official/apply_camera_style - backported bug fix to API-9.5.0 branch

official/selection_to_pdf

README.md

@@ -36,6 +36,7 @@ Name|Standalone|OS   |Purpose
 ----|:--------:|:---:|-------
 [AutoGrouper](https://docs.darktable.org/lua/stable/lua.scripts.manual/scripts/contrib/autogrouper)|Yes|LMW|Group images together by time
 [autostyle](https://docs.darktable.org/lua/stable/lua.scripts.manual/scripts/contrib/autostyle)|Yes|LMW|Automatically apply styles on import
+[auto_tag_modified](https://docs.darktable.org/lua/stable/lua.scripts.manual/scripts/contrib/auto_tag_modified)|Yes|LMW|Automatically tag images which have been manually modified in the darkroom
 change_group_leader|Yes|LMW|Change which image leads group
 [clear_GPS](https://docs.darktable.org/lua/stable/lua.scripts.manual/scripts/contrib/clear_gps)|Yes|LMW|Reset GPS information for selected images
 [CollectHelper](https://docs.darktable.org/lua/stable/lua.scripts.manual/scripts/contrib/collecthelper)|Yes|LMW|Add buttons to selected images module to manipulate the collection
@@ -178,7 +179,7 @@ If you don't have %LOCALAPPDATA%\darktable you have to start dartable at least o
 
 When darktable starts it looks for a file name `~/.config/darktable/luarc` (`%LOCALAPPDATA%\darktable\luarc` for windows) and reads it to see which scripts to include. The file is a plain text file with entries of the form `require "<directory>/<name>"` where directory is the directory containing the scripts, from the above list, and name is the name from the above list. To include GIMP the line would be `require "contrib/gimp"`.
 
-The recommended way to enable and disable specific scripts is using the script manager module.  To use script manager do the following:
+The recommended way to enable and disable specific scripts is using the [script manager](https://docs.darktable.org/lua/stable/lua.scripts.manual/scripts/tools/script_manager/) module.  To use script manager do the following:
 
 ### Linux or MacOS
 

contrib/RL_out_sharp.lua

@@ -106,7 +106,7 @@ local function preserve_metadata(original, sharpened)
   if exiftool then
     dtsys.external_command("exiftool -overwrite_original_in_place -tagsFromFile " .. original .. " " .. sharpened)
   else
-    dt.print_log(MODULE .. " exiftool not found,  metadata not preserved")
+    dt.print_log(MODULE_NAME .. " exiftool not found,  metadata not preserved")
   end
 end
 

contrib/auto_tag_modified.lua

@@ -0,0 +1,129 @@
+--[[
+
+    auto_tag_modified.lua - automatically tag an image when it has been manually modified in darkroom
+
+    Copyright (C) 2025 Michael Reiger <michael@rauschpfeife.net>, modeled after auto_snapshot.lua by Bill Ferguson <wpferguson@gamil.com>.
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+]]
+--[[
+    auto_tag_modified -
+
+    automatically tag an image when it has been manually modified in the darkroom, that is if its history has changed at the time it is closed from the darkroom.
+    (This will not catch applying styles from the light table though.)
+
+    ADDITIONAL SOFTWARE NEEDED FOR THIS SCRIPT
+    None
+
+    USAGE
+    * start the script from script_manager
+    * open an image in darkroom, and close it after making an operation that changes the history
+
+    BUGS, COMMENTS, SUGGESTIONS
+    Michael Reiger <michael@rauschpfeife.net>
+
+    CHANGES
+]]
+
+local dt = require "darktable"
+local du = require "lib/dtutils"
+local log = require "lib/dtutils.log"
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- C O N S T A N T S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+local MODULE <const> = "auto_tag_modified"
+local DEFAULT_TAG_NAME <const> = "darktable manually modified"
+local DEFAULT_LOG_LEVEL <const> = log.error
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- A P I  C H E C K
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+du.check_min_api_version("7.0.0", MODULE)   -- choose the minimum version that contains the features you need
+
+
+-- - - - - - - - - - - - - - - - - - - - - - - - - -
+-- I 1 8 N
+-- - - - - - - - - - - - - - - - - - - - - - - - - -
+
+local gettext = dt.gettext.gettext
+
+local function _(msgid)
+    return gettext(msgid)
+end
+
+
+-- - - - - - - - - - - - - - - - - - - - - - - - - -
+-- S C R I P T  M A N A G E R  I N T E G R A T I O N
+-- - - - - - - - - - - - - - - - - - - - - - - - - -
+
+local script_data = {}
+
+script_data.destroy = nil           -- function to destory the script
+script_data.destroy_method = nil    -- set to hide for libs since we can't destroy them commpletely yet
+script_data.restart = nil           -- how to restart the (lib) script after it's been hidden - i.e. make it visible again
+script_data.show = nil              -- only required for libs since the destroy_method only hides them
+
+script_data.metadata = {
+  name = _("auto tag modified"),            -- name of script
+  purpose = _("automatically tag an image when it has been manually modified in darkroom"),   -- purpose of script
+  author = "Michael Reiger <michael@rauschpfeife.net>",          -- your name and optionally e-mail address
+  help = "https://docs.darktable.org/lua/stable/lua.scripts.manual/scripts/contrib/auto_tag_modified/"                   -- URL to help/documentation
+}
+
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- L O G  L E V E L
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+log.log_level(DEFAULT_LOG_LEVEL)
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- N A M E  S P A C E
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+local auto_tag_modified = {}
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- P R E F E R E N C E S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+dt.preferences.register(MODULE, "auto_modified_tag_name", "string", "auto_tag_modified - " .. _("tag name to use for auto tagging modified images"),
+    _("tag name to use for auto tagging modified images"), DEFAULT_TAG_NAME)
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- D A R K T A B L E  I N T E G R A T I O N 
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+local function destroy()
+  dt.destroy_event(MODULE, "darkroom-image-history-changed")
+end
+
+script_data.destroy = destroy
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- E V E N T S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+dt.register_event(MODULE, "darkroom-image-history-changed",
+  function(event, image)
+    local tag_name = dt.preferences.read(MODULE, "auto_modified_tag_name", "string")
+    local tag = dt.tags.create(tag_name)
+    dt.tags.attach(tag, image)
+  end
+)
+
+return script_data

contrib/geoToolbox.lua

@@ -1,6 +1,7 @@
 --[[
     This file is part of darktable,
     copyright (c) 2016 Tobias Jakobs
+    copyright (c) 2025 Balázs Dura-Kovács
 
     darktable is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -63,21 +64,33 @@ gT.event_registered = false
 local labelDistance = dt.new_widget("label")
 labelDistance.label = _("distance:")
 
-local label_copy_gps_lat = dt.new_widget("check_button")
+local checkbox_copy_gps_lat = dt.new_widget("check_button")
 {
-  label = _("latitude: "),
   value = true
 }
-local label_copy_gps_lon = dt.new_widget("check_button")
+local entry_gps_lat = dt.new_widget("entry")
+{
+  tooltip = _("latitude (editable)"),
+  placeholder = _("latitude")
+}
+local checkbox_copy_gps_lon = dt.new_widget("check_button")
 {
-  label = _("longitude: "),
   value = true
 }
-local label_copy_gps_ele = dt.new_widget("check_button")
+local entry_gps_lon = dt.new_widget("entry")
+{
+  tooltip = _("longitude (editable)"),
+  placeholder = _("longitude")
+}
+local checkbox_copy