Luc Teirlinck <teirllm@dms.auburn.edu> writes:
> After taking a closer look at your patch, I guess one would have to be
> careful that there are no functions calling the functions you changed
> that _already_ adjust for FRAME_INTERNAL_BORDER_WIDTH, in which case
> they will double-adjust after the patch.  I did not find any, but I
> have not looked that carefully.

I did a grep in the source tree, and it seems these macros are not
used anywhere else in Emacs, except for one small reference in
Fwindow_vscroll:

FRAME_PIXEL_X_FROM_CANON_X:
	src/window.c:788: Fcoordinates_in_window_p
	src/window.c:943: Fwindow_at

FRAME_PIXEL_Y_FROM_CANON_Y:
        src/window.c:789: Fcoordinates_in_window_p
        src/window.c:944: Fwindow_at

FRAME_CANON_X_FROM_PIXEL_X:
	src/window.c:799: Fcoordinates_in_window_p

FRAME_CANON_Y_FROM_PIXEL_Y:
	src/window.c:800: Fcoordinates_in_window_p
	src/window.c:6167: Fwindow_vscroll

Unfortunately, `window-vscroll' doesn't like my patch:

	(set-frame-parameter nil 'internal-border-width 20)
	(set-window-vscroll nil 0.2) ==> -1.13, should be around 0.2
	(window-vscroll) ==> -1.13, should be around 0.2

> I guess an alternative would be to make the adjustment inside
> `window-at' and `coordinates-in-window-p'.

I think it's easier to adjust the pixel coordinates right inside
coordinates_in_window_p, which both functions use: