Panel:ChildrenSize
Description
Returns the width and height of the space between the position of the panel (upper-left corner) and the max bound of the children panels (farthest reaching lower-right corner).
Returns
Example
Creates a recursively generated box of panels where the size of each panel is determined by the parent panel's children size + 10x10 pixels.
Also they flash bluish colors, just for good measure.
-- Parent panel
BGPanel = vgui.Create("DPanel")
BGPanel:SetSize(200, 200)
BGPanel:Center()
local panel, child_size_w, child_size_h = nil, 0, 0
-- Create increasingly large blocks until children size exceeds the size of the panel
while(BGPanel:ChildrenSize() < BGPanel:GetSize()) do
child_w, child_h = BGPanel:ChildrenSize()
panel = vgui.Create("DPanel", BGPanel)
panel:SetPos(0, 0)
-- Increase size based on the children size
panel:SetSize(child_w+10, child_h+10)
-- Random bluish color every frame
function panel:PerformLayout()
self:InvalidateLayout() -- Call this again next frame
self:SetBackgroundColor(Color(math.random(0, 255), 255, math.random(0, 255)))
end
-- Move to back so we can see the effect
panel:MoveToBack()
end
Output: 
Garry's Mod
Rust
Steamworks
Wiki Help
S&box