vz: Fix scrollbar issue with runtime swizzle

pkg/driver/vz/scrollbar_fix_darwin.go

@@ -0,0 +1,16 @@
+// SPDX-FileCopyrightText: Copyright The Lima Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build darwin
+
+// This file includes scrollbar_fix_darwin.m via cgo.
+// See that file for documentation on why this patch is needed.
+
+package vz
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework Cocoa -lobjc
+#include "scrollbar_fix_darwin.m"
+*/
+import "C"

pkg/driver/vz/scrollbar_fix_darwin.m

@@ -0,0 +1,44 @@
+// SPDX-FileCopyrightText: Copyright The Lima Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// scrollbar_fix_darwin.m - Runtime patch to disable scrollbars on VZ display window
+//
+// The Code-Hex/vz library wraps VZVirtualMachineView in an NSScrollView with
+// scrollbars hardcoded to YES (for their zoom feature). This causes ~16px of
+// the VM display to be cut off by scrollbar gutters.
+//
+// This file uses Objective-C method swizzling to intercept NSScrollView's
+// setDocumentView: method and disable scrollbars when the document view is
+// a VZVirtualMachineView.
+//
+// This is a temporary workaround until Code-Hex/vz adds a configuration option
+// to disable scrollbars. See: https://github.com/Code-Hex/vz/issues/XXX
+
+#import <Cocoa/Cocoa.h>
+#import <objc/runtime.h>
+
+// Store original implementation pointer
+static IMP original_setDocumentView = NULL;
+
+// Patched implementation that disables scrollbars for VZ views
+static void patched_setDocumentView(id self, SEL _cmd, NSView *view) {
+    // Call original implementation first
+    ((void (*)(id, SEL, NSView *))original_setDocumentView)(self, _cmd, view);
+
+    // If the document view is a VZVirtualMachineView, disable scrollbars
+    // The scrollbars cause the VM display to be cut off by ~16px
+    if (view != nil && [view isKindOfClass:NSClassFromString(@"VZVirtualMachineView")]) {
+        [(NSScrollView *)self setHasVerticalScroller:NO];
+        [(NSScrollView *)self setHasHorizontalScroller:NO];
+    }
+}
+
+// Constructor attribute ensures this runs before main()
+// This patches NSScrollView before Code-Hex/vz creates any windows
+__attribute__((constructor))
+static void patchNSScrollViewForVZ(void) {
+    Method m = class_getInstanceMethod([NSScrollView class], @selector(setDocumentView:));
+    if (m != NULL) {
+        original_setDocumentView = method_setImplementation(m, (IMP)patched_setDocumentView);
+    }
+}