feat: true screen magnifier — global default face + pinned modeline/minibuffer

config.el

@@ -698,96 +698,103 @@ Skips past the TODO keyword and optional priority indicator [#A]."
 ;;; ============================================================
 ;;; ACCESSIBILITY — GLOBAL TEXT SCALING (SPC z)
 ;;; ============================================================
-;; Uses per-buffer `text-scale-mode' applied to ALL buffers simultaneously.
-;; Unlike `default-text-scale', this scales ONLY buffer text.
-;; Modeline, minibuffer, which-key, corfu popups stay at base size
-;; and remain fully visible and usable even at very high zoom levels.
+;; True screen magnifier: scales the global `default' face (all buffers,
+;; help windows, doom menus, org-agenda, magit — everything).
 ;;
-;; Step: ×1.5 per step (multiplicative).  From 14pt base:
-;;   +1 → ×1.5  ≈ 21pt   +2 → ×2.25 ≈ 32pt
-;;   +3 → ×3.4  ≈ 47pt   +4 → ×5.1  ≈ 71pt
-;;   +5 → ×7.6  ≈ 106pt
+;; Modeline + minibuffer are PINNED to base size after every zoom so they
+;; stay fully visible and usable regardless of zoom level.
+;; which-key shows in the minibuffer area → also stays readable.
 ;;
-;; SPC z +  /  SPC z =   zoom in
-;; SPC z -               zoom out
-;; SPC z 0               reset to default (saves for restore)
-;; SPC z z               restore previous zoom
+;; Step: ×1.5 per step (multiplicative, not additive).  From 14pt base:
+;;   +1 ≈ 21pt    +2 ≈ 32pt    +3 ≈ 47pt
+;;   +4 ≈ 71pt    +5 ≈ 106pt   +6 ≈ 159pt
+;;
+;; SPC z +  /  =   zoom in
+;; SPC z -         zoom out
+;; SPC z 0         reset to default (saves level for restore)
+;; SPC z z         restore zoom before last reset
 
-(setq text-scale-mode-step 1.5)
+;; Base height: captured once at startup (reflects doom-font :size).
+;; Fallback to 140 = 14pt if face-attribute returns non-integer.
+(defvar my/zoom-base-height 140
+  "Default face height before any zoom. Captured at Doom init.")
 
 (defvar my/zoom-steps 0
-  "Current global zoom step count. 0 = default, positive = bigger.")
+  "Current zoom step count. 0 = default.")
 
 (defvar my/zoom-saved-steps nil
-  "Step count saved before last `my/zoom-reset', for restore.")
+  "Step count saved before last `my/zoom-reset', for `my/zoom-restore'.")
 
-(defun my/zoom--apply-all (steps)
-  "Apply text-scale of STEPS to every live buffer."
-  (dolist (buf (buffer-list))
-    (when (buffer-live-p buf)
-      (with-current-buffer buf
-        (text-scale-set steps)))))
+;; Faces that must stay at base height (do not scale with text).
+;; These form the fixed UI chrome: status bar, minibuffer, tab bar.
+(defvar my/zoom-pinned-faces
+  '(mode-line mode-line-inactive mode-line-active
+    minibuffer-prompt header-line
+    tab-bar tab-bar-tab tab-bar-tab-inactive)
+  "Faces pinned to `my/zoom-base-height' after every zoom operation.")
 
-(defun my/zoom--auto-apply ()
-  "Apply current zoom to newly opened/switched buffers."
-  (unless (= my/zoom-steps 0)
-    (text-scale-set my/zoom-steps)))
+(defun my/zoom-pin-ui ()
+  "Set pinned UI faces to base height so they don't scale with text."
+  (dolist (face my/zoom-pinned-faces)
+    (when (facep face)
+      (set-face-attribute face nil :height my/zoom-base-height))))
 
