Use text scale in calculating visible window height (fix emacs-evil#1497

)

evil-commands.el

@@ -1043,7 +1043,7 @@ If the scroll count is zero the command scrolls half the screen."
     (when (= (point-min) (line-beginning-position))
       (signal 'beginning-of-buffer nil))
     (when (zerop count)
-      (setq count (/ (window-body-height) 2)))
+      (setq count (/ (evil-window-visible-height) 2)))
     (let ((xy (evil-posn-x-y (posn-at-point))))
       (condition-case nil
           (progn
@@ -1067,7 +1067,7 @@ If the scroll count is zero the command scrolls half the screen."
     (setq evil-scroll-count count)
     (when (eobp) (signal 'end-of-buffer nil))
     (when (zerop count)
-      (setq count (/ (window-body-height) 2)))
+      (setq count (/ (evil-window-visible-height) 2)))
     ;; BUG #660: First check whether the eob is visible.
     ;; In that case we do not scroll but merely move point.
     (if (<= (point-max) (window-end))

evil-common.el

@@ -3980,6 +3980,18 @@ PROPERTIES is a property-list which supports the following properties:
          (evil-motion-state))
        (switch-to-buffer-other-window buf))))
 
+;;; Window
+
+(defun evil-window-visible-height (&optional window)
+  "The visible height of WINDOW in lines.
+
+If no WINDOW is specified, use the selected one."
+  (let ((window (or window (selected-window))))
+    (save-window-excursion
+      (select-window window)
+      (let ((current-scale (expt text-scale-mode-step text-scale-mode-amount)))
+        (round (/ (window-body-height) current-scale))))))
+
 (provide 'evil-common)
 
 ;;; evil-common.el ends here