config: add entry for scroll-to-bottom (#8412)

Related #8408

(EDIT @mitchellh: Removed "Fixes" to avoid closing)

src/Surface.zig

@@ -272,6 +272,7 @@ const DerivedConfig = struct {
     title_report: bool,
     links: []Link,
     link_previews: configpkg.LinkPreviews,
+    scroll_to_bottom: configpkg.Config.ScrollToBottom,
 
     const Link = struct {
         regex: oni.Regex,
@@ -340,6 +341,7 @@ const DerivedConfig = struct {
             .title_report = config.@"title-report",
             .links = links,
             .link_previews = config.@"link-previews",
+            .scroll_to_bottom = config.@"scroll-to-bottom",
 
             // Assignments happen sequentially so we have to do this last
             // so that the memory is captured from allocs above.
@@ -2280,7 +2282,8 @@ pub fn keyCallback(
             try self.setSelection(null);
         }
 
-        try self.io.terminal.scrollViewport(.{ .bottom = {} });
+        if (self.config.scroll_to_bottom.keystroke) try self.io.terminal.scrollViewport(.bottom);
+
         try self.queueRender();
     }
 

src/config/Config.zig

@@ -767,6 +767,22 @@ palette: Palette = .{},
 /// the mouse is shown again when a new window, tab, or split is created.
 @"mouse-hide-while-typing": bool = false,
 
+/// When to scroll the surface to the bottom. The format of this is a list of
+/// options to enable separated by commas. If you prefix an option with `no-`
+/// then it is disabled. If you omit an option, its default value is used.
+///
+/// Available options:
+///
+/// - `keystroke` If set, scroll the surface to the bottom when the user
+///   presses a key that results in data being sent to the PTY (basically
+///   anything but modifiers or keybinds that are processed by Ghostty).
+///
+/// - `output` If set, scroll the surface to the bottom if there is new data
+///   to display. (Currently unimplemented.)
+///
+/// The default is `keystroke, no-output`.
+@"scroll-to-bottom": ScrollToBottom = .default,
+
 /// Determines whether running programs can detect the shift key pressed with a
 /// mouse click. Typically, the shift key is used to extend mouse selection.
 ///
@@ -8031,6 +8047,14 @@ pub const WindowPadding = struct {
     }
 };
 
+/// See scroll-to-bottom
+pub const ScrollToBottom = packed struct {
+    keystroke: bool = true,
+    output: bool = false,
+
+    pub const default: ScrollToBottom = .{};
+};
+
 test "parse duration" {
     inline for (Duration.units) |unit| {
         var buf: [16]u8 = undefined;