Subject: bug#34138: 27.0.50; Delayed display of PDF file images

From: martin rudalics <[email-masked]>
Date: Sun, 20 Jan 2019 15:19:56 +0100

> I can reproduce this: Opening a PDF in the latest Emacs version requires
 > an extra redisplay for the image to appear, e.g. by entering the
 > minibuffer.

Do you have any idea what might be causing it?  Excluding
'display-buffer-split-below-and-attach' it should be related to
'image-mode-new-window-functions'.

 >> 'display-buffer-split-below-and-attach' calls 'window--display-buffer'
 >> with a fifth argument and that has been changed in another commit.
 >
 > I really wish this function would be part of the public API. Or else,
 > what is the best way to implement a function like
 > display-buffer-mark-dedicated ?

It will be public soon.  Moreove, application will not have to bother
with ‘display-buffer-mark-dedicated’ any more.

 >>> In addition, in pdf-view-mode this appears in *Message*:
 >>> Error during redisplay: (eval (pdf-misc-size-indication)) signaled
 >>> (error "Invalid image specification: nil").
 >>
 >> This should come from the 'image-display-size' call in
 >> 'pdf-view-image-size'.  Could you get a backtrace for it?
 >
 > Right, the function pdf-misc-size-indication assumes the existence of a
 > displayed image in the selected window.

What happened here?  Did the image not get displayed or did the
selected window change or get another buffer?

martin