crystal.Wrapper

Base class for UI elements which can contain one child element.

Some example wrapper classes are Widget and Painter.

Constructor

crystal.Wrapper:new(joint_class)

The joint_class parameter must be a class inheriting from Joint.

Methods

Name	Description
arrange_child	Computes and sets the relative position of the child element.
child	Returns the child element of this wrapper, if any.
remove_child	Removes the child element from this wrapper.
set_child	Sets the child element wrapped by this wrapper.

Examples

Using an existing Wrapper class:

local widget = crystal.Widget:new();
widget:set_child(crystal.Image:new());

Implementing your own Wrapper class:

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

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

local MyWrapper = Class("MyWrapper", crystal.Wrapper);

MyWrapper.init = function(self)
  MyWrapper.super.init(self, MyWrapperJoint);
end

MyWrapper.arrange_child = function(self)
  -- Layout logic goes here
end