Coordinates and Windows

[martin rudalics <rudalics@gmx.at>]

Section 27.24 of the Elisp manual contains the following description:


Coordinates and Windows

This section describes functions that report the position of a window.
Most of these functions report positions relative to the window's
frame.  In this case, the coordinate origin `(0,0)' lies near the upper
left corner of the frame.  For technical reasons, on graphical displays
the origin is not located at the exact corner of the graphical window
as it appears on the screen.  If Emacs is built with the GTK+ toolkit,
the origin is at the upper left corner of the frame area used for
displaying Emacs windows, below the title-bar, GTK+ menu bar, and tool
bar (since these are drawn by the window manager and/or GTK+, not by
Emacs).  But if Emacs is not built with GTK+, the origin is at the
upper left corner of the tool bar (since in this case Emacs itself
draws the tool bar).  In both cases, the X and Y coordinates increase
rightward and downward respectively.


My intention is to remove this difference and make the "coordinate
origin" for all systems the top/left corner of the root window of the
respective frame.  Practically, this is what the GTK+ build does now.

I'm not yet sure whether this is feasible and whether there will be any
difficulties.  Anyway, if you see problems or have any objections please
tell me now.

Thanks, martin