User clarified: the X-swap should be in the ARRANGEMENT (east
tiles on screen right), NOT in the image (so map content is
readable). Previous attempts had it the other way around.
Combined state:
- canvasX = -perp + ... (X-swap): east (1102) on screen right,
west (1098) on screen left. x increases left to right.
- drawImage with positive width: no image X-flip. Map content
reads normally, place names not mirrored.
- Labels in normal orientation.
So the X mirror is in the corridor arrangement, not in the
satellite image content. The user can read the map normally.
Richard Zink
e4170bee62