When we remove the background from a glyph, we can keep track of if we made all the pixels fully transparent. If we did, we can just skip future calls to _drawFromCache, since it would be a noop anyways.
When we remove the background from a glyph, we can keep track of if we made all the pixels fully transparent. If we did, we can just skip future calls to _drawFromCache, since it would be a noop anyways.