Ingame GUI
Basic building blocks of ingame GUI are rectangle components. Everything in GUI must have this component.
Rectangle component is used only to position elements in GUI. Each rectable is defined by 4 edges - top, right, bottom and left. Each edge's position is defined by two numbers, relative position to its parent's rectangle and absolute offset in points. You can use following formula to get the left edge's x coordinate:
left = parent_left + parent_width * left_relative + left_points
