bug#24669: 25.1; Cannot display images

bug#24669: 25.1; Cannot display images

[Drew Adams]

emacs -Q

Try to visit an image file (e.g. foo.png).

I get this:

  Type C-c C-c to view the image as an image.
  Cannot display image: (Invalid image specification)

I do not have any such problem with Emacs 25 development builds such as
this one:

In GNU Emacs 25.1.50.1 (i686-pc-mingw32)
 of 2015-12-10
Repository revision: 6148555ee5a3d0139ae517803718b3e0357933c7
Windowing system distributor 'Microsoft Corp.', version 6.1.7601
Configured using:
 'configure --prefix=/c/Devel/emacs/snapshot/trunk --enable-checking=yes
 --enable-check-lisp-object-type --without-compress-install 'CFLAGS=-Og
 -ggdb3' LDFLAGS=-Lc:/Devel/emacs/lib 'CPPFLAGS=-DGC_MCHECK=1
 -Ic:/Devel/emacs/include''





In GNU Emacs 25.1.1 (x86_64-w64-mingw32)
 of 2016-09-17 built on LAPHROAIG
Windowing system distributor 'Microsoft Corp.', version 6.1.7601
Configured using:
 'configure --without-dbus --without-compress-install CFLAGS=-static'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252

Major mode: Fundamental

Minor modes in effect:
  image-minor-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Type C-c C-c to view the image as an image.
Cannot display image: (Invalid image specification)

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message format-spec rfc822 mml mml-sec
password-cache epg epg-config gnus-util mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util help-fns help-mode cl-loaddefs pcase cl-lib
mail-prsvr mail-utils image-mode easymenu dired time-date mule-util
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel dos-w32 ls-lisp disp-table w32-win w32-vars term/common-win
tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment
elisp-mode lisp-mode prog-mode register page menu-bar rfn-eshadow timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
frame cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan
thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian
slovak czech european ethiopic indian cyrillic chinese charscript
case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote w32notify w32 multi-tty
make-network-process emacs)

Memory information:
((conses 16 218720 20129)
 (symbols 56 19901 0)
 (miscs 48 64 128)
 (strings 32 16544 6241)
 (string-bytes 1 446656)
 (vectors 16 11965)
 (vector-slots 8 427494 5079)
 (floats 8 176 252)
 (intervals 56 48912 5257)
 (buffers 976 23))

bug#24669: 25.1; Cannot display images

[Eli Zaretskii]

> Date: Tue, 11 Oct 2016 14:56:04 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> emacs -Q
> 
> Try to visit an image file (e.g. foo.png).
> 
> I get this:
> 
>   Type C-c C-c to view the image as an image.
>   Cannot display image: (Invalid image specification)
> 
> I do not have any such problem with Emacs 25 development builds such as
> this one:
> 
> In GNU Emacs 25.1.50.1 (i686-pc-mingw32)
>  of 2015-12-10

What do you get with that version?  I get a different error message,
which is more confusing, something about missing map.  AFAIK, Emacs
always behaved this way, since the day "C-x C-f" started supporting
visiting image files automatically.

bug#24669: 25.1; Cannot display images

[Drew Adams]

> > I do not have any such problem with Emacs 25 development builds such as
> > this one:
> >
> > In GNU Emacs 25.1.50.1 (i686-pc-mingw32)
> >  of 2015-12-10
> 
> What do you get with that version?

Uh, I get the image displayed. That's what I meant by "I do not have
any such problem" with that build (or previous).

The same is true of all other Emacs releases and builds I have (starting with releases that support images).

> I get a different error message,
> which is more confusing, something about missing map.  AFAIK, Emacs
> always behaved this way, since the day "C-x C-f" started supporting
> visiting image files automatically.

I don't.  I don't get any error message.  "behaved this way" = ?

Are you saying that Emacs has always raised an error for C-x C-f
when visiting an image file?  A "different error message, which
is more confusing"?  I don't get any error message - I see the
image.  Always have.

bug#24669: 25.1; Cannot display images

[Eli Zaretskii]

> Date: Wed, 12 Oct 2016 06:44:03 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 24669@debbugs.gnu.org
> 
> > > I do not have any such problem with Emacs 25 development builds such as
> > > this one:
> > >
> > > In GNU Emacs 25.1.50.1 (i686-pc-mingw32)
> > >  of 2015-12-10
> > 
> > What do you get with that version?
> 
> Uh, I get the image displayed. That's what I meant by "I do not have
> any such problem" with that build (or previous).

