padding needs to be sent to termio

src/Window.zig

@@ -586,7 +586,8 @@ fn sizeCallback(window: glfw.Window, width: i32, height: i32) void {
     _ = win.io_thread.mailbox.push(.{
         .resize = .{
             .grid_size = win.grid_size,
-            .screen_size = screen_size.subPadding(win.padding),
+            .screen_size = screen_size,
+            .padding = win.padding,
         },
     }, .{ .forever = {} });
     win.io_thread.wakeup.send() catch {};

src/termio/Exec.zig

@@ -231,13 +231,16 @@ pub fn resize(
     self: *Exec,
     grid_size: renderer.GridSize,
     screen_size: renderer.ScreenSize,
+    padding: renderer.Padding,
 ) !void {
+    const padded_size = screen_size.subPadding(padding);
+
     // Update the size of our pty
     try self.pty.setSize(.{
         .ws_row = @intCast(u16, grid_size.rows),
         .ws_col = @intCast(u16, grid_size.columns),
-        .ws_xpixel = @intCast(u16, screen_size.width),
-        .ws_ypixel = @intCast(u16, screen_size.height),
+        .ws_xpixel = @intCast(u16, padded_size.width),
+        .ws_ypixel = @intCast(u16, padded_size.height),
     });
 
     // Update our cached grid size

src/termio/Thread.zig

@@ -172,7 +172,7 @@ fn drainMailbox(self: *Thread) !void {
 
             log.debug("mailbox message={}", .{message});
             switch (message) {
-                .resize => |v| try self.impl.resize(v.grid_size, v.screen_size),
+                .resize => |v| try self.impl.resize(v.grid_size, v.screen_size, v.padding),
                 .write_small => |v| try self.impl.queueWrite(v.data[0..v.len]),
                 .write_stable => |v| try self.impl.queueWrite(v),
                 .write_alloc => |v| {

src/termio/message.zig

@@ -12,8 +12,16 @@ const terminal = @import("../terminal/main.zig");
 pub const Message = union(enum) {
     /// Resize the window.
     resize: struct {
+        /// The grid size for the given screen size with padding applied.
         grid_size: renderer.GridSize,
+
+        /// The full screen (drawable) size. This does NOT include padding.
+        /// This should be sent on to the renderer.
         screen_size: renderer.ScreenSize,
+
+        /// The padding, so that the terminal implementation can subtract
+        /// this to send to the pty.
+        padding: renderer.Padding,
     },
 
     /// Write where the data fits in the union.