ohif-viewer/Packages/viewerbase/client/components/viewer/playClipButton/playClipButton.html

<template name="playClipButton">
    <div id="{{this.id}}"
         class="toolbarSectionButton rp-x-1 {{this.classes}} {{activeClass}} {{ #if isPlaying }}active{{/if}}"
         title="{{this.title}}">
    <div class="svgContainer">
        {{ #if isPlaying }}
            <i class="fa fa-stop fa-fw"></i>
        {{ else }}
            <i class="fa fa-play fa-fw"></i>
        {{ /if }}
    </div>
        <div class="buttonLabel">
            {{ #if isPlaying }}
                Stop
            {{ else }}
                Play
            {{/if}}
        </div>
    </div>
</template>