Re: How to create a small child-frame which only show two lines

["Feng Shu" <tumashu@163.com>]

martin rudalics <rudalics@gmx.at> writes:

The below is a simple version, and it works well for pyim and is easy
understand.

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(defun pyim-tooltip-compute-pixel-position (pos pixel-width pixel-height)
  "Return pixel position of POS in WINDOW, which indicates relative
coordinates of bottom left corner of the object, its returned value is
like (X . Y)

If PIXEL-WIDTH and PIXEL-HEIGHT are given, this function regard these
values as the size of a small window located around the POS, for example:
tooltip. These values are used to adjust the small window's location and
let it not disappear by sticking out of the display.

This function is shameless steal from pos-tip."
  (let* ((window (selected-window))
         (frame (window-frame window))
         (xmax (frame-pixel-width frame))
	     (ymax (frame-pixel-height frame))
         (posn (posn-at-point pos window))
         (line (cdr (posn-actual-col-row posn)))
         (line-height
		  (or (window-line-height line window)
			  (and (redisplay t)
				   (window-line-height line window))))
         (x-y (or (posn-x-y posn) '(0 . 0)))
         (x (+ (car (window-inside-pixel-edges window))
	           (car x-y)))
         (y0 (+ (cadr (window-pixel-edges window))
		        (or (nth 2 line-height) (cdr x-y))))
         (y (+ y0 (car line-height))))
    (cons (max 0 (min x (- xmax (or pixel-width 0))))
	      (max 0 (if (> (+ y (or pixel-height 0)) ymax)
		             (- y0 (or pixel-height 0))
                   y)))))

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