[Feat] progressive Bitmap rendering

[charlieforward9]

Target Use Case

Migrating from Leaflet to Maplibre and DeckGL has come with a plethora of advantages.

However, one of the disadvantages comes with rendering 100mb png images.

In Leaflet, when an image layer is loaded, it will paint it out from the top to the bottom as it is loaded in over the network.

Unfortunately, this is not the behavior of the BitmapLayer in DeckGL. The layer is not shown at all until the full image is loaded in, which can take anywhere from a few seconds, to many minutes, depending on the network.

Proposal

This may actually be a part of the loaders API, but having a way to progressively load images will make it much more self-explanatory that something is happening and the user needs to wait, rather than writing some custom loading indicator for the image layer.

[charlieforward9]

This is a lower priority item for our team in the long term as we plan to migrate all of our imagery to a tile server , but until we manage to execute that, it would be nice to have the Leaflet-like behavior with the images and see the BitmapLayer/ImageLoader API boost its capabilities