Simple image projection in vanilla Javascript. See the demo.

Whenever the surface is hovered, the viewfinder and the projection show up. Everything covered by the viewfinder is shown as the projection.

Package is hosted in github https://github.com/widatama/js-imageprojection/pkgs/npm/js-imageprojection

Create a div with an img inside it. This div will be the container and the img will be used as the image for the surface. The url for projection image is also needed, in this example it is provided as a data attribute in the div.

<div class="wrap" data-projection-image-url="images/sample.jpg">
  <img src="images/sample-halved.jpg"/>
</div>

The HTML elements will need to be styled, here is an example of how to do it. The class prefix ip- can be changed with javascript.

In general, the viewfinder and projection have to be shown when --visible class is applied. The projection position also have to be set if it is not set with Javascript.

.ip-surface {
  position: absolute;
  z-index: 2;

  display: block;

  width: 100%;
  height: 100%;
}

.ip-viewfinder {
  background: rgba(255,255,255,.5);

  position: absolute;
  z-index: 3;

  transition: opacity .2s ease-in-out;

  opacity: 0;
  border: dotted #CCCCCC 1px;
}

.ip-viewfinder--visible {
  opacity: 1;
}

.ip-projection {
  position: absolute;
  z-index: 3;
  left: 600px;
  top: 0;

  transition: opacity .2s ease-in-out;

  opacity: 0;
}

.ip-projection--visible {
  opacity: 1;
}

Import the Container and create an instance of it. Available options are

• classPrefix default: ip-. Set HTML element class prefix
• projectionImageUrl. The url for image that will be shown in the projection
• projectionPosition. The left and top value of projection HTML element. This can also be set with CSS.

import { Container } from 'js-imageprojection';

const run = () => {
    const $container = document.querySelector('.wrap');
    new Container($container, { projectionImageUrl: $container.dataset.projectionImageUrl });
};

document.addEventListener('DOMContentLoaded', run);

Install dependencies

npm install

This will run a preview server at localhost:9999. Everything that is served by the dev server is inside preview directory.

npm start

This will create a Javascript bundle in dist directory.

npm run build

This will run the tests.

npm test