Sorry, I misunderstood your report.  I thought foo.png was a
non-existing file.

If you are saying that your Emacs cannot display images, then my
crystal ball says you didn't install the 64-bit image DLLs.  The ones
you had before were 32-bit DLLs (because your Emacs was a 32-bit build
back then), which the new 64-bit binary cannot use.

You can find the 64-bit DLLs here:

  http://alpha.gnu.org/gnu/emacs/pretest/windows/emacs-25-x86_64-deps.zip

bug#24669: 25.1; Cannot display images

[Drew Adams]

> If you are saying that your Emacs cannot display images, then my
> crystal ball says you didn't install the 64-bit image DLLs.  The ones
> you had before were 32-bit DLLs (because your Emacs was a 32-bit build
> back then), which the new 64-bit binary cannot use.
> 
> You can find the 64-bit DLLs here:
>   http://alpha.gnu.org/gnu/emacs/pretest/windows/emacs-25-x86_64-deps.zip

But I have no problem displaying images with this, or similar, 64-bit Emacs builds:

In GNU Emacs 25.0.50.1 (x86_64-w64-mingw32)
 of 2014-11-14 on KAEL
Repository revision: a5cbb7d9cc072db90201dd6e7e597c424a7d015e
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/z/emacs --host=x86_64-w64-mingw32
 --target=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --with-wide-int
 --with-jpeg --with-xpm --with-png --with-tiff --with-rsvg --with-xml2
 --with-gnutls --with-xft --with-sound=yes --with-file-notification=yes
 --without-dbus --without-imagemagick 'CFLAGS=-Ofast
 -fomit-frame-pointer -funroll-loops -g0 -pipe' 'CPPFLAGS=-DNDEBUG
 -DDBUS_STATIC_BUILD' 'LDFLAGS=-static-libgcc -static-libstdc++ -static
 -s -Wl,-s''

Why is it that other 64-bit Windows builds have no problem showing
images, but 25.1 cannot do so?  Presumably I have the requisite
binaries installed (though I don't recall where, and would have to
look for them).

Even if that were not the case, I would not want to install ALL of
that stuff (which I nevertheless downloaded), just to be able to
display images.  I already have other versions (e.g. Cygwin) of grep
etc.

Which, of that mountain of stuff, are the things supposedly needed
to (just) display images?  (If nothing else, that will help me find
the binaries that I already have installed, and which work with other
Emacs 64-bit builds - presumably some of the names are the same as
or similar to files in the zip you pointed to.)

Or is there some other, easy way to tell which binaries are being
used for images in the 64-bit builds I have where images are
displayed OK?  If (really) necessary, I'll install (only) the
necessary binaries from the new zip in the same location (or
similar, if some of the files names are exactly the same).

bug#24669: 25.1; Cannot display images

[Eli Zaretskii]

> Date: Wed, 12 Oct 2016 08:22:30 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 24669@debbugs.gnu.org
> 
> > If you are saying that your Emacs cannot display images, then my
> > crystal ball says you didn't install the 64-bit image DLLs.  The ones
> > you had before were 32-bit DLLs (because your Emacs was a 32-bit build
> > back then), which the new 64-bit binary cannot use.
> > 
> > You can find the 64-bit DLLs here:
> >   http://alpha.gnu.org/gnu/emacs/pretest/windows/emacs-25-x86_64-deps.zip
> 
> But I have no problem displaying images with this, or similar, 64-bit Emacs builds:
> 
> In GNU Emacs 25.0.50.1 (x86_64-w64-mingw32)
>  of 2014-11-14 on KAEL
> Repository revision: a5cbb7d9cc072db90201dd6e7e597c424a7d015e
> Windowing system distributor `Microsoft Corp.', version 6.1.7601
> Configured using:
>  `configure --prefix=/z/emacs --host=x86_64-w64-mingw32
>  --target=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --with-wide-int
>  --with-jpeg --with-xpm --with-png --with-tiff --with-rsvg --with-xml2
>  --with-gnutls --with-xft --with-sound=yes --with-file-notification=yes
>  --without-dbus --without-imagemagick 'CFLAGS=-Ofast
>  -fomit-frame-pointer -funroll-loops -g0 -pipe' 'CPPFLAGS=-DNDEBUG
>  -DDBUS_STATIC_BUILD' 'LDFLAGS=-static-libgcc -static-libstdc++ -static
>  -s -Wl,-s''                                                    ^^^^^^^
> 
> Why is it that other 64-bit Windows builds have no problem showing
> images, but 25.1 cannot do so?

