Refactor HTML images handling of Gnus and mm-* (a part of bug#21650)

* doc/misc/emacs-mime.texi (Display Customization):
Remove mm-inline-text-html-with-images; add documentations for
mm-html-inhibit-images and mm-html-blocked-images.

* lisp/gnus/gnus-art.el (gnus-article-show-images):
No need to bind mm-inline-text-html-with-images.
(gnus-bind-safe-url-regexp): Rename to gnus-bind-mm-vars.
(gnus-bind-mm-vars): Rename from gnus-bind-safe-url-regexp;
bind mm-html-inhibit-images and mm-html-blocked-images.
(gnus-mime-view-all-parts, gnus-mime-view-part-internally)
(gnus-mm-display-part, gnus-mime-display-single)
(gnus-mime-display-alternative): Use gnus-bind-mm-vars.

* lisp/gnus/mm-decode.el (mm-inline-text-html-with-images): Remove.
(mm-html-inhibit-images, mm-html-blocked-images): New user options.
(mm-shr): Bind shr-inhibit-images and shr-blocked-images with
mm-html-inhibit-images and mm-html-blocked-images respectively
instead of gnus-inhibit-images and gnus-blocked-images.

* lisp/gnus/mm-view.el (mm-setup-w3m): Use mm-html-inhibit-images
instead of mm-inline-text-html-with-images.

1 files changed, 25 insertions, 10 deletions

diff --git a/doc/misc/emacs-mime.texi b/doc/misc/emacs-mime.texi
index b252b116a1c..64fed560f08 100644
--- a/doc/misc/emacs-mime.texi
+++ b/doc/misc/emacs-mime.texi
@@ -412,17 +412,32 @@ information about emacs-w3m}, @code{links}, @code{lynx},
 external viewer.  You can also specify a function, which will be
 called with a @acronym{MIME} handle as the argument.
 
-@item mm-inline-text-html-with-images
+@item mm-html-inhibit-images
+@vindex mm-html-inhibit-images
 @vindex mm-inline-text-html-with-images
-Some @acronym{HTML} mails might have the trick of spammers using
-@samp{<img>} tags.  It is likely to be intended to verify whether you
-have read the mail.  You can prevent your personal information from
-leaking by setting this option to @code{nil} (which is the default).
-For emacs-w3m, you may use the command @kbd{t} on the image anchor to
-show an image even if it is @code{nil}.@footnote{The command @kbd{T}
-will load all images.  If you have set the option
-@code{w3m-key-binding} to @code{info}, use @kbd{i} or @kbd{I}
-instead.}
+If this is non-@code{nil}, inhibit displaying of images inline in the
+article body.  It is effective to images that are in articles as
+@acronym{MIME} parts, and images in @acronym{HTML} articles rendered
+when @code{mm-text-html-renderer} (@pxref{Display Customization}) is
+@code{shr} or @code{w3m}.  In Gnus, this is overridden by the value
+of @code{gnus-inhibit-images} (@pxref{Misc Article, ,Misc Article, gnus,
+Gnus manual}).
+
+@item mm-html-blocked-images
+@vindex mm-html-blocked-images
+External images that have @acronym{URL}s that match this regexp won't
+be fetched and displayed.  For instance, do block all @acronym{URL}s
+that have the string ``ads'' in them, do the following:
+
+@lisp
+(setq mm-html-blocked-images "ads")
+@end lisp
+
+It is effective when @code{mm-text-html-renderer} (@pxref{Display
+Customization}) is @code{shr}.  In Gnus, this is overridden by the value
+of @code{gnus-blocked-images} or the return value of the function that
+@code{gnus-blocked-images} is set to (@pxref{HTML, ,HTML, gnus, Gnus
+manual}).
 
 @item mm-w3m-safe-url-regexp
 @vindex mm-w3m-safe-url-regexp