configurable scrolling speed implemented

Architecture.md

@@ -362,9 +362,11 @@ replaces both together.
 
 **Plugin settings** (`vterm.sublime-settings`, read through the cached `settings()`
 handle): `auto_close`, `scrollback_history_size`, `honor_erase_scrollback`,
-`scroll_modifier`, `min_columns`, `max_columns`, `theme`, `ansi_colors`, `terminal`,
+`scroll_modifier`, `wheel_lines`, `min_columns`, `max_columns`, `theme`, `ansi_colors`, `terminal`,
 `parameters`, `debug`. `scroll_modifier` is the modifier that turns PgUp/PgDn and Up/Down
-into a scroll of the view — a page, a row — instead of a key for the app. `terminal` and
+into a scroll of the view — a page, a row — instead of a key for the app. `wheel_lines`
+is how many scroll lines one wheel notch sends the app (3, as iTerm2 delivers per notch;
+a trackpad converted to notches scrolls that much faster, so lower it). `terminal` and
 `parameters` name the external terminal spawned by *vterm: Open Terminal in Project
 Folder* (`%CWD%` in `parameters` becomes the project folder). ED 3 never touches the visible screen (as in
 xterm), and `honor_erase_scrollback` is off, so it does not drop the scrollback either:

README.md

@@ -56,7 +56,9 @@ wheel tick sends arrow keys (alternate scroll, as kitty/iTerm2 do — this is
 what scrolls Claude Code's fullscreen UI before it enables mouse reporting).
 Sublime raises no wheel event at all for the trackpad (sublime_text#1838): set
 a utility such as [LinearMouse](https://linearmouse.app/) to discrete scrolling
-for Sublime Text and it arrives as wheel notches like any other. While an app owns the
+for Sublime Text and it arrives as wheel notches like any other. A notch sends the
+app three scroll lines, as iTerm2 does; `wheel_lines` lowers that when a swipe
+scrolls too far. While an app owns the
 alternate screen the scrollback above it is folded away, kitty-style, and
 unfolds when the app leaves it.
 
@@ -154,7 +156,8 @@ instead), image protocols, Windows, panels.
 - Trackpad scrolling needs a helper on macOS: Sublime never delivers it to a
   plugin (sublime_text#1838), so set a utility such as
   [LinearMouse](https://linearmouse.app/) to discrete/linear scrolling for
-  Sublime Text. It then arrives as wheel notches and scrolls the app. Without
+  Sublime Text. It then arrives as wheel notches and scrolls the app, three
+  lines a notch unless `wheel_lines` says otherwise. Without
   one, the trackpad does nothing in a full-screen app; the mouse wheel,
   `shift+pageup/pagedown` and `shift+up/down` work regardless.
 

vterm.sublime-settings

@@ -15,6 +15,10 @@
     // null sends the keys to the app
     "scroll_modifier": "shift",
 
+    // scroll lines sent to the app per wheel notch (iTerm2 sends 3).
+    // A trackpad via LinearMouse makes many notches per swipe; 1 is calmer.
+    "wheel_lines": 1,
+
     "min_columns": 20,
     "max_columns": 500,
 

vterm/mouse.py

@@ -8,14 +8,12 @@ notches and take the path below.
 import sublime_plugin
 
 from .terminal import Terminal
+from .utils import settings
 
 # SGR button numbers for the wheel; 64 is the "scroll" bit plus direction
 WHEEL_UP = 64
 WHEEL_DOWN = 65
 
-# lines per wheel tick, as iTerm2 delivers per notch
-WHEEL_LINES = 3
-
 
 def send_scroll(terminal, up, lines, cell=None):
     """Report `lines` scroll lines to the app, or fake arrow keys on the alt screen.
@@ -105,7 +103,8 @@ class VtermScrollCommand(sublime_plugin.TextCommand):
         cell = None
         if terminal.screen.mouse_reporting_enabled() and event:
             cell = _event_to_cell(self.view, terminal, event, clamp=True)
-        send_scroll(terminal, up, WHEEL_LINES, cell)
+        lines = max(0, int(settings().get("wheel_lines", 3)))
+        send_scroll(terminal, up, lines, cell)
 
     def want_event(self):
         """Ask sublime for the wheel coordinates."""