Re: Can someone explain this code in xterm.c?

[Richard Stallman <rms@gnu.org>]

    > It appears to me that vertical_scroll_bar_extra holds the 
    > width in pixels of the scroll bar, in all cases.  Its name is
    > misleading.

    But AFAICS it is not used for that purpose -- in the cases where it is
    used (notably in CHAR_TO_PIXEL_WIDTH), it is supposed to be the width
    of the scroll bar _area_, not the actual width of the scroll bar.

We are describing the same thing in different words.

    But I would rather go over each use (there are only a few) of
    vertical_scroll_bar_extra and change them to use the proper value of
    either FRAME_SCROLL_BAR_PIXEL_WIDTH or "scroll_bar_columns *
    canonical_x_unit".

If that works, it is ok with me.

    So when is x_set_window_size_1 activated -- e.g. as the comment on
    x_set_window_size_1 suggests, when doe emacs run under X without a
    widget?

I don't know when there's no widget if using Xt or GTK,
but x_set_window_size always calls x_set_window_size_1
when not using Xt and GTK.