[nongnu] elpa/scroll-on-drag 9836df8c62 1/2: Add scroll-on-drag-mode-line-format to optionally override the mode-line

[ELPA Syncer]

branch: elpa/scroll-on-drag
commit 9836df8c628d2b496ca62cf37d3a029af819bc11
Author: Campbell Barton <ideasman42@gmail.com>
Commit: Campbell Barton <ideasman42@gmail.com>

    Add scroll-on-drag-mode-line-format to optionally override the mode-line
    
    This can be used to prevent complex mode-lines interfering with
    scrolling performance.
---
 readme.rst        |  4 ++++
 scroll-on-drag.el | 22 ++++++++++++++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/readme.rst b/readme.rst
index 070b5d98c4..5b9f0bfe34 100644
--- a/readme.rst
+++ b/readme.rst
@@ -93,3 +93,7 @@ While the defaults seem to work well, these values can be 
customized.
 ``scroll-on-drag-follow-mouse``
    When non-nil, scroll the window under the mouse cursor (even when it's not 
active)
    returning focus on completion.
+``scroll-on-drag-mode-line-format``: nil
+   When non-nil, use this value for the ``mode-line-format`` while scrolling.
+   This can be used to temporarily override the mode-line while scrolling.
+   It can also help to avoid overly complex mode-lines from slowing down 
scrolling.
diff --git a/scroll-on-drag.el b/scroll-on-drag.el
index 2df1bfca61..19e466921e 100644
--- a/scroll-on-drag.el
+++ b/scroll-on-drag.el
@@ -72,6 +72,13 @@
   "Scroll the window under the mouse cursor (instead of the current active 
window)."
   :type 'boolean)
 
+(defcustom scroll-on-drag-mode-line-format nil
+  "The `mode-line-format' to use or nil to leave the `mode-line-format' 
unchanged.
+
+This can be useful to use a simplified or event disabling the mode-line
+while scrolling, as a complex mode-line can interfere with smooth scrolling."
+  :type '(choice (const nil) string))
+
 (defcustom scroll-on-drag-pre-hook nil
   "List of functions to be called when `scroll-on-drag' starts."
   :type 'hook)
@@ -476,14 +483,25 @@ This requires a separate code path to run pre/post logic."
      (t
       (scroll-on-drag--impl)))))
 
+(defun scroll-on-drag--impl-with-mode-line-format ()
+  "Call `mode-line-format' with mode-line override."
+
+  (cond
+   (scroll-on-drag-mode-line-format
+    (prog1 (let ((mode-line-format scroll-on-drag-mode-line-format))
+             (scroll-on-drag--impl-with-evil-mode-workaround))
+      (force-mode-line-update)))
+   (t
+    (scroll-on-drag--impl-with-evil-mode-workaround))))
+
 (defun scroll-on-drag--impl-with-window (scroll-win)
   "Scroll on drag function that takes an optional SCROLL-WIN."
   (cond
    (scroll-win
     (with-selected-window scroll-win
-      (scroll-on-drag--impl-with-evil-mode-workaround)))
+      (scroll-on-drag--impl-with-mode-line-format)))
    (t
-    (scroll-on-drag--impl-with-evil-mode-workaround))))
+    (scroll-on-drag--impl-with-mode-line-format))))
 
 (defun scroll-on-drag (&optional event)
   "Main scroll on drag function.