User wants the tile texture mirrored across the NS axis only
(no 180 rotation). drawImage with width=-TILE, height=+TILE
flips only the X axis:
- Image top (north) stays at canvas top
- Image bottom (south) stays at canvas bottom
- Image left (west) -> canvas right
- Image right (east) -> canvas left
Labels N/S moved to match the new (un-Y-flipped) orientation:
N at canvas top, S at canvas bottom. The tile arrangement in
the corridor is unchanged.
Richard Zink
acac6dccfc