Handle zoomed canvas in canvas-applets

[marktaipan-cvisionai]

Category Bugfix

Problem Canvas applets use the getPNGData() method from annotation.js. However, canvas applets assume that this returns the whole image, but it provides what's visible on the canvas. If the user is zoomed in, only this zoomed in portion of the image is shown and will break the current canvas-applet-element assumptions.

Request At minimum the canvas applet should be given the entire image. There likely are cases where both the entire image and the zoom information should be provided to the canvas applet to mimic the current state of the annotator.