--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ui/ui/win32.h	Wed Oct 08 09:46:23 2025 +0200
@@ -0,0 +1,66 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2025 Olaf Wintermann. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef UI_WIN32_H
+#define UI_WIN32_H
+
+#include <Windows.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define UIEXPORT __declspec(dllexport)
+
+typedef struct W32WidgetClass W32WidgetClass;
+typedef struct W32Widget W32Widget;
+typedef struct W32Size W32Size;
+
+struct W32Size {
+    int width;
+    int height;
+};
+
+struct W32WidgetClass {
+    void (*show)(W32Widget *widget, BOOLEAN show);
+    void (*enable)(W32Widget *widget, BOOLEAN enable);
+    W32Size (*get_preferred_size)(W32Widget *widget);
+    void (*destroy)(W32Widget *widget);
+};
+
+struct W32Widget {
+    W32WidgetClass *wclass;
+    HWND hwnd;
+    void *userdata;
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* UI_WIN32_H */