Layer Grouping

Layer ordering and grouping/ungrouping operations for the livery editor.

Overview

ui_liveryEditor_tools_group manages layer stack ordering (move up/down/top/bottom) and group creation/dissolution. It operates on the currently selected layer(s) via the selection API.

Extension path: lua/ge/extensions/ui/liveryEditor/tools/group.lua

Exports (M)

Internals

Order Bounds

• Top = siblingCount (highest order)
• Bottom = 2 (position 1 is typically the fill base layer)
• Moving up increments order; moving down decrements

Group Creation

M.groupLayers = function()
  -- Find shallowest selected layer to determine parent
  local shallowestLevel, parentUid = ...
  local newGroup = api.addLinkedSet({parentUid})

  -- Move each selected layer into the new group
  for k, layerUid in ipairs(selectedLayerUids) do
    api.moveLayer(uiLayer.order, uiLayer.parentUid, newOrder, newGroup.uid)
  end

  uiSelectionApi.select(newGroup.uid)
end

Ungroup Flow

1. Stores child UIDs (to avoid stale references during moves)
2. Moves each child from the group to the group's parent at sequential positions
3. Removes the now-empty group layer

How It Works

1. Order operations use api.moveLayer(from, fromParent, to, toParent) to reposition
2. Group creation uses api.addLinkedSet() then moves selected layers into it
3. Ungrouping iterates children, moves them out, then deletes the group shell
4. The selection automatically updates to the newly created group

Example Usage

local groupTool = extensions.ui_liveryEditor_tools_group

-- Move selected layer up
groupTool.moveOrderUp()

-- Group multiple selected layers
extensions.ui_liveryEditor_selection.select({uid1, uid2})
groupTool.groupLayers()

-- Ungroup
groupTool.ungroupLayer()

Additional Exports

The following exports are available but not yet documented in detail:

• M.changeOrder
• M.changeOrderToBottom
• M.changeOrderToTop
• M.moveOrderDown
• M.moveOrderDownById
• M.moveOrderUp
• M.moveOrderUpById
• M.setOrder
• M.ungroupLayer

See Also

• Livery Editor – Tools / Material - Related reference
• Livery Editor – Tools / Misc - Related reference
• Livery Editor – Tools / Settings - Related reference
• UI System Guide - Guide