-;; Hook: apply zoom when a new buffer gets a major mode (covers find-file,
-;; new scratch buffers, magit, org-agenda, help, etc.)
-(add-hook 'after-change-major-mode-hook #'my/zoom--auto-apply)
+(defun my/zoom--apply (steps)
+  "Set global default face to base × 1.5^STEPS and re-pin UI faces."
+  (let ((new-h (max 80 (round (* my/zoom-base-height (expt 1.5 steps))))))
+    (set-face-attribute 'default nil :height new-h)
+    (my/zoom-pin-ui)
+    (message "Zoom %+d  ×%.2f  ≈%dpt"
+             steps (expt 1.5 steps) (/ new-h 10))))
+
+;; Capture base height after Doom finishes font setup.
+(add-hook 'doom-after-init-hook
+  (lambda ()
+    (let ((h (face-attribute 'default :height nil t)))
+      (when (and (integerp h) (> h 0))
+        (setq my/zoom-base-height h)))))
+
+;; Re-pin UI faces after any theme reload (Doom resets faces on theme change).
+(add-hook 'doom-load-theme-hook #'my/zoom-pin-ui)
 
 (defun my/zoom-in ()
-  "Zoom in one step (×1.5) across all buffers."
+  "Zoom in one step (×1.5) — all buffers, help, menus, everything."
   (interactive)
   (cl-incf my/zoom-steps)
-  (my/zoom--apply-all my/zoom-steps)
-  (message "Zoom +%d  (×%.2f  ≈%dpt)"
-           my/zoom-steps
-           (expt text-scale-mode-step my/zoom-steps)
-           (round (* 14 (expt text-scale-mode-step my/zoom-steps)))))
+  (my/zoom--apply my/zoom-steps))
 
 (defun my/zoom-out ()
-  "Zoom out one step (÷1.5) across all buffers."
+  "Zoom out one step (÷1.5) — all buffers."
   (interactive)
   (cl-decf my/zoom-steps)
-  (my/zoom--apply-all my/zoom-steps)
-  (message "Zoom %d  (×%.2f  ≈%dpt)"
-           my/zoom-steps
-           (expt text-scale-mode-step my/zoom-steps)
-           (round (* 14 (expt text-scale-mode-step my/zoom-steps)))))
+  (my/zoom--apply my/zoom-steps))
 
 (defun my/zoom-reset ()
-  "Reset all buffers to default text size. Saves current step for restore."
+  "Reset to default font size. Saves current level so SPC z z can restore."
   (interactive)
   (if (= my/zoom-steps 0)
       (message "Zoom: already at default")
     (setq my/zoom-saved-steps my/zoom-steps)
-    (my/zoom--apply-all 0)
+    (my/zoom--apply 0)
     (setq my/zoom-steps 0)
-    (message "Zoom reset to default  (was %+d — SPC z z to restore)"
-             my/zoom-saved-steps)))
+    (message "Zoom reset  (SPC z z to restore %+d)" my/zoom-saved-steps)))
 
 (defun my/zoom-restore ()
   "Restore zoom level saved before last reset."
   (interactive)
   (if (null my/zoom-saved-steps)
       (message "Zoom: nothing to restore")
-    (my/zoom--apply-all my/zoom-saved-steps)
+    (my/zoom--apply my/zoom-saved-steps)
     (setq my/zoom-steps my/zoom-saved-steps
-          my/zoom-saved-steps nil)
-    (message "Zoom restored: %+d  (×%.2f  ≈%dpt)"
-             my/zoom-steps
-             (expt text-scale-mode-step my/zoom-steps)
-             (round (* 14 (expt text-scale-mode-step my/zoom-steps))))))
+          my/zoom-saved-steps nil)))
 
 (map! :leader
       (:prefix ("z" . "zoom")
-       :desc "Zoom in  (×1.5/krok)"  "+" #'my/zoom-in
-       :desc "Zoom in  (×1.5/krok)"  "=" #'my/zoom-in
-       :desc "Zoom out (÷1.5/krok)"  "-" #'my/zoom-out
-       :desc "Reset na výchozí"       "0" #'my/zoom-reset
-       :desc "Restore předchozí zoom" "z" #'my/zoom-restore))
+       :desc "Zoom in  (×1.5)"     "+" #'my/zoom-in
+       :desc "Zoom in  (×1.5)"     "=" #'my/zoom-in
+       :desc "Zoom out (÷1.5)"     "-" #'my/zoom-out
+       :desc "Reset na výchozí"    "0" #'my/zoom-reset
+       :desc "Restore předchozí"   "z" #'my/zoom-restore))
 
 
 ;;; ============================================================