refactor(system-utils): remove the *scratch* background tint

I dropped the buffer-local face remap that lightened the *scratch* background 5% above the theme default. Scratch now uses the plain theme background like every other buffer. The startup hook still moves the cursor to end-of-scratch. Only the tint call, its two helpers, the defcustom, the color require, and the now-orphaned test go.

2 files changed, 2 insertions, 59 deletions

diff --git a/modules/system-utils.el b/modules/system-utils.el
index b3e038ef0..7cf958674 100644
--- a/modules/system-utils.el
+++ b/modules/system-utils.el
@@ -157,39 +157,12 @@ detached from Emacs."
 ;; Set scratch buffer to org-mode
 (setopt initial-major-mode 'org-mode)
 
-;; Tint the *scratch* background a shade lighter than the default so it reads
-;; as the scratch buffer at a glance.  Buffer-local face remap, recomputed from
-;; whatever theme is loaded.
-(require 'color)
-
-(defcustom cj/scratch-background-lighten 5
-  "Percent to lighten the *scratch* background above the default background.
-Aesthetic; tune to taste."
-  :type 'integer
-  :group 'convenience)
-
-(defun cj/--scratch-lightened-background (bg)
-  "Return BG lightened by `cj/scratch-background-lighten' percent.
-Return nil when BG is not a usable color string (e.g. `unspecified')."
-  (when (and (stringp bg) (color-name-to-rgb bg))
-    (color-lighten-name bg cj/scratch-background-lighten)))
-
-(defun cj/scratch-apply-background ()
-  "Remap the *scratch* buffer background a shade lighter than the default."
-  (when (get-buffer "*scratch*")
-    (with-current-buffer "*scratch*"
-      (let ((lighter (cj/--scratch-lightened-background
-                      (face-attribute 'default :background nil t))))
-        (when lighter
-          (face-remap-add-relative 'default :background lighter))))))
-
-;; Move cursor to end of scratch buffer on startup, and tint its background
+;; Move cursor to end of scratch buffer on startup
 (add-hook 'emacs-startup-hook
           (lambda ()
             (when (get-buffer "*scratch*")
               (with-current-buffer "*scratch*"
-                (goto-char (point-max))))
-            (cj/scratch-apply-background)))
+                (goto-char (point-max))))))
 
 ;;; --------------------------------- Dictionary --------------------------------
 
diff --git a/tests/test-system-utils-scratch-background.el b/tests/test-system-utils-scratch-background.el
deleted file mode 100644
index 422590f4b..000000000
--- a/tests/test-system-utils-scratch-background.el
+++ /dev/null
@@ -1,30 +0,0 @@
-;;; test-system-utils-scratch-background.el --- Tests for the scratch tint -*- lexical-binding: t; -*-
-
-;;; Commentary:
-;; cj/--scratch-lightened-background lightens the default background by a
-;; tunable percent for the *scratch* buffer's buffer-local face remap.  The
-;; colour arithmetic (color-lighten-name -> color-name-to-rgb) is
-;; display-dependent and returns zeros under --batch, so the actual lightening
-;; is verified live in the daemon; here we cover the display-independent
-;; contract: a usable colour string yields a string, junk yields nil.
-
-;;; Code:
-
-(require 'ert)
-(require 'color)
-(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
-(require 'system-utils)
-
-(ert-deftest test-system-utils-scratch-lightened-background-returns-string ()
-  "Normal: a valid hex colour yields a colour string (not nil)."
-  (let ((cj/scratch-background-lighten 5))
-    (should (stringp (cj/--scratch-lightened-background "#100f0f")))))
-
-(ert-deftest test-system-utils-scratch-lightened-background-bad-input ()
-  "Error: non-colour input yields nil rather than signalling."
-  (should (null (cj/--scratch-lightened-background nil)))
-  (should (null (cj/--scratch-lightened-background 'unspecified)))
-  (should (null (cj/--scratch-lightened-background "not-a-color"))))
-
-(provide 'test-system-utils-scratch-background)
-;;; test-system-utils-scratch-background.el ends here