perf: Don't do unneeded calculation

sideline.el

@@ -392,11 +392,11 @@ calculate to the right side."
   ;; This is smart since we add up the string size before the calculation!
   (setq str-len (+ str-len opposing-str-len))
   ;; Start the calculation!
-  (let* ((column-start (sideline--window-hscroll))
-         (win-width (sideline--window-width))
-         (pos-end (max (sideline--line-width) column-start)))
+  (when-let* ((win-width (sideline--render-data :win-width))
+              ((<= str-len win-width))
+              (column-start (sideline--render-data :hscroll))
+              (pos-end (max (sideline--line-width) column-start)))
     (cond
-     ((> str-len win-width) nil)
      (on-left
       (let ((pos-first (save-excursion (back-to-indentation) (current-column))))
         (cond ((<= str-len (- pos-first column-start))
@@ -559,7 +559,7 @@ FACE, NAME, ON-LEFT, and ORDER for details."
        (len-title (sideline--str-len title))
        (data (sideline--find-line len-title on-left order))
        (pos-start (nth 0 data)) (pos-end (nth 1 data)) (occ-pt (nth 2 data))
-       (offset (- 0 (sideline--window-hscroll)))
+       (offset (- 0 (sideline--render-data :hscroll)))
        (str (concat
              (unless on-left
                (propertize " "
@@ -663,7 +663,9 @@ If argument ON-LEFT is non-nil, it will align to the left instead of right."
     (unless (funcall sideline-inhibit-display-function)
       (setq sideline--render-data
             `( :eol ,(sideline--window-end)
-               :bol ,(window-start)))
+               :bol ,(window-start)
+               :hscroll ,(sideline--window-hscroll)
+               :win-width ,(sideline--window-width)))
       (run-hooks 'sideline-pre-render-hook)
       (sideline--render-backends sideline-backends-left t)
       (sideline--render-backends sideline-backends-right nil)