Fix Proced display header alignment under 'text-scale-adjust'

* lisp/proced.el (proced-mode): Force the header-line to scale
according to 'text-scale-adjust'.
(proced-header-line): Use width of the header-line's face's
characters as align-to units, not the width of the frame's
default face's font.  (Bug#64752)

* src/xdisp.c (calc_pixel_width_or_height): Use font's
average_width or space_width, not max_width, as the correct
measure of the font's width.  This is consistent with the rest of
the display engine.

2 files changed, 7 insertions, 3 deletions

diff --git a/lisp/proced.el b/lisp/proced.el
index 03a7f1bebdf..b3d581a49d1 100644
--- a/lisp/proced.el
+++ b/lisp/proced.el
@@ -776,12 +776,12 @@ of the process.  A value of nil indicates that there are no active refinements."
         (while (string-match "[ \t\n]+" hl pos)
           (setq pos (match-end 0))
           (put-text-property (match-beginning 0) pos 'display
-                             `(space :align-to ,(+ pos base))
+                             `(space :align-to (,(+ pos base) . width))
                              hl)))
       (setq hl (replace-regexp-in-string ;; preserve text properties
                 "\\(%\\)" "\\1\\1"
                 hl)))
-    (list (propertize " " 'display `(space :align-to ,base))
+    (list (propertize " " 'display `(space :align-to (,base . width)))
           hl)))
 
 (defun proced-pid-at-point ()
@@ -894,6 +894,8 @@ normal hook `proced-post-display-hook'.
   (setq-local font-lock-defaults
               '(proced-font-lock-keywords t nil nil beginning-of-line))
   (setq-local switch-to-buffer-preserve-window-point nil)
+  ;; So that the heading scales together with the body of the table.
+  (setq-local text-scale-remap-header-line t)
   (if (and (not proced-auto-update-timer) proced-auto-update-interval)
       (setq proced-auto-update-timer
             (run-at-time t proced-auto-update-interval
diff --git a/src/xdisp.c b/src/xdisp.c
index da6e0afa8e1..2eba42e3d90 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -29093,7 +29093,9 @@ calc_pixel_width_or_height (double *res, struct it *it, Lisp_Object prop,
       /* 'width': the width of FONT.  */
       if (EQ (prop, Qwidth))
         return OK_PIXELS (font
-                          ? FONT_WIDTH (font)
+                          ? (font->average_width
+                             ? font->average_width
+                             : font->space_width)
                           : FRAME_COLUMN_WIDTH (it->f));
 #else
       if (EQ (prop, Qheight) || EQ (prop, Qwidth))