[PATCH 1/1] emacs: Take more care when hiding regions with buttons.

[Dmitry Kurochkin]

On Wed, 25 Jan 2012 15:05:08 +0000, David Edmondson <dme at dme.org> wrote:
> If the region to be hidden with a button by
> `notmuch-wash-region-to-button' starts at the beginning of the buffer,
> the invisible region will include the inserted button. This is
> unfortunate, as it means that it is not possible to see the button to
> be pressed.
> 
> Make a little space at the start of the buffer before inserting the
> button to avoid this, not forgetting to remove the inserted space upon
> completion.
> ---
> 
> This is a hack, but I couldn't see another way around it. Can anyone
> find a better solution?
> 

I think it would be much easier to understand the problem and probably
suggest a solution if there is a test :)

Regards,
  Dmitry

>  emacs/notmuch-wash.el |   57 ++++++++++++++++++++++++++++++++----------------
>  1 files changed, 38 insertions(+), 19 deletions(-)
> 
> diff --git a/emacs/notmuch-wash.el b/emacs/notmuch-wash.el
> index 5c1e830..4afd3b3 100644
> --- a/emacs/notmuch-wash.el
> +++ b/emacs/notmuch-wash.el
> @@ -147,25 +147,44 @@ insert before the button, probably for indentation."
>    ;; symbols because of the way the button code works. Note that
>    ;; replacing intern-soft with make-symbol will cause this to fail,
>    ;; since the newly created symbol has no plist.
> -
> -  (let ((overlay (make-overlay beg end))
> -	(message-invis-spec (plist-get msg :message-invis-spec))
> -	(invis-spec (make-symbol (concat "notmuch-" type "-region")))
> -	(button-type (intern-soft (concat "notmuch-wash-button-"
> -					  type "-toggle-type"))))
> -    (add-to-invisibility-spec invis-spec)
> -    (overlay-put overlay 'invisible (list invis-spec message-invis-spec))
> -    (overlay-put overlay 'isearch-open-invisible #'notmuch-wash-region-isearch-show)
> -    (overlay-put overlay 'priority 10)
> -    (overlay-put overlay 'type type)
> -    (goto-char (1+ end))
> -    (save-excursion
> -      (goto-char (1- beg))
> -      (insert prefix)
> -      (insert-button (notmuch-wash-button-label overlay)
> -		     'invisibility-spec invis-spec
> -		     'overlay overlay
> -		     :type button-type))))
> +  (save-excursion
> +    ;; If the beginning of the region to be converted to a button is the
> +    ;; beginning of the buffer we must move forward a little to avoid
> +    ;; creating an overlay that will hide the button intended to be used
> +    ;; to reveal the hidden region.
> +    (let (scene-of-crime)
> +      (when (eq beg (point-min))
> +	(goto-char (point-min))
> +	(insert "\n")
> +	(setq scene-of-crime (point-min)
> +	      beg (point)))
> +
> +      ;; This uses some slightly tricky conversions between strings and
> +      ;; symbols because of the way the button code works. Note that
> +      ;; replacing intern-soft with make-symbol will cause this to fail,
> +      ;; since the newly created symbol has no plist.
> +
> +      (let ((overlay (make-overlay beg end))
> +	    (message-invis-spec (plist-get msg :message-invis-spec))
> +	    (invis-spec (make-symbol (concat "notmuch-" type "-region")))
> +	    (button-type (intern-soft (concat "notmuch-wash-button-"
> +					      type "-toggle-type"))))
> +	(add-to-invisibility-spec invis-spec)
> +	(overlay-put overlay 'invisible (list invis-spec message-invis-spec))
> +	(overlay-put overlay 'isearch-open-invisible #'notmuch-wash-region-isearch-show)
> +	(overlay-put overlay 'priority 10)
> +	(overlay-put overlay 'type type)
> +
> +	(goto-char (1- beg))
> +	(insert prefix)
> +	(insert-button (notmuch-wash-button-label overlay)
> +		       'invisibility-spec invis-spec
> +		       'overlay overlay
> +		       :type button-type))
> +
> +      (when scene-of-crime
> +      	(goto-char scene-of-crime)
> +      	(delete-char 1)))))
>  
>  (defun notmuch-wash-excerpt-citations (msg depth)
>    "Excerpt citations and up to one signature."
> -- 
> 1.7.8.3
> 
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