There is no need to use sprites here, especially if it's causing problems. ResourceLoader instead lets use a separate image for each arrow, all of which will be embedded into the CSS as data URLs (in modern browsers, but there is a working fallback for older ones).

massaf wrote:

I agree that sprites made this a lot more troublesome, especially since we're drawing shadows around the guiders. I wonder if it's better to just do raw shapes and draw the shadows via CSS. I'll play around with that a little.

I discovered Guiders actually has a _arrowSize field, which we may need to update.

massaf wrote:

Fix here: https://gerrit.wikimedia.org/r/#/c/55100/

Using CSS to shape our arrows would reduce browser support, so sprites will remain for now. We can tackle _arrowSize in another bug.

Merged.