added Rect class

code/rect.lua

@@ -0,0 +1,66 @@
+-- based of of plan9's Rectangle struct
+-- rect.max is not counted as "in" the rectangle
+Rect = {}
+Rect.__index = Rect
+
+function Rect:fromPoints(pt1, pt2)
+	local o = { min = pt1, max = pt2 }
+	setmetatable(o, self)
+end
+
+function Rect:fromCoords(x1, y1, x2, y2)
+	return Rect:fromPoints(Point:new(x1, y1), Point:new(x2, y2))
+end
+
+-- clone refers to a deep copy
+function Rect:clone()
+	return Rect:fromCoods(self.min.x, self.min.y, self.max.x, self.max.y)
+end
+
+-- make sure min and max refer to the correct corners
+-- acts in place, returns self
+function Rect:fix()
+	if self.min.x > self.max.x then
+		self.min.x, self.max.x = self.max.x, self.min.x
+	end
+	if self.min.y > self.max.y then
+		self.min.y, self.max.y = self.max.y, self.min.y
+	end
+end
+
+function Rect:width()
+	return self.max.x - self.min.x
+end
+
+function Rect:height()
+	return self.max.y - self.min.y
+end
+
+function Rect:size()
+	return Point:new(self:width(), self:height())
+end
+
+function Rect:__add(pt)
+	return Rect:fromPoints(self.min + pt, self.max + pt)
+end
+
+function Rect:corners()
+	return {
+		self.min:copy(), -- top left
+		Point:new(self.max.x, self.min.y), -- top right
+		Point:new(self.min.x, self.max.y), -- bottom left
+		self.max:copy(), -- bottom right
+	}
+end
+
+function Rect:containsPoint(pt)
+	return self.min.x < pt.x and
+		self.min.y < pt.y and
+		pt.x < self.max.x and
+		pt.y < self.max.y
+end
+
+function Rect:overlapsRect(other)
+		return self.min.x<other.max.x and self.min.x<other.max.x and
+	       self.min.y<other.max.y and self.min.y<other.max.y
+end