Because the huge map image hasn't loaded before the canvas starts drawing, the image element (and therefore the canvas) doesn't occupy the size it eventually will, and once it completes the canvas gets stretched out.
Only happens when the map image isn't cached.
It does however always happen when expanding the map, since the canvas is then also expanded. You could re-draw the mines at this point but hmmm
Because the huge map image hasn't loaded before the canvas starts drawing, the image element (and therefore the canvas) doesn't occupy the size it eventually will, and once it completes the canvas gets stretched out.
Only happens when the map image isn't cached.
It does however always happen when expanding the map, since the canvas is then also expanded. You could re-draw the mines at this point but hmmm