Function: frame-geom-value-cons
frame-geom-value-cons is a byte-compiled function defined in
frame.el.gz.
Signature
(frame-geom-value-cons TYPE VALUE &optional FRAME)
Documentation
Return equivalent geometry value for FRAME as a cons with car +.
A geometry value equivalent to VALUE for FRAME is returned,
where the value is a cons with car +, not numeric.
TYPE is the car of the original geometry spec (TYPE . VALUE).
It is top or left, depending on which edge VALUE is related to.
VALUE is the cdr of a frame geometry spec: (left/top . VALUE).
If VALUE is a number, then it is converted to a cons value, perhaps
relative to the opposite frame edge from that in the original spec.
FRAME defaults to the selected frame.
Examples (measures in pixels) -
Assuming display height/width=1024, frame height/width=600:
300 inside display edge: 300 => (+ 300)
(+ 300) => (+ 300)
300 inside opposite display edge: (- 300) => (+ 124)
-300 => (+ 124)
300 beyond display edge
(= 724 inside opposite display edge): (+ -300) => (+ -300)
300 beyond display edge
(= 724 inside opposite display edge): (- -300) => (+ 724)
In the 3rd, 4th, and 6th examples, the returned value is relative to the opposite frame edge from the edge indicated in the input spec.
Source Code
;; Defined in /usr/src/emacs/lisp/frame.el.gz
;;;; Frame geometry values
(defun frame-geom-value-cons (type value &optional frame)
"Return equivalent geometry value for FRAME as a cons with car `+'.
A geometry value equivalent to VALUE for FRAME is returned,
where the value is a cons with car `+', not numeric.
TYPE is the car of the original geometry spec (TYPE . VALUE).
It is `top' or `left', depending on which edge VALUE is related to.
VALUE is the cdr of a frame geometry spec: (left/top . VALUE).
If VALUE is a number, then it is converted to a cons value, perhaps
relative to the opposite frame edge from that in the original spec.
FRAME defaults to the selected frame.
Examples (measures in pixels) -
Assuming display height/width=1024, frame height/width=600:
300 inside display edge: 300 => (+ 300)
(+ 300) => (+ 300)
300 inside opposite display edge: (- 300) => (+ 124)
-300 => (+ 124)
300 beyond display edge
(= 724 inside opposite display edge): (+ -300) => (+ -300)
300 beyond display edge
(= 724 inside opposite display edge): (- -300) => (+ 724)
In the 3rd, 4th, and 6th examples, the returned value is relative to
the opposite frame edge from the edge indicated in the input spec."
(cond ((and (consp value) (eq '+ (car value))) ; e.g. (+ 300), (+ -300)
value)
((natnump value) (list '+ value)) ; e.g. 300 => (+ 300)
(t ; e.g. -300, (- 300), (- -300)
(list '+ (- (if (eq 'left type) ; => (+ 124), (+ 124), (+ 724)
(x-display-pixel-width)
(x-display-pixel-height))
(if (integerp value) (- value) (cadr value))
(if (eq 'left type)
(frame-pixel-width frame)
(frame-pixel-height frame)))))))