bug#31684: 12.1.1; Preview-DviPNG fails with filename having spaces (DviPS is used as fallback)

[Ikumi Keita]

Hi Jean and all,

>>>>> jfbu <address@hidden> writes:
> Experience 2: name it as abc def ghi.tex (so it includes spaces in filename)
> Switch to DVI mode
> Ask to generate previews for all document.
> Answer YES to "Cache preamble?"
> It **appears to work** but in fact it doesn't: 

> ....
> Running `Preview-DviPNG' with ``dvipng -picky -noghostscript abc\ def\ 
> ghi.dvi -o "abc\ def\ ghi.prv/tmp14749czs/prev%03d.png"  -D186 ''
> This is dvipng (dvipng (TeX Live)) 1.15 Copyright 2002-2015 Jan-Ake Larsson
> [1 (preview-latex version 12.1) (preview-latex tightpage option detected, 
> will use its bounding box)
> dvipng: Fatal error, cannot open output file abc\ def\ 
> ghi.prv/tmp14749czs/prev001.png

Confirmed.  It seems the reason is that `preview-dvipng-command'
contains spurious quotes.  Various `preview-*-command' are defined as:
(defcustom preview-dvipng-command
  "dvipng -picky -noghostscript %d -o \"%m/prev%%03d.png\""
  ...
(defcustom preview-dvips-command
  "dvips -Pwww -i -E %d -o %m/preview.000"
  ...
(defcustom preview-fast-dvips-command
  "dvips -Pwww %d -o %m/preview.ps"
  ...
(defcustom preview-pdf2dsc-command
  "pdf2dsc %s.pdf %m/preview.dsc"
  ...
.  They don't have quotes around %m except `preview-dvipng-command'.
Removing the quotes makes dvipng works with file name with space on my
side.

In addition, I noticed during test runs that single quotes in
`preview-dvipng-color-string' choke dvipng on w32 platform because
single quotes are not consumed by w32 shell (cmd.exe).

Could you please test the following patch?  (It is for preview.el.in in
the source files, not for preview.el.)

Regards,
Ikumi Keita

diff --git a/preview.el.in b/preview.el.in
--- a/preview.el.in
+++ b/preview.el.in
@@ -522,7 +522,7 @@
 be consulted recursively.")
 
 (defcustom preview-dvipng-command
-  "dvipng -picky -noghostscript %d -o \"%m/prev%%03d.png\""
+  "dvipng -picky -noghostscript %d -o %m/prev%%03d.png"
   "*Command used for converting to separate PNG images.
 
 You might specify options for converting to other image types,
@@ -796,13 +796,13 @@
        (border (aref colors 3)))
     (concat
      (and bg
-         (format "--bg 'rgb %s' "
+         (format "--bg \"rgb %s\" "
                  (mapconcat #'preview-gs-color-value bg " ")))
      (and fg
-         (format "--fg 'rgb %s' "
+         (format "--fg \"rgb %s\" "
                  (mapconcat #'preview-gs-color-value fg " ")))
      (and mask border
-         (format "--bd 'rgb %s' "
+         (format "--bd \"rgb %s\" "
                  (mapconcat #'preview-gs-color-value mask " ")))
      (and border
          (format "--bd %d" (max 1 (round (/ (* res border) 72.0))))))))