When drawing on the map using commands such as drawRectangle, it does not appear possible to configure compositing in the same manner as is possible in JavaScript (https://developer.mozilla.org/en/docs/Web/Guide/HTML/Canvas_tutorial/Compositing).

Currently, if I draw two partially transparent rectangles overlapping one another, the overlap of the two rectangles is visible. It would be preferable for such an overlap to not be apparent, creating the impression of one continuous shape. Is this possible? If not, it would be very useful for certain commands to be introduced to make compositing configuration possible.