How to write a Front plugin ?¶

The hooks used in front plugin are:

• addHTML: add some html at the end of the presentation
• addHTMLFromFiles: an array of html files to append in the body
• addScripts: an array of ressources to load (will be convert to script tag with src value as each entry)
• addScriptModules: an array of ressources to load as modules (will be convert to script tag with src value as each entry and type="module")
• addSpeakerScripts: an array of ressources to load (will be convert to script tag with src value as each entry) but on speaker view
• addStyles: an array of ressources to load (will be convert to link tag with href value as each entry)
• addSpeakerStyles: an array of ressources to load (will be convert to link tag with href value as each entry) but on speaker view
• onSlideChange: javascript code which will be executed after a slide is changed
• onSpeakerViewSlideChange: javascript code which will be executed after a slide is changed

Creation of a Webcam plugin¶

First, create a directory plugins/webcam in your talk repository

Consider the following plugin.json:

{
  "addStyles": ["./plugins/webcam/webcam.css"],
  "addScripts": ["./plugins/webcam/webcam.js"]
}

In the webcam.js, we will code the connexion to the webcam and the display:

const video = document.querySelector("#webcam");

async function getConnectedDevices(type) {
  const devices = await navigator.mediaDevices.enumerateDevices();
  return devices.filter((device) => device.kind === type);
}

async function openCamera(cameraId, minWidth, minHeight) {
  const constraints = {
    video: {
      deviceId: cameraId,
      width: { min: minWidth },
      height: { min: minHeight },
    },
  };

  return await navigator.mediaDevices.getUserMedia(constraints);
}

const webcamize = async () => {
  const cameras = await getConnectedDevices("videoinput");
  if (cameras && cameras.length > 0) {
    cameras.forEach((camera) => {
      console.log(camera, window.slidesk.env.WEBCAM);
      if (camera.label.includes(window.slidesk.env.WEBCAM)) {
        console.log("camera found");
        openCamera(camera.deviceId, 1280, 720).then(
          (stream) => (video.srcObject = stream)
        );
      }
    });
  }
};

webcamize();

Then in the slide, you can add <video autoplay="true" id="webcam"></video> where you want the webcam.