27.10.1 Geometry Resources

To make the default size of all Emacs frames be 80 columns by 55 lines, do this:

Emacs*EmacsFrame.geometry: 80x55

To set the geometry of a particular frame named ‘fred’, do this:

Emacs*fred.geometry: 80x55

Important! Do not use the following syntax:

Emacs*geometry: 80x55

You should never use *geometry with any X application. It does not say "make the geometry of Emacs be 80 columns by 55 lines." It really says, "make Emacs and all subwindows thereof be 80x55 in whatever units they care to measure in." In particular, that is both telling the Emacs text pane to be 80x55 in characters, and telling the menubar pane to be 80x55 pixels, which is surely not what you want.

As a special case, this geometry specification also works (and sets the default size of all Emacs frames to 80 columns by 55 lines):

Emacs.geometry: 80x55

since that is the syntax used with most other applications (since most other applications have only one top-level window, unlike Emacs). In general, however, the top-level shell (the unmapped ApplicationShell widget named ‘Emacs’ that is the parent of the shell widgets that actually manage the individual frames) does not have any interesting resources on it, and you should set the resources on the frames instead.

The -geometry command-line argument sets only the geometry of the initial frame created by Emacs.

A more complete explanation of geometry-handling is

• The -geometry command-line option sets the Emacs.geometry resource, that is, the geometry of the ApplicationShell.
• For the first frame created, the size of the frame is taken from the ApplicationShell if it is specified, otherwise from the geometry of the frame.
• For subsequent frames, the order is reversed: First the frame, and then the ApplicationShell.
• For the first frame created, the position of the frame is taken from the ApplicationShell (Emacs.geometry) if it is specified, otherwise from the geometry of the frame.
• For subsequent frames, the position is taken only from the frame, and never from the ApplicationShell.

This is rather complicated, but it does seem to provide the most intuitive behavior with respect to the default sizes and positions of frames created in various ways.