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30.4.3.6 Frame Interaction Parameters

These parameters supply forms of interactions between different frames.

parent-frame

If non-nil, this means that this frame is a child frame (see Child Frames), and this parameter specifies its parent frame. If nil, this means that this frame is a normal, top-level frame.

delete-before

If non-nil, this parameter specifies another frame whose deletion will automatically trigger the deletion of this frame. See Deleting Frames.

mouse-wheel-frame

If non-nil, this parameter specifies the frame whose windows will be scrolled whenever the mouse wheel is scrolled with the mouse pointer hovering over this frame, see Mouse Commands in The GNU Emacs Manual.

no-other-frame

If this is non-nil, then this frame is not eligible as candidate for the functions next-frame, previous-frame (see Finding All Frames) and other-frame, see Frame Commands in The GNU Emacs Manual.

auto-hide-function

When this parameter specifies a function, that function will be called instead of the function specified by the variable frame-auto-hide-function when quitting the frame’s only window (see Quitting Windows) and there are other frames left.

minibuffer-exit

When this parameter is non-nil, Emacs will by default make this frame invisible whenever the minibuffer (see Minibuffers) is exited. Alternatively, it can specify the functions iconify-frame and delete-frame. This parameter is useful to make a child frame disappear automatically (similar to how Emacs deals with a window) when exiting the minibuffer.

keep-ratio

This parameter is currently meaningful for child frames (see Child Frames) only. If it is non-nil, then Emacs will try to keep the frame’s size (width and height) ratios (see Size Parameters) as well as its left and right position ratios (see Position Parameters) unaltered whenever its parent frame is resized.

If the value of this parameter is nil, the frame’s position and size remain unaltered when the parent frame is resized, so the position and size ratios may change. If the value of this parameter is t, Emacs will try to preserve the frame’s size and position ratios, hence the frame’s size and position relative to its parent frame may change.

More individual control is possible by using a cons cell: In that case the frame’s width ratio is preserved if the CAR of the cell is either t or width-only. The height ratio is preserved if the CAR of the cell is either t or height-only. The left position ratio is preserved if the CDR of the cell is either t or left-only. The top position ratio is preserved if the CDR of the cell is either t or top-only.