From: Po Lu <luangruo@yahoo.com>
Date: Sat, 11 Dec 2021 10:30:01 +0000 (+0800)
Subject: Use window height to determine wheel event pixel deltas on XInput 2
X-Git-Tag: emacs-29.0.90~3604^2
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=d90be279958c093c4d3023ef553ea20508cf4c28;p=emacs.git

Use window height to determine wheel event pixel deltas on XInput 2

* src/xterm.c (handle_one_xevent): Use window height instead of
frame height to determine the height of a scroll unit.
---

diff --git a/src/xterm.c b/src/xterm.c
index 41aa2b268c1..f2129458e16 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -9990,6 +9990,8 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 		  {
 		    struct xi_scroll_valuator_t *val;
 		    double delta, scroll_unit;
+		    int scroll_height;
+		    Lisp_Object window;
 
 
 		    /* See the comment on top of
@@ -10056,7 +10058,19 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 							 xev->mods.effective);
 			  }
 
-			scroll_unit = pow (FRAME_PIXEL_HEIGHT (f), 2.0 / 3.0);
+			window = window_from_coordinates (f, xev->event_x,
+							  xev->event_y, NULL,
+							  false, false);
+
+			if (WINDOWP (window))
+			  scroll_height = XWINDOW (window)->pixel_height;
+			else
+			  /* EVENT_X and EVENT_Y can be outside the
+			     frame if F holds the input grab, so fall
+			     back to the height of the frame instead.  */
+			  scroll_height = FRAME_PIXEL_HEIGHT (f);
+
+			scroll_unit = pow (scroll_height, 2.0 / 3.0);
 
 			if (NUMBERP (Vx_scroll_event_delta_factor))
 			  scroll_unit *= XFLOATINT (Vx_scroll_event_delta_factor);