I can only guess: that other 64-bit build has all the necessary
libraries statically linked into the binary: see the marked "-static"
link-time switch above.

> Presumably I have the requisite binaries installed (though I don't
> recall where, and would have to look for them).

No, I think you don't have them, at least not where Windows looks for
DLLs for Emacs.

> Even if that were not the case, I would not want to install ALL of
> that stuff (which I nevertheless downloaded), just to be able to
> display images.  I already have other versions (e.g. Cygwin) of grep
> etc.

There's no grep in that archive, only shell scripts that call grep.
They are there because they are part of the bzip2 library, which is
required by some of the image DLLs.

> Which, of that mountain of stuff, are the things supposedly needed
> to (just) display images?

Almost all of them.  Apart of image DLLs, that zip file includes
GnuTLS (required for HTTPS networking) and libxml2 (required for
browsing HTML and XML files).  These two non-image libraries have
dependency libraries, of course, but other than that, all the rest is
for images of several kinds.

bug#24669: 25.1; Cannot display images

[Drew Adams]

> > Why is it that other 64-bit Windows builds have no problem
> > showing images, but 25.1 cannot do so?
> 
> I can only guess: that other 64-bit build has all the necessary
> libraries statically linked into the binary: see the marked
> "-static" link-time switch above.

Got it.

> > Presumably I have the requisite binaries installed (though I don't
> > recall where, and would have to look for them).
> 
> No, I think you don't have them, at least not where Windows looks for
> DLLs for Emacs.

OK.

> > Which, of that mountain of stuff, are the things supposedly needed
> > to (just) display images?
> 
> Almost all of them.  Apart of image DLLs, that zip file includes
> GnuTLS (required for HTTPS networking) and libxml2 (required for
> browsing HTML and XML files).  These two non-image libraries have
> dependency libraries, of course, but other than that, all the rest is
> for images of several kinds.

Thanks very much for all of this info.  I will close the bug.

(I wonder if some such info should be, or maybe already is, in
the doc somewhere.  You will likely tell me that it is in the
Windows README or some such, but I'm thinking of someone who
just picks up an Emacs binary.  Should this be in the Emacs
manual (or is it already)?)

bug#24669: 25.1; Cannot display images

[Drew Adams]

> (I wonder if some such info should be, or maybe already is, in
> the doc somewhere.  You will likely tell me that it is in the
> Windows README or some such, but I'm thinking of someone who
> just picks up an Emacs binary.  Should this be in the Emacs
> manual (or is it already)?)

Just which of the directories in that zip archive need to be included in my PATH variable?  All of them?  (Including only bin/ is apparently not sufficient.)

bug#24669: 25.1; Cannot display images

[Eli Zaretskii]

> Date: Wed, 12 Oct 2016 09:33:55 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 24669@debbugs.gnu.org
> 
> (I wonder if some such info should be, or maybe already is, in
> the doc somewhere.  You will likely tell me that it is in the
> Windows README or some such, but I'm thinking of someone who
> just picks up an Emacs binary.  Should this be in the Emacs
> manual (or is it already)?)

We keep this info in README.W32, which should be in the zip file.

bug#24669: 25.1; Cannot display images

[Drew Adams]

> We keep this info in README.W32, which should be in the zip file.

