28.4.3.2 Position Parameters

Position parameters’ values are measured in pixels. (Note that none of these parameters exist on TTY frames.)

left

The position, in pixels, of the left (or right) edge of the frame with respect to the left (or right) edge of the screen. The value may be:

an integer

A positive integer relates the left edge of the frame to the left edge of the screen. A negative integer relates the right frame edge to the right screen edge.

(+ pos)

This specifies the position of the left frame edge relative to the left screen edge. The integer pos may be positive or negative; a negative value specifies a position outside the screen or on a monitor other than the primary one (for multi-monitor displays).

(- pos)

This specifies the position of the right frame edge relative to the right screen edge. The integer pos may be positive or negative; a negative value specifies a position outside the screen or on a monitor other than the primary one (for multi-monitor displays).

Some window managers ignore program-specified positions. If you want to be sure the position you specify is not ignored, specify a non-nil value for the user-position parameter as well.

If the window manager refuses to align a frame at the left or top screen edge, combining position notation and user-position as in

(modify-frame-parameters
  nil '((user-position . t) (left . (+ -4))))

may help to override that.

top

The screen position of the top (or bottom) edge, in pixels, with respect to the top (or bottom) edge of the screen. It works just like left, except vertically instead of horizontally.

icon-left

The screen position of the left edge of the frame’s icon, in pixels, counting from the left edge of the screen. This takes effect when the frame is iconified, if the window manager supports this feature. If you specify a value for this parameter, then you must also specify a value for icon-top and vice versa.

icon-top

The screen position of the top edge of the frame’s icon, in pixels, counting from the top edge of the screen. This takes effect when the frame is iconified, if the window manager supports this feature.

user-position

When you create a frame and specify its screen position with the left and top parameters, use this parameter to say whether the specified position was user-specified (explicitly requested in some way by a human user) or merely program-specified (chosen by a program). A non-nil value says the position was user-specified.

Window managers generally heed user-specified positions, and some heed program-specified positions too. But many ignore program-specified positions, placing the window in a default fashion or letting the user place it with the mouse. Some window managers, including twm, let the user specify whether to obey program-specified positions or ignore them.

When you call make-frame, you should specify a non-nil value for this parameter if the values of the left and top parameters represent the user’s stated preference; otherwise, use nil.