uiContainer.lua

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-- windower library imports
require('tables')

-- imports
local classes = require('classes')
local uiElement = require('uiElement')
local utils = require('utils')

-- create the class, derive from uiElement
local uiContainer = classes.class(uiElement)

-- constructor
-- @param layout optional: layout table defining this UI element. should contain an 'enabled' flag (bool) and a 'pos' (L{ x, y } from windower lists library)
-- @return true if the UI element is enabled
function uiContainer:init(layout)
    self.super:init(layout)

    self.children = T{}

    return self.isEnabled
end

-- disposes and removes all children
-- override this to free any resources created during init (also call super:dispose!)
function uiContainer:dispose()
    if not self.isEnabled then return end

    self:clearChildren(true)

    self.super:dispose()
end

-- adds a child UI element
-- @param child UI element derived from uiElement
-- @return the added child element
function uiContainer:addChild(child)
    if not self.isEnabled then return end

    if not child:instanceOf(uiElement) then
        utils:log('Failed to add UI child. Class must derive from uiElement!', 4)
        return nil
    end

    self.children:append(child)
    child.parent = self

    child:layoutElement()
    if self.isCreated then
        child:createPrimitives()
    end

    return child
end

-- removes a child UI element
-- @param child UI element that has been added using addChild() before
function uiContainer:removeChild(child)
    if not self.isEnabled then return end

    if not self.children:delete(child) then return end

    child.parent = nil
    child:layoutElement()
end

-- removes all child UI elements
-- @param dispose when true, children are also disposed
function uiContainer:clearChildren(dispose)
    if not self.isEnabled then return end

    for child in self.children:it() do
        child.parent = nil

        if dispose then
            child:dispose()
        else
            child:layoutElement()
        end
    end

    self.children:clear()
end

-- creates the windower primitives of all child UI elements in their z-order.
-- design convention: add all children that require z-ordering before calling this. 
-- adding children afterwards will always place primitives on top of existing ones regardless of configured z-order.
function uiContainer:createPrimitives()
    if not self.isEnabled then return end

    -- sort children by z-order ascending
    utils:insertionSort(self.children, function(a, b) return a.zOrder > b.zOrder end)

    for child in self.children:it() do
        child:createPrimitives()
    end

    self.super:createPrimitives()
end

-- calculates the element's and its children's absolute position and scale based on its parent
function uiContainer:layoutElement()
    if not self.isEnabled then return end

    self.super:layoutElement()

    for child in self.children:it() do
        child:layoutElement()
    end
end

function uiContainer:update()
    if not self.isEnabled then return end

    self.super:update()

    for child in self.children:it() do
        child:update()
    end
end

return uiContainer