Variable: image-dired-cmd-create-standard-thumbnail-options
image-dired-cmd-create-standard-thumbnail-options is a customizable
variable defined in image-dired-external.el.gz.
Value
("-size" "%wx%h" "%f[0]" "-set" "Thumb::MTime" "%m" "-set"
"Thumb::URI" "file://%u" "-set" "Description"
"Thumbnail of file://%u" "-set" "Software"
"GNU Emacs 30.2 (build 1, x86_64-pc-linux-gnu)" "-thumbnail" "%wx%h>"
"png:%t")
Documentation
Options for creating thumbnails according to the Thumbnail Managing Standard.
Used with image-dired-cmd-create-thumbnail-program, if that is available.
The value can use the same %-format specifiers as in
image-dired-cmd-create-thumbnail-options, with "%m" for file
modification time and "%u" for the URI of the file in "%f".
On MS-Windows, if the convert command is not available, and
w32image-create-thumbnail is used instead, the textual chunks
specified by the "-set" options will not be injected, and instead
they are added by pngcrush if that is available.
This variable was added, or its default value changed, in Emacs 29.1.
Probably introduced at or before Emacs version 26.1.
Source Code
;; Defined in /usr/src/emacs/lisp/image/image-dired-external.el.gz
;; Note: the "-set" arguments below are according to specification in
;; https://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html#CREATION
(defcustom image-dired-cmd-create-standard-thumbnail-options
(let ((opts (list
"-size" "%wx%h" "%f[0]"
"-set" "Thumb::MTime" "%m"
"-set" "Thumb::URI" "file://%u"
"-set" "Description" "Thumbnail of file://%u"
"-set" "Software" (string-replace "\n" " " (emacs-version))
"-thumbnail" "%wx%h>" "png:%t")))
(if (executable-find "gm") (cons "convert" opts) opts))
"Options for creating thumbnails according to the Thumbnail Managing Standard.
Used with `image-dired-cmd-create-thumbnail-program', if that is available.
The value can use the same %-format specifiers as in
`image-dired-cmd-create-thumbnail-options', with \"%m\" for file
modification time and \"%u\" for the URI of the file in \"%f\".
On MS-Windows, if the `convert' command is not available, and
`w32image-create-thumbnail' is used instead, the textual chunks
specified by the \"-set\" options will not be injected, and instead
they are added by `pngcrush' if that is available."
:type '(repeat (string :tag "Argument"))
:version "29.1")