No, not that I can find.  I find only these files whose names match
"README":

README - in dirs
 etc/fonts/conf.d
 share/doc/gettext/examples/hello-csharp-forms
 share/doc/gettext/examples/hello-php
 share/doc/gettext/examples
 share/doc/libjpeg-turbo
 share/doc/tiff-4.0.6
 share/doc/xz
 share/licenses/gcc-libs
 share/licenses/libiconv
 share/licenses/libjpeg-turbo
 share/licenses/pango

README.vms in dir share/doc/tiff-4.0.6
README-turbo.txt in dirs
 share/doc/libjpeg-turbo
 share/licenses/libjpeg-turbo

00_README.txt in dir share/doc/xz/examples

What I'm looking for now is just what dirs I need to add to
my PATH env var.

bug#24669: 25.1; Cannot display images

[Eli Zaretskii]

> Date: Wed, 12 Oct 2016 09:55:08 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 24669@debbugs.gnu.org
> 
> > (I wonder if some such info should be, or maybe already is, in
> > the doc somewhere.  You will likely tell me that it is in the
> > Windows README or some such, but I'm thinking of someone who
> > just picks up an Emacs binary.  Should this be in the Emacs
> > manual (or is it already)?)
> 
> Just which of the directories in that zip archive need to be included in my PATH variable?  All of them?  (Including only bin/ is apparently not sufficient.)

Only bin/, the one where all the DLL files are.

How is that not sufficient?

bug#24669: 25.1; Cannot display images

[Drew Adams]

> Only bin/, the one where all the DLL files are.
> How is that not sufficient?

My bad.  Copy+paste error.  It works fine, now.  Thx.

(You might want to look into the seemingly missing README.W32,
and make sure that some doc says to put such things in your
PATH.)

bug#24669: 25.1; Cannot display images

[Eli Zaretskii]

> Date: Wed, 12 Oct 2016 10:14:46 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 24669@debbugs.gnu.org
> 
> > We keep this info in README.W32, which should be in the zip file.
> 
> No, not that I can find.

That's a packaging bug, then.  You can find the file here:

  http://git.savannah.gnu.org/cgit/emacs.git/tree/nt/README.W32?h=emacs-25

> What I'm looking for now is just what dirs I need to add to
> my PATH env var.

The above file says:

  Emacs will find these libraries if the directory they are installed
  in is on the PATH or in the same directory where you have emacs.exe.

But that's, of course, a general Windows system configuration note,
not something specific to Emacs and/or those DLLs.

It's possible that the "deps" zip file should have a README of its
own, I don't know.

bug#24669: 25.1; Cannot display images

[Drew Adams]

> > > We keep this info in README.W32, which should be in the zip file.
> >
> > No, not that I can find.
> 
> That's a packaging bug, then.  You can find the file here:
> 
>   http://git.savannah.gnu.org/cgit/emacs.git/tree/nt/README.W32?h=emacs-25
> 
> > What I'm looking for now is just what dirs I need to add to
> > my PATH env var.
> 
> The above file says:
> 
>   Emacs will find these libraries if the directory they are installed
>   in is on the PATH or in the same directory where you have emacs.exe.

But in the case of the zip I downloaded, there are lots of files, in
several directories.  It wasn't clear to me, at least, which of those
are "these libraries", so it wasn't clear which directories to add to
PATH.

> But that's, of course, a general Windows system configuration note,
> not something specific to Emacs and/or those DLLs.
> 
> It's possible that the "deps" zip file should have a README of its
> own, I don't know.

Ideal would, I think, be something in the Emacs manual.  Displaying
images should not be something that users need to hunt for how to do.

bug#24669: 25.1; Cannot display images

[Eli Zaretskii]

> Date: Wed, 12 Oct 2016 10:57:22 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 24669@debbugs.gnu.org
> 
> > It's possible that the "deps" zip file should have a README of its
> > own, I don't know.
> 
> Ideal would, I think, be something in the Emacs manual.  Displaying
> images should not be something that users need to hunt for how to do.

That could only happen if the current volunteers that upload Windows
binaries will keep doing that for a period long enough to be recorded
in the manual.  Since each volunteer gets to select the methods of
packaging, we cannot afford documenting that unless it's more or less
"accepted practices".

bug#24669: 25.1; Cannot display images

[Drew Adams]

> > Ideal would, I think, be something in the Emacs manual.  Displaying
> > images should not be something that users need to hunt for how to do.
> 
> That could only happen if the current volunteers that upload Windows
> binaries will keep doing that for a period long enough to be recorded
> in the manual.  Since each volunteer gets to select the methods of
> packaging, we cannot afford documenting that unless it's more or less
> "accepted practices".

OK. If there cannot be a generic level of such info, then so be it.