crystal.Container

Base class for UI elements which can contain multiple child elements.

Some example container classes are HorizontalList, VerticalList and Overlay.

Constructor

crystal.Container:new(joint_class)

The joint_class parameter must be a class inheriting from Joint.

Methods

Name	Description
add_child	Adds a child element to this container.
arrange_children	Computes and sets the relative positions of child elements.
child	Returns a child element by index.
children	Returns the list of child elements.
remove_child	Removes a child element.

Examples

Using an existing Container class:

local title_screen = crystal.Overlay:new();
local background = title_screen:add_child(crystal.Image:new());
local logo = title_screen:add_child(crystal.Image:new(crystal.assets.get("logo.png")));
background:set_alignment("stretch", "stretch");
logo:set_alignment("center", "center");

Implementing your own Container class:

local MyContainerJoint = Class("MyContainerJoint", crystal.Joint);

MyContainerJoint.init = function(self)
  -- Joint default setup goes here eg. `self.margin = 0;`
end

local MyContainer = Class("MyContainer", crystal.Container);

MyContainer.init = function(self)
  MyContainer.super.init(self, MyContainerJoint);
end

MyContainer.arrange_children = function(self)
  -- Layout logic goes here
end