UTF-8 mouse reporting

src/Window.zig

@@ -822,15 +822,9 @@ fn mouseReport(
         .any => {},
     }
 
-    switch (self.terminal.modes.mouse_format) {
-        .x10 => {
     // This format reports X/Y
     const pos = self.cursorPosToPixels(unscaled_pos);
     const viewport_point = self.posToViewport(pos.xpos, pos.ypos);
-            if (viewport_point.x > 222 or viewport_point.y > 222) {
-                log.info("X10 mouse format can only encode X/Y up to 223", .{});
-                return;
-            }
 
     // For button events, we only report if we moved cells
     if (self.terminal.modes.mouse_event == .button or
@@ -843,6 +837,7 @@ fn mouseReport(
         self.mouse.event_point = viewport_point;
     }
 
+    // Get the code we'll actually write
     const button_code: u8 = code: {
         var acc: u8 = if (action == .release or button == null)
             3
@@ -869,6 +864,13 @@ fn mouseReport(
         break :code acc;
     };
 
+    switch (self.terminal.modes.mouse_format) {
+        .x10 => {
+            if (viewport_point.x > 222 or viewport_point.y > 222) {
+                log.info("X10 mouse format can only encode X/Y up to 223", .{});
+                return;
+            }
+
             // + 1 below is because our x/y is 0-indexed and proto wants 1
             var buf = [_]u8{ '\x1b', '[', 'M', 0, 0, 0 };
             buf[3] = 32 + button_code;
@@ -877,6 +879,24 @@ fn mouseReport(
             try self.queueWrite(&buf);
         },
 
+        .utf8 => {
+            // Maximum of 12 because at most we have 2 fully UTF-8 encoded chars
+            var buf: [12]u8 = undefined;
+            buf[0] = '\x1b';
+            buf[1] = '[';
+            buf[2] = 'M';
+
+            // The button code will always fit in a single u8
+            buf[3] = 32 + button_code;
+
+            // UTF-8 encode the x/y
+            var i: usize = 4;
+            i += try std.unicode.utf8Encode(@intCast(u21, 32 + viewport_point.x + 1), buf[i..]);
+            i += try std.unicode.utf8Encode(@intCast(u21, 32 + viewport_point.y + 1), buf[i..]);
+
+            try self.queueWrite(buf[0..i]);
+        },
+
         else => @panic("TODO"),
     }
 }
@@ -1454,6 +1474,8 @@ pub fn setMode(self: *Window, mode: terminal.Mode, enabled: bool) !void {
         .mouse_event_button => self.terminal.modes.mouse_event = if (enabled) .button else .none,
         .mouse_event_any => self.terminal.modes.mouse_event = if (enabled) .any else .none,
 
+        .mouse_format_utf8 => self.terminal.modes.mouse_format = if (enabled) .utf8 else .x10,
+
         else => if (enabled) log.warn("unimplemented mode: {}", .{mode}),
     }
 }

src/terminal/Terminal.zig

@@ -93,9 +93,9 @@ pub const MouseEvents = enum(u3) {
 /// These are all mutually exclusive (hence in a single enum).
 pub const MouseFormat = enum(u3) {
     x10 = 0,
+    utf8 = 1, // 1005
 
     // TODO:
-    utf8 = 1, // 1005
     sgr = 2, // 1006
     urxvt = 3, // 1015
     sgr_pixels = 4, // 1016

src/terminal/ansi.zig

@@ -80,6 +80,9 @@ pub const Mode = enum(u16) {
     /// to track mouse movement.
     mouse_event_any = 1003,
 
+    /// Report mouse position in the utf8 format to support larger screens.
+    mouse_format_utf8 = 1005,
+
     /// Alternate screen mode with save cursor and clear on enter.
     alt_screen_save_cursor_clear_enter = 1049,