Add core library and element classes for Basalt framework

src/elements/Button.lua

@@ -0,0 +1,29 @@
+local VisualElement = require("elements/VisualElement")
+local getCenteredPosition = require("libraries/utils").getCenteredPosition
+
+local Button = setmetatable({}, VisualElement)
+Button.__index = Button
+
+Button.defineProperty(Button, "text", {default = "Button", type = "string"})
+Button.listenTo(Button, "mouse_click")
+
+---@diagnostic disable-next-line: duplicate-set-field
+function Button.new(id, basalt)
+    local self = setmetatable({}, Button):__init()
+    self:init(id, basalt)
+    self.set("type", "Button")
+    self.set("width", 10)
+    self.set("height", 3)
+    self.set("z", 5)
+    return self
+end
+
+---@diagnostic disable-next-line: duplicate-set-field
+function Button:render()
+    VisualElement.render(self)
+    local text = self.get("text")
+    local xO, yO = getCenteredPosition(text, self.get("width"), self.get("height"))
+    self:textFg(xO, yO, text, self.get("foreground"))
+end
+
+return Button