Add outline open/close images (bug#57813)

* etc/images/outline-open.svg:
* etc/images/outline-close.svg: New files.

* lisp/outline.el (outline-open, outline-close): Use images
outline-open.svg and outline-close.svg.

* lisp/emacs-lisp/icons.el (icons--create): Add :ascent 'center'.

4 files changed, 17 insertions, 5 deletions

diff --git a/etc/images/outline-close.svg b/etc/images/outline-close.svg
new file mode 100644
index 00000000000..ea9157a5fb5
--- /dev/null
+++ b/etc/images/outline-close.svg
@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 20 20">
+<title>outline-close</title>
+<g transform="rotate(-90, 10, 10)">
+<path d="m17.5 4.75-7.5 7.5-7.5-7.5L1 6.25l9 9 9-9z"/>
+</g>
+</svg>
diff --git a/etc/images/outline-open.svg b/etc/images/outline-open.svg
new file mode 100644
index 00000000000..75cf6aff9f9
--- /dev/null
+++ b/etc/images/outline-open.svg
@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 20 20">
+<title>outline-open</title>
+<path d="m17.5 4.75-7.5 7.5-7.5-7.5L1 6.25l9 9 9-9z"/>
+</svg>
diff --git a/lisp/emacs-lisp/icons.el b/lisp/emacs-lisp/icons.el
index 93749a3451e..ff4f20c2071 100644
--- a/lisp/emacs-lisp/icons.el
+++ b/lisp/emacs-lisp/icons.el
@@ -202,7 +202,7 @@ present if the icon is represented by an image."
                             :height (if (eq height 'line)
                                         (window-default-line-height)
                                       height)
-                            :scale 1)
+                            :scale 1 :ascent 'center)
             (create-image file))))))
 
 (cl-defmethod icons--create ((_type (eql 'emoji)) icon _keywords)
diff --git a/lisp/outline.el b/lisp/outline.el
index c9d1a4ac64b..aee6f696b5b 100644
--- a/lisp/outline.el
+++ b/lisp/outline.el
@@ -292,16 +292,18 @@ buffers (yet) -- that will be amended in a future version."
   :safe #'booleanp
   :version "29.1")
 
-(define-icon outline-open button
-  '((emoji "🔽")
+(define-icon outline-open nil
+  '((image "outline-open.svg" :height 15 :ascent center)
+    (emoji "🔽")
     (symbol " ▼ ")
     (text " open "))
   "Icon used for buttons for opening a section in outline buffers."
   :version "29.1"
   :help-echo "Open this section")
 
-(define-icon outline-close button
-  '((emoji "▶️")
+(define-icon outline-close nil
+  '((image "outline-close.svg" :height 15 :ascent center)
+    (emoji "▶️")
     (symbol " ▶ ")
     (text " close "))
   "Icon used for buttons for closing a section in outline buffers."