Hm. Is it technically possible to use a walkable area that is just 1 pixel wide line?
(Thing like that is needed, for example - for character walking on a rope or a narrow log over the chasm)
I tried and couldn't. Width of 2 pixels worked fine.
Well I think for safety, walkable areas as well as non-walkable areas are better kept 2 pixels+ wide. Because the character may move more than 1 pixel displacement per game loop, so he may not walk properly in a thin walkable area or walk past some nonwalkable areas that he shouldn't, which is the same problem in the pre-walkable area era (the glorious AC walls era).
im using some very narrow walkable areas, they can occasionaly cause the character view to glitch slightly..this might depend on wether the walkable area is a straight line ;ie all the pixels line up, if it looks like a flight of stairs, because it's going diagonaly across the screen then that would make certain parts of the area even less than one pixel across , and cause problems ?
AGS uses varying granularities for its path calculations, depending on the size of the walkable area - to ensure it always works, your walkable areas should always be at least 3 pixels wide.