An OpenSeadragon plugin that adds fabricjs overlay capability.
Compatible with OpenSeadragon 2.1.0 or greater.
To use, include the openseadragon-fabricjs-overlay.js file after openseadragon.js on your web page.
To add fabricjs overlay capability to your OpenSeadragon Viewer, call fabricjsOverlay({scale: scaleWidth}) on it. scaleWidth is arbitrary scale for created fabric canvas. 0 corresponds to 0 and scaleWidth corresponds to 1 in OpenSeadragon viewport coordinates. This will return a new object with the following methods:
fabricCanvas(): Returns fabricjs canvas that you can add elements toresize(): If your viewer changes size, you'll need to resize the fabricjs overlay by calling this method.
See online demo or demo.html for an example of it in use.
support for multiple overlays commissioned by qikkeronline - thanks for supporting open source