Re: [Emacs-diffs] /srv/bzr/emacs/trunk r103444: * lisp/facemenu.el (list-colors-display): Use with-help-window (Bug#8048).

[martin rudalics]

> Before this change
>
>> ------------------------------------------------------------
>> revno: 103444
>> committer: Chong Yidong <address@hidden>
>> branch nick: trunk
>> timestamp: Sun 2011-02-27 18:53:41 -0500
>> message:
>>  * lisp/facemenu.el (list-colors-display): Use with-help-window (Bug#8048).
>> modified:
>>  lisp/ChangeLog
>>  lisp/facemenu.el
>
> emacs -Q -f temp-buffer-resize-mode -f list-color-display
>
> shows *Colors* in a window `temp-buffer-max-height' lines tall. After
> the change, the buffer is `window-min-height' lines tall.

What happens is that in the new code

  (with-help-window buffer-name
    (with-current-buffer standard-output
      (erase-buffer)
      (setq truncate-lines t)))
  (let ((buf (get-buffer buffer-name))
        (inhibit-read-only t))
    ;; Display buffer before generating content, to allow
    ;; `list-colors-print' to get the right window-width.
    (with-selected-window (or (get-buffer-window buf t) (selected-window))
      (with-current-buffer buf
        (list-colors-print list callback)
        (set-buffer-modified-p nil)))
    (when callback
      (pop-to-buffer buf)
      (message "Click on a color to select it."))))

`with-help-window' eventually ends up calling `fit-window-to-buffer'
which, since the buffer is still empty at that time, makes the window
`window-min-height' lines tall.  Unfortunately, we can't fill the buffer
_before_ calling `with-help-window' because, as the comment above
indicates, `list-colors-print' wants to know the width of the window
_before_ filling the buffer.

We could fix this, slightly hacky, by rewriting the last part as

    ;; Display buffer before generating content, to allow
    ;; `list-colors-print' to get the right window-width.
    (with-selected-window (or (get-buffer-window buf t) (selected-window))
      (with-current-buffer buf
        (list-colors-print list callback)
        (when temp-buffer-resize-mode
          ;; Take real buffer size into account when
          ;; `temp-buffer-resize-mode' is on.
          (resize-temp-buffer-window))
        (set-buffer-modified-p nil)))

Note that binding `temp-buffer-resize-mode' around the call to
`with-help-window' won't help - we'd have to remove
`resize-temp-buffer-window' from `temp-buffer-show-hook' which doesn't
strike me as elegant either.

martin