added ImageLock RAII class for SDL Surface locking

ImageLock.cpp

@@ -0,0 +1,20 @@
+//
+// ImageLock.cpp
+// libscgui
+//
+// Created by Bob Polis at 2020-10-24
+// Copyright (c) 2020 SwiftCoder. All rights reserved.
+//
+
+#include "ImageLock.hpp"
+#include "Image.hpp"
+
+using namespace sc::gui;
+
+ImageLock::ImageLock(const Image& image) : _image {image} {
+    SDL_LockSurface(image.surface());
+}
+
+ImageLock::~ImageLock() {
+    SDL_UnlockSurface(_image.surface());
+}

ImageLock.hpp

@@ -0,0 +1,32 @@
+//
+// ImageLock.hpp
+// libscgui
+//
+// Created by Bob Polis at 2020-10-24
+// Copyright (c) 2020 SwiftCoder. All rights reserved.
+//
+
+#ifndef _ImageLock_H_
+#define _ImageLock_H_
+
+namespace sc {
+    namespace gui {
+        class Image;
+
+        class ImageLock {
+            public:
+                ImageLock(const Image& image);
+                ~ImageLock();
+
+                ImageLock(const ImageLock&) = delete;
+                ImageLock& operator=(const ImageLock&) = delete;
+                ImageLock(ImageLock&&) = delete;
+                ImageLock& operator=(ImageLock&&) = delete;
+
+            private:
+                const Image& _image;
+        };
+    }
+}
+
+#endif // _ImageLock_H_