Optional imgFor simple backgrounds, the image to use. Optional; you can also supply a url.
Optional onOptional function to call when the image has loaded (or otherwise claims to be ready)
Type of background to render.
Optional urlURL for the background. When type is set to BackgroundTypes.simple you can supply either this, or an Image. When type is set to
BackgroundTypes.tiled, you can supply this, or you can supply a urlGenerator function instead. If you supply url and no urlGenerator, the
url you supply is treated as a template for the url for any given tile, and is expected to contain {z}, {x} and {y} placeholders.
The form of the URL can be anything you like as long as it has the placeholders for z, x and y. For instance:
http://foo.com/{z}/{x}/{y} https://bar.com?zoom={z}&x={x}&y={y}
etc
Optional visibleWhether or not the background should initially be visible. Defaults to true.
Options for an image background