From 011488eaf1a6569c47a10eb7a9e48ea1e8155ff2 Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Fri, 25 Sep 2015 00:49:18 +0100
Subject: [PATCH] refs #271 C++ API wrapper for the X-Plane Plugin SDK's C API
 for drawing callbacks.

---
 src/xbus/drawable.h | 61 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 src/xbus/drawable.h

diff --git a/src/xbus/drawable.h b/src/xbus/drawable.h
new file mode 100644
index 000000000..66341dfe3
--- /dev/null
+++ b/src/xbus/drawable.h
@@ -0,0 +1,61 @@
+/* Copyright (C) 2015
+ * swift project Community / Contributors
+ *
+ * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
+ * directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
+ * including this file, may be copied, modified, propagated, or distributed except according to the terms
+ * contained in the LICENSE file.
+ */
+
+#ifndef BLACKSIM_XBUS_DRAWABLE_H
+#define BLACKSIM_XBUS_DRAWABLE_H
+
+//! \file
+
+#include <XPLMDisplay.h>
+
+namespace XBus
+{
+
+    /*!
+     * Class-based interface to X-Plane's drawing callback API.
+     */
+    class CDrawable
+    {
+    public:
+        //! Constructor.
+        CDrawable(XPLMDrawingPhase phase, bool before) : m_phase(phase), m_before(before) {}
+
+        //! Destructor.
+        ~CDrawable() { hide(); }
+
+        //! Register the draw callback.
+        virtual void show()
+        {
+            XPLMRegisterDrawCallback(callback, m_phase, m_before, static_cast<void*>(this));
+        }
+
+        //! Unregister the draw callback.
+        virtual void hide()
+        {
+            XPLMUnregisterDrawCallback(callback, m_phase, m_before, static_cast<void*>(this));
+        }
+
+    protected:
+        //! Callback to draw the thing.
+        virtual void draw() = 0;
+
+    private:
+        static int callback(XPLMDrawingPhase, int, void *refcon)
+        {
+            static_cast<CDrawable*>(refcon)->draw();
+            return 1;
+        }
+
+        const XPLMDrawingPhase m_phase;
+        const bool m_before;
+    };
+
+}
+
+#endif