bug#13887: 24.3; doc-view will render blurry images when image-magick is available

[E Sabof]

The overlay with t value has precedence over other overlays. If the problem occurs, I can run the following function, and it will get fixed in existing windows. However if I create a new window, it will show only text. If I press + in that window, a new overlay will be created. Perhaps the t overlay was meant to be the default, and someone misunderstood it's effect.

(defun 13887-fix-helper1 ()

  (interactive)

  (let* ((ovs (overlays-at (point)))

         (ov-t (find-if (lambda (ov) (eq (overlay-get ov 'window) t))

                        ovs)))

    (when ov-t (delete-overlay ov-t))))

Here is one more helper function which might be useful.

(defun 13887-own-overlay-present-p ()

  (interactive)

  (let* ((ovs (overlays-at (point))))

    (find-if (lambda (ov) (eq (overlay-get ov 'window)

                              (selected-window)))

             ovs)))