In many games, there's a visually standardized way to highlight objects in a game world: Drawing an outline around them. Current CSS outline property draws an outline around the elements rectangle, but we need outlines around the transparent edges of the element. This is probably easy when native hitmaps are implemented, and a very useful feature to many web developers, not just targeted at games.

This is already possible using shadows in canvas, so there is at least a fast work-around.