refac(org segment): make max-length calculation dynamic

Calculation is now linked to the available space.

This removes `whale-lien-segments-org-max-heading-length`.

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Removed
 
 - `dir-locals.el` is no longer tracked.
+- Custom variable `whale-line-segments-org-max-length`.
 
 ### Changed
 

README.org

@@ -85,7 +85,6 @@ will need to call =whale-line-rebuild=.
   (whale-line-segments-org-ellispis "…")
   (whale-line-segments-org-elision "*")
   (whale-line-segments-org-max-count 2)
-  (whale-line-segments-org-max-heading-length 12)
 
   ;; Specs for used icons.
   (whale-line-iconify-specs '((project . (:name "package" :font octicon :face whale-line-emphasis))

test/whale-line-segments-test.el

@@ -367,11 +367,30 @@
 (ert-deftest org--maybe-truncate--skips ()
   (should (string= "testing" (whale-line-segments--org--maybe-truncate "testing" 'success 7))))
 
-(ert-deftest org--maybe-truncate--obeys-min ()
-  (bydi ((:mock whale-line--space :return -123))
+(ert-deftest org--max-length--obeys-min ()
+  (bydi ((:mock whale-line--space :return -123)
+         (:mock window-font-width :return 10))
     (should (eq whale-line-segments--org--min-length
                 (whale-line-segments--org--max-length)))))
 
+(ert-deftest org--max-length--obeys-max ()
+  (let ((whale-line-segments-org-max-count 3)
+        (whale-line-segments--org--max-length 12)
+        (whale-line-segments--org--min-length 4))
+
+    (bydi ((:mock whale-line--space :return 40)
+           (:mock window-font-width :return 1))
+      (should (eq 12 (whale-line-segments--org--max-length))))))
+
+(ert-deftest org--max-length--reduces-max ()
+  (let ((whale-line-segments-org-max-count 3)
+        (whale-line-segments--org--max-length 12)
+        (whale-line-segments--org--min-length 3))
+
+    (bydi ((:mock whale-line--space :return 32)
+           (:mock window-font-width :return 1))
+      (should (eq 10 (whale-line-segments--org--max-length))))))
+
 (ert-deftest org--get-next-heading ()
   (let ((org-level-faces '(red green blue orange)))
 

whale-line-segments.el

@@ -72,11 +72,6 @@ to 2, only the 3rd level is elided."
   :group 'whale-line-segments
   :type 'integer)
 
-(defcustom whale-line-segments-org-max-heading-length 12
-  "The max length of a heading after which it will be truncated."
-  :group 'whale-line-segments
-  :type 'integer)
-
 ;;; -- Segments
 
 (declare-function image-mode-window-get "ext:image-mode.el")
@@ -479,6 +474,7 @@ Returns nil if not checking or if no errors were found."
 (declare-function org-up-heading-safe "ext:org.el")
 
 (defvar wls--org--min-length 4)
+(defvar wls--org--max-length 24)
 
 (defun wls--org--maybe-truncate (heading face max-len)
   "Maybe truncate HEADING depending on MAX-LEN.
@@ -503,13 +499,13 @@ Use FACE for the ellipsis glyph."
 
 (defun wls--org--max-length ()
   "Check if we're in a low space environment."
-  (let ((space (whale-line--space)))
+  (let* ((space (max 1 (whale-line--space)))
+         (width (/ space (window-font-width))))
 
-    (if (> space 0)
-        (max wls--org--min-length
-             (/ wls-org-max-heading-length
-                (max (/ 300 space) 1)))
-      wls--org--min-length)))
+    (if (> width (* wls-org-max-count wls--org--max-length))
+        wls--org--max-length
+      (min wls--org--max-length
+           (max wls--org--min-length (/ width wls-org-max-count))))))
 
 (defun wls--org--collect-headings ()
   "Collect headings until it's no longer safe."