Lua script for set color label on group images

colorlabel_group.lua

--[[

  Set color labels to group

  Script to provide shortcuts for setting color labels in images groups.
  Useful for those who are RAW+JPEG shooters.

  Installation and usage:

    1. Copy this file into ~/.config/darktable/lua/

    2. Add `require "colorlabel_group"` to new line in ~/.config/darktable/luarc

    3. Restart darktable

    4. Assign a keyboard shortcut to each action via daktable preferences > shortcuts > lua

       I use the following shortcuts:


       Set group red    - CRTL+F1
       Set group yellow - CRTL+F2
       Set group green  - CRTL+F3
       Set group blue   - CRTL+F4
       Set group purple - CRTL+F5


  Author:  Diego Cesar (diego.b.cesar@gmail.com), 
  License: GPLv2

  This script is based on based on Dom H (dom@hxy.io) work for rating group images

]]

local dt = require "darktable"

local function apply_label(color)
  local images = dt.gui.action_images
  for _, i in ipairs(images) do
      local members = i:get_group_members()
      for _, m in ipairs(members) do
          if color == "blue" then
		      m.blue = true
		  elseif color == "red" then
		      m.red = true
		  elseif color == "yellow" then
		      m.yellow = true
		  elseif color == "green" then
		      m.green = true
		  elseif color == "purple" then
		      m.purple = true
          end
      end
  end
  dt.print("applying color " ..color.. " to group(s)")
end

dt.register_event("shortcut",function(event, shortcut)
    apply_label("red")
end, "Set group red")

dt.register_event("shortcut",function(event, shortcut)
    apply_label("yellow")
end, "Set group yellow")

dt.register_event("shortcut",function(event, shortcut)
    apply_label("green")
end, "Set group green")

dt.register_event("shortcut",function(event, shortcut)
    apply_label("blue")
end, "Set group blue")

dt.register_event("shortcut",function(event, shortcut)
    apply_label("purple")
end, "Set group purple")