From dfb8d4e7c6b7f2219f2a8c1068d167e86c0dbb2e Mon Sep 17 00:00:00 2001
From: Bill Ferguson <wpferguson@gmail.com>
Date: Sun, 9 Aug 2020 01:48:36 -0400
Subject: [PATCH] Added check to ensure we are in lighttable view prior to
 callling darktable.register_lib.  If darktable was invoked in single image
 (darkroom) mode, then an event handler is registered to detect the change
 from darkroom mode to lighttable mode so that we can then call
 darktable.register_lib.

---
 contrib/LabelsToTags.lua | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/contrib/LabelsToTags.lua b/contrib/LabelsToTags.lua
index 044e920..29f9322 100644
--- a/contrib/LabelsToTags.lua
+++ b/contrib/LabelsToTags.lua
@@ -55,6 +55,10 @@ du.check_min_api_version("3.0.0", "LabelsToTags")
 -- Lua 5.3 no longer has "unpack" but "table.unpack"
 unpack = unpack or table.unpack
 
+local ltt = {}
+ltt.module_installed = false
+ltt.event_registered = false
+
 local LIB_ID = "LabelsToTags"
 
 -- Helper functions: BEGIN
@@ -184,7 +188,7 @@ local function doTagging(selfC)
    job.valid = false
 end
 
-local my_widget = darktable.new_widget("box") {
+ltt.my_widget = darktable.new_widget("box") {
    orientation = "vertical",
    mappingComboBox,
    darktable.new_widget("button") {
@@ -217,6 +221,15 @@ darktable.register_tag_mapping = function(name, mapping)
    mappingComboBox.reset_callback(mappingComboBox)
 end
 
+local function install_module()
+  if not ltt.module_installed then
+   darktable.register_lib(LIB_ID,"labels to tags",true,true,{
+              [darktable.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER",20},
+                            },ltt.my_widget,nil,nil)
+    ltt.module_installed = true
+  end
+end
+
 --[[
 darktable.register_tag_mapping("Example",
 			       { ["+----*"] = { "Red", "Only red" },
@@ -229,6 +242,19 @@ darktable.register_tag_mapping("Example",
 				 ["*****R"] = { "Rejected" } })
 ]]
 
-darktable.register_lib(LIB_ID,"labels to tags",true,true,{
-			  [darktable.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER",20},
-								 },my_widget,nil,nil)
+if darktable.gui.current_view().name == "lighttable" then
+  install_module()
+else
+  if not ltt.event_registered then
+    darktable.register_event(
+      "view-changed",
+      function(event, old_view, new_view)
+        if new_view.name == "lighttable" and old_view.name == "darkroom" then
+          install_module()
+         end
+      end
+    )
+    ltt.event_registered = true
+  end
+end
+