New faces 'tab-line-active' and 'tab-line-inactive' (bug#80742)HEADmaster

This is intended to parallel the 'mode-line-active/inactive'
and 'header-line-active/inactive' distinction.

* doc/emacs/display.texi (Standard Faces): Document the new faces.

* lisp/faces.el (tab-line-active, tab-line-inactive): Add new faces.

* lisp/tab-line.el (tab-line-faces): Add new faces
to MEMBERS arg of 'defgroup'.
(tab-line-auto-hscroll): Use one of the faces
depending on 'mode-line-window-selected-p'.

* src/dispextern.h (CURRENT_TAB_LINE_ACTIVE_FACE_ID_3)
(CURRENT_TAB_LINE_ACTIVE_FACE_ID): New macros
based on header-line equivalents.
(CURRENT_TAB_LINE_HEIGHT): Use CURRENT_TAB_LINE_ACTIVE_FACE_ID.
(face_id): Use TAB_LINE_ACTIVE_FACE_ID and
TAB_LINE_INACTIVE_FACE_ID instead of TAB_LINE_FACE_ID.

* src/xdisp.c (window_box_height, pos_visible_p, init_iterator)
(window_text_pixel_size, display_mode_lines, display_mode_line)
(format-mode-line): Replace all uses of TAB_LINE_FACE_ID with
either a new macro or the new face IDs.

* src/xfaces.c (lookup_basic_face, realize_basic_faces):
Map new face IDs to their lisp symbols.
(syms_of_xfaces): New lisp symbols.

2 files changed, 28 insertions, 6 deletions

diff --git a/lisp/faces.el b/lisp/faces.el
index 6fe94927290..97620822b88 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -3005,7 +3005,22 @@ Note: Other faces cannot inherit from the cursor face."
      :background "grey")
     (t
      :inverse-video t))
-  "Tab line face."
+  "Basic tab line face.
+See `tab-line-active' and `tab-line-inactive' for the faces
+used on tab lines."
+  :version "31.1"
+  :group 'basic-faces)
+
+(defface tab-line-active
+  '((t :inherit tab-line))
+  "Face for the selected tab line.
+This inherits from the `tab-line' face."
+  :version "31.1"
+  :group 'basic-faces)
+
+(defface tab-line-inactive
+  '((t :inherit tab-line))
+  "Basic tab line face for non-selected windows."
   :version "31.1"
   :group 'basic-faces)
 
diff --git a/lisp/tab-line.el b/lisp/tab-line.el
index 832b2b74437..524799e445d 100644
--- a/lisp/tab-line.el
+++ b/lisp/tab-line.el
@@ -54,7 +54,11 @@ is selected."
   :group 'tab-line
   :version "28.1")
 
-(defgroup tab-line-faces '((tab-line custom-face)) ; tab-line is defined in faces.el
+(defgroup tab-line-faces
+  ;; These faces are defined in faces.el
+  '((tab-line custom-face)
+    (tab-line-active custom-face)
+    (tab-line-inactive custom-face))
   "Faces used in the tab line."
   :group 'tab-line
   :group 'faces
@@ -860,13 +864,16 @@ the selected tab visible."
   (with-current-buffer tab-line-auto-hscroll-buffer
     (let ((truncate-partial-width-windows nil)
           (inhibit-modification-hooks t)
+          (face (if (mode-line-window-selected-p)
+                    'tab-line-active
+                  'tab-line-inactive))
           show-arrows)
       (setq truncate-lines nil
             word-wrap nil)
       (erase-buffer)
       (apply 'insert strings)
       (goto-char (point-min))
-      (add-face-text-property (point-min) (point-max) 'tab-line t)
+      (add-face-text-property (point-min) (point-max) face t)
       ;; Continuation means tab-line doesn't fit completely,
       ;; thus scroll arrows are needed for scrolling.
       (setq show-arrows (> (vertical-motion 1) 0))
@@ -888,7 +895,7 @@ the selected tab visible."
             (erase-buffer)
             (apply 'insert (reverse (seq-subseq strings 0 (1+ selected))))
             (goto-char (point-min))
-            (add-face-text-property (point-min) (point-max) 'tab-line)
+            (add-face-text-property (point-min) (point-max) face)
             (if (> (vertical-motion 1) 0)
                 (let* ((point (previous-single-property-change (point) 'tab))
                        (tab-prop (when point
@@ -909,13 +916,13 @@ the selected tab visible."
             (erase-buffer)
             (apply 'insert (seq-subseq strings (truncate hscroll) (1+ selected)))
             (goto-char (point-min))
-            (add-face-text-property (point-min) (point-max) 'tab-line)
+            (add-face-text-property (point-min) (point-max) face)
             (when (> (vertical-motion 1) 0)
               ;; Not visible already
               (erase-buffer)
               (apply 'insert (reverse (seq-subseq strings 0 (1+ selected))))
               (goto-char (point-min))
-              (add-face-text-property (point-min) (point-max) 'tab-line)
+              (add-face-text-property (point-min) (point-max) face)
               (when (> (vertical-motion 1) 0)
                 (let* ((point (previous-single-property-change (point) 'tab))
                        (tab-prop (when point