horizontal scroll for file panes (terminals wrap at pty width — nothing to scroll): pane.hscroll cuts content columns after the lineno gutter in bodyText (post edit-splice, so typed runs shift with the text), no scrollbar. Drivers: horizontal wheel (new wheel_left/right Mouse.Buttons, SGR 66/67 via vaxis on the tty, SDL wheel.x on the gui, ±4 cols, clamped at 0, right overscroll allowed) and keyboard movement — ensureCursorVisible grew the horizontal mirror of the scrolloff reconcile, so $ pulls the view right with 3 columns of margin and 0 reels it home; the wheel never moves the cursor. Shifted alongside: syntax recolor pass, modal cursor paint (hidden when off-view), vsel highlight, click->content-col mapping, cursorWordSel. Byte columns like the rest of the file-pane code. New hscroll.snap golden: wheel shift with fixed gutter, left clamp, $ margin follow, 0 home. 30/30.

1 files changed, 10 insertions, 2 deletions

diff --git a/src/gui.zig b/src/gui.zig
index 15631efa..60d9501f 100644
--- a/src/gui.zig
+++ b/src/gui.zig
@@ -1080,6 +1080,8 @@ const StdinFeed = struct {
                         .right => .right,
                         .wheel_up => .wheel_up,
                         .wheel_down => .wheel_down,
+                        .wheel_left => .wheel_left,
+                        .wheel_right => .wheel_right,
                         .none => .none,
                         else => null,
                     };
@@ -1266,16 +1268,22 @@ fn dispatch(g: *Gui, core: *pardes.Pardes, sev: *const c.SDL_Event) void {
         },
         c.SDL_EVENT_MOUSE_WHEEL => {
             const w = sev.wheel;
-            if (w.y == 0) return;
+            if (w.y == 0 and w.x == 0) return;
             g.mouse_x = w.mouse_x;
             g.mouse_y = w.mouse_y;
             const mc = mouseCell(g, core, w.mouse_x, w.mouse_y);
-            core.update(.{ .mouse = .{
+            if (w.y != 0) core.update(.{ .mouse = .{
                 .button = if (w.y > 0) .wheel_up else .wheel_down,
                 .kind = .press,
                 .col = mc.col,
                 .row = mc.row,
             } });
+            if (w.x != 0) core.update(.{ .mouse = .{
+                .button = if (w.x > 0) .wheel_right else .wheel_left,
+                .kind = .press,
+                .col = mc.col,
+                .row = mc.row,
+            } });
         },
         c.SDL_EVENT_FINGER_DOWN, c.SDL_EVENT_FINGER_MOTION, c.SDL_EVENT_FINGER_UP, c.SDL_EVENT_FINGER_CANCELED => {
             const f = sev.tfinger;