emacs-30 2b53e11a087: Use black-on-white by default for doc-view-svg-face.

[Tassilo Horn]

branch: emacs-30
commit 2b53e11a087be54f9ba7cd39334f7c14e89946ca
Author: Tassilo Horn <tsdh@gnu.org>
Commit: Tassilo Horn <tsdh@gnu.org>

    Use black-on-white by default for doc-view-svg-face.
    
    * lisp/doc-view.el (doc-view-svg-face): Define black on white as
    default value instead of using the current theme's values.
    * etc/NEWS: Adjust entry for doc-view-svg-face.
---
 etc/NEWS         | 10 ++++++----
 lisp/doc-view.el | 11 ++++++++---
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index 8ed16cfeeff..c72a87787f3 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1544,10 +1544,12 @@ default is non-nil if your system supports display of 
SVG images.
 ---
 *** New face 'doc-view-svg-face'.
 This replaces 'doc-view-svg-foreground' and 'doc-view-svg-background'.
-If you don't like the colors produced by the default definition of
-this new face when DocView displays documents, customize this face to
-restore the colors you were used to, or to get colors more to your
-liking.
+By default, this face has black foreground on white background and
+inherits from the default face.  When unsetting the foreground and
+background values, the display in DocView is styled according to the
+current theme.  However, this, or any non-standard values, can result in
+poor contrast for documents which aren't simply black text on white
+background.
 
 ---
 *** DocView buffers now display a new tool bar.
diff --git a/lisp/doc-view.el b/lisp/doc-view.el
index 15352630d25..1ed0c71febe 100644
--- a/lisp/doc-view.el
+++ b/lisp/doc-view.el
@@ -238,10 +238,15 @@ showing only titles and no page number."
   :type 'boolean
   :version "29.1")
 
-(defface doc-view-svg-face '((t :inherit default))
+(defface doc-view-svg-face '((t :inherit default
+                                :background "white"
+                                :foreground "black"))
   "Face used for SVG images.
-Only background and foreground colors are used.
-See `doc-view-mupdf-use-svg'."
+See `doc-view-mupdf-use-svg'.
+
+Only background and foreground colors are used as the SVG image's
+descriptors, see (info \"(elisp) SVG Images\").  Non-standard values may
+cause low-contrast issues with certain documents."
   :version "30.1")
 
 (make-obsolete 'doc-view-svg-background 'doc-view-svg-face "30.1")