Re: [BUG] ov property line height failed on lone length line when exceeded window width

[stardiviner <numbchild@gmail.com>]

Eli Zaretskii <eliz@gnu.org> writes:

> [Please use "Reply All" to keep the list CC'ed.]
>
>> From: "numbchild@gmail.com" <numbchild@gmail.com>
>> Date: Wed, 3 Jun 2020 19:48:57 +0800
>> 
>> > Can you please describe how you set the overlay, or better yet, show the code which does so? 
>> 
>> The main functionality code set overlay on org-agenda is here:
>> 
>> (defun org-agenda-log-mode-colorize-block ()
>>   "Set different line spacing based on clock time duration."
>>   (save-excursion
>>     (let* ((colors (cl-case (alist-get 'background-mode (frame-parameters))
>>                 ('light
>>                  (list "#F6B1C3" "#FFFF9D" "#BEEB9F" "#ADD5F7"))
>>                 ('dark
>>                  (list "#aa557f" "DarkGreen" "DarkSlateGray" "DarkSlateBlue"))))
>>            pos
>>            duration)
>>       (nconc colors colors)
>>       (goto-char (point-min))
>>       (while (setq pos (next-single-property-change (point) 'duration))
>>         (goto-char pos)
>>         (when (and (not (equal pos (point-at-eol)))
>>                    (setq duration (org-get-at-bol 'duration)))
>>           ;; larger duration bar height
>>           ;; FIXME (< duration 15)
>>           (let ((line-height (if (< duration 15) 1.0 (+ 0.5 (/ duration 30))))
>>                 (ov (make-overlay (point-at-bol) (1+ (point-at-eol)))))
>>             (overlay-put ov 'face `(:background ,(car colors) :foreground "black"))
>>             (setq colors (cdr colors))
>>             (overlay-put ov 'line-height line-height)
>>             (overlay-put ov 'line-spacing (1- line-height))))))))
>> 
>> (add-hook 'org-agenda-finalize-hook #'org-agenda-log-mode-colorize-block)
>> 
>> And for a minimal example of setting overlay code is here:
>> 
>> (let ((line-height 20)
>>       (ov (make-overlay (point-at-bol) (1+ (point-at-eol)))))
>>   (overlay-put ov 'face '(:background "yellow"))
>>   (overlay-put ov 'line-height line-height)
>>   (overlay-put ov 'line-spacing (1- line-height)))
>> 
>> > Did you per chance put the overlay on the part of the line that is not shown when you split the window?
>> 
>> About this problem, I suggest you check out my video link, it shows how the overlay line-height property failed
>> when I split window with `split-window-right`. The line height property is gone. (I mean the visual effect is
>> gone.)
>
> In that case, this is the expected behavior: if the newline with the
> line-height property is not visible, the setting has no effect.  It is
> conceptually the same as having a tall character or image displayed on
> a line: if you then truncate the line so that the tall element is not
> visible, the line's height will be decreased to reflect what is
> actually on display.

I have a little kind of understand. Hmm, is there any workaround of this
situation? I want it to be displayed anyway. Change my code, or toggle some
options or something else?

>
> This is not a bug.  You are trying to use this property in a way that
> it wasn't designed to support.


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