,
            primaryLabelInterval: primaryLabelInterval,
            secondaryLabelInterval: secondaryLabelInterval,
            primaryColor: 'blue',
            secondaryColor: 'red',
            primaryFontColor: 'blue',
            secondaryFontColor: 'red'
        })
	]
});

wavesurfer.load('../media/demo.wav');