NAME

HTML::Object::DOM::VideoTrackList - HTML Object DOM VideoTrackList Class

SYNOPSIS

use HTML::Object::DOM::VideoTrackList;
my $list = HTML::Object::DOM::VideoTrackList->new || 
    die( HTML::Object::DOM::VideoTrackList->error, "\n" );

VERSION

v0.2.0

DESCRIPTION

The VideoTrackList interface is used to represent a list of the video tracks contained within a <video> element, with each track represented by a separate VideoTrack object in the list.

It inherits from HTML::Object::EventTarget.

INHERITANCE

+-----------------------+     +---------------------------+     +-------------------------+     +-----------------------------------+
| HTML::Object::Element | --> | HTML::Object::EventTarget | --> | HTML::Object::DOM::List | --> | HTML::Object::DOM::VideoTrackList |
+-----------------------+     +---------------------------+     +-------------------------+     +-----------------------------------+

PROPERTIES

Inherits properties from its parent HTML::Object::DOM::List

length

The number of tracks in the list.

Example:

my $videoElem = $doc->querySelector( 'video' );
my $numVideoTracks = 0;
if( $videoElem->videoTracks )
{
    $numVideoTracks = $videoElem->videoTracks->length;
}

See also Mozilla documentation

selectedIndex

Sets or gets a number. Under perl, this is not set automatically. It is up to you to set this to whatever number you see fit.

Under JavaScript, this is the index of the currently selected track, if any, or −1 otherwise.

It returns the number as an object

See also Mozilla documentation

selectedindex

Alias for "selectedIndex"

METHODS

Inherits methods from its parent HTML::Object::DOM::List

addEventListener

Calls and returns the value from addEventListenerCalls in the ancestor class HTML::Object::DOM::List

children

Returns an array object of this element's children.

forEach

This is an alias for "foreach" in Module::Generic::Array

getTrackById

Returns the VideoTrack found within the VideoTrackList whose id matches the specified string. If no match is found, undef is returned.

Example:

my $theTrack = $VideoTrackList->getTrackById( $id );

See also Mozilla documentation

EVENTS

Events fired are of class HTML::Object::DOM::TrackEvent

addtrack

Fired when a new video track has been added to the media element. Also available via the "onaddtrack" property.

Example:

my $videoElement = $doc->querySelector('video');

$videoElement->videoTracks->addEventListener( addtrack => sub
{
    my $event = shift( @_ );
    say( "Video track: ", $event->track->label, " added" );
});

my $videoElement = $doc->querySelector('video');

$videoElement->videoTracks->onaddtrack = sub
{
    my $event = shift( @_ );
    say( "Video track: ", $event->track->label, " added" );
};

See also Mozilla documentation

change

Fired when a video track has been made active or inactive. Also available via the "onchange" property.

Example:

my $videoElement = $doc->querySelector( 'video' );
$videoElement->videoTracks->addEventListener( change => sub
{
    say( "'", $event->type, "' event fired" );
});

# changing the value of 'selected' will trigger the 'change' event
my $toggleTrackButton = $doc->querySelector( '.toggle-$track' );
$toggleTrackButton->addEventListener( click => sub
{
    my $track = $videoElement->videoTracks->[0];
    $track->selected = !$track->selected;
});

my $videoElement = $doc->querySelector( 'video' );
$videoElement->videoTracks->onchange = sub
{
    my $event = shift( @_ );
    say( "'", $event->type, "' event fired" );
};

# changing the value of 'selected' will trigger the 'change' event
my $toggleTrackButton = $doc->querySelector( '.toggle-$track' );
$toggleTrackButton->addEventListener( click => sub
{
    my $track = $videoElement->videoTracks->[0];
    $track->selected = !$track->selected;
});

See also Mozilla documentation

removetrack

Fired when a new video track has been removed from the media element. Also available via the "onremovetrack" property.

Example:

my $videoElement = $doc->querySelector( 'video' );

$videoElement->videoTracks->addEventListener( removetrack => sub
{
    my $event = shift( @_ );
    say( "Video track: ", $event->track->label, " removed" );
});

my $videoElement = $doc->querySelector( 'video' );

$videoElement->videoTracks->onremovetrack = sub
{
    my $event = shift( @_ );
    say( "Video track: ", $event->track->label, " removed" );
};

See also Mozilla documentation

EVENT HANDLERS

onaddtrack

An event handler to be called when the "addtrack" event is fired, indicating that a new video track has been added to the media element.

Example:

$doc->querySelector('video')->videoTracks->onaddtrack = sub
{
    my $event = shift( @_ );
    addToTrackList( $event->track );
};

See also Mozilla documentation

onchange

An event handler to be called when the change event occurs — that is, when the value of the selected property for a track has changed, due to the track being made active or inactive.

Example:

my $trackList = $doc->querySelector( 'video' )->videoTracks;
$trackList->onchange = sub
{
    my $event = shift( @_ );
    $trackList->forEach(sub
    {
        my $track = shift( @_ );
        updateTrackSelectedButton( $track->id, $track->selected );
    });
};

See also Mozilla documentation

onremovetrack

An event handler to call when the removetrack event is sent, indicating that a video track has been removed from the media element.

Example:

$doc->querySelector( 'my-video' )->videoTracks->onremovetrack = sub
{
    $myTrackCount = $doc->querySelector( 'my-video' )->videoTracks->length;
};

See also Mozilla documentation

AUTHOR

Jacques Deguest <jack@deguest.jp>

SEE ALSO

Mozilla documentation

COPYRIGHT & LICENSE

Copyright(c) 2021 DEGUEST Pte. Ltd.

All rights reserved

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

cpanm HTML::Object

perl -MCPAN -e shell
install HTML::Object