On Mon, Feb 24, 2014 at 8:41 AM, martin rudalics <rudalics@gmx.at> wrote:
> If possible, I would like to see the pixel width of fringes + scroll bar to
> be a multiple of the width of the font used in the frame, since it is much
> more convenient for elisp packages that make layout decisions. (As I
> mentioned above, now they are 5 characters and one pixel. In 24.3 they were
> exactly six characters wide.)

The pixel widths of fringes and scrollbars are customizable on a per
frame/window basis so you should be able to set them up on you system
as you need.  Does that fail?

Well, it's much more work to handle things on the pixel level than working with characters as the base unit.

For example, I'm currently writing a package to set up multiple side-by-size windows. When figuring out a suitable frame width, I used to multiply the number of side-by-side windows with the sum of the column width and the width (in characters) of the fringe and scroll bars, to get the number of characters to set the width to. Now, I would have to work on the pixel level to do this properly -- this is much more error prone and I can't use the code on old Emacs versions.

It doesn't help that functions doesn't seem to be designed to work together, for example I would expect:
    (set-frame-size (selected-frame) (frame-pixel-width) (frame-pixel-height) t)'
to be a no-op, but instead the frame increases its size both on the width and on the height.

Another argument of not having a "odd" width is that when splitting windows side-by-side, you will end up with an unused gap to the right of almost a full character. Steps to repeat:

    emacs -Q
    (setq truncate-partial-width-windows nil) C-j
    C-x 3

        Here, the right window have an unused space between the rightmost character and the fringe, the space is almost a character wide. It's not possible to resize the frame manually to correct this, as the frame can only be resized full characters (as it should be). (When `truncate-partial-width-windows' is t, the gap is used to display a partial character.)

To conclude, I would be much happier if the sum of the fringes and the scroll bar would be an even five characters rather than five characters and one pixel, as it is today.

The question is if this is due to some display bug (maybe OS X specific) or if this is the way it is supposed to work now?

    -- Anders