Initial commit, read more

This commit includes:

* Button
* TextLine
* TextBox
* TextField

It also includes these dependencies:

* Image
* BoundingBox

bounding_box.hpp

@@ -0,0 +1,65 @@
+/* Copyright: (c) Kayne Ruse 2013-2016
+ * 
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ * 
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ * 
+ * 1. The origin of this software must not be misrepresented; you must not
+ * claim that you wrote the original software. If you use this software
+ * in a product, an acknowledgment in the product documentation would be
+ * appreciated but is not required.
+ * 
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ * misrepresented as being the original software.
+ * 
+ * 3. This notice may not be removed or altered from any source
+ * distribution.
+*/
+#pragma once
+
+#include <type_traits>
+#include <algorithm>
+
+class BoundingBox {
+public:
+	//This is explicitly a POD
+	int x, y;
+	int w, h;
+
+	BoundingBox() = default;
+	BoundingBox(int i, int j): x(i), y(j), w(0), h(0) {};
+	BoundingBox(int i, int j, int k, int l): x(i), y(j), w(k), h(l) {};
+	~BoundingBox() = default;
+	BoundingBox& operator=(BoundingBox const&) = default;
+
+	int Size() {
+		return std::max(w*h,0);
+	}
+
+	bool CheckOverlap(BoundingBox rhs) {
+		return !(
+			x >= rhs.x + rhs.w ||
+			y >= rhs.y + rhs.h ||
+			rhs.x >= x + w ||
+			rhs.y >= y + h);
+	}
+
+	BoundingBox CalcOverlap(BoundingBox rhs) {
+		if (!CheckOverlap(rhs)) {
+			return {0, 0, 0, 0};
+		}
+		BoundingBox ret;
+		ret.x = std::max(x, rhs.x);
+		ret.y = std::max(y, rhs.y);
+		ret.w = std::min(x+w, rhs.x+rhs.w) - ret.x;
+		ret.h = std::min(y+h, rhs.y+rhs.h) - ret.y;
+		return ret;
+	}
+};
+
+//This is explicitly a POD
+static_assert(std::is_pod<BoundingBox>::value, "BoundingBox is not a POD");