From d10cf968f19976f4b17f37e52e8f3c6285bad71e Mon Sep 17 00:00:00 2001
From: Bill Ferguson <wpferguson@gmail.com>
Date: Sun, 9 Aug 2020 01:33:09 -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/exportLUT.lua | 67 +++++++++++++++++++++++++++++++------------
 1 file changed, 48 insertions(+), 19 deletions(-)

diff --git a/contrib/exportLUT.lua b/contrib/exportLUT.lua
index aa76b0d..bd35fb3 100644
--- a/contrib/exportLUT.lua
+++ b/contrib/exportLUT.lua
@@ -41,6 +41,11 @@ end
 
 du.check_min_api_version("5.0.0", "exportLUT") 
 
+local eL = {}
+eL.module_installed = false
+eL.event_registered = false
+eL.widgets = {}
+
 -- Thanks Kevin Ertel for this bit
 local os_path_seperator = '/'
 if dt.configuration.running_os == 'windows' then os_path_seperator = '\\' end
@@ -119,27 +124,51 @@ local function export_luts()
   end
 end
 
+local function install_module()
+  if not eL.module_installed then
+    dt.register_lib(
+      _("export haldclut"),
+      _("export haldclut"),
+      true,
+      false,
+      {[dt.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 100}},
+      dt.new_widget("box")
+      {
+        orientation = "vertical",
+        table.unpack(eL.widgets),
+      },
+      nil,
+      nil
+    )
+    eL.module_installed = true
+  end
+end
+
 local export_button = dt.new_widget("button"){
   label = _("export"),
   clicked_callback = export_luts
 }
 
-dt.register_lib(
-  _("export haldclut"),
-  _("export haldclut"),
-  true,
-  false,
-  {[dt.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 100}},
-  dt.new_widget("box")
-  {
-    orientation = "vertical",
-    identity_label,
-    file_chooser_button,
-    output_label,
-    export_chooser_button,
-    warning_label,
-    export_button
-  },
-  nil,
-  nil
-)
+table.insert(eL.widgets, identity_label)
+table.insert(eL.widgets, file_chooser_button)
+table.insert(eL.widgets, output_label)
+table.insert(eL.widgets, export_chooser_button)
+table.insert(eL.widgets, warning_label)
+table.insert(eL.widgets, export_button)
+
+if dt.gui.current_view().name == "lighttable" then
+  install_module()
+else
+  if not eL.event_registered then
+    dt.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
+    )
+    eL.event_registered = true
+  end
+end
+