Useful component that works well, however the JS in it must be updated to the latest version from the source https://html2canvas.hertzen.com.
I made it work properly with the version: html2canvas 1.4.1 only (used the html2canvas.min.js).
I was able to add some variables to control size and resolution of the resulting image.
In some cases it proved best to render the desired container to a plain fully flexible page and export it out of that. Play with WindowWidth and Scale parameters to obtain desired png resolution. In my cases I used WindowWidth = 1000/1500/2000 and Scale = 1.5/2 to get sufficient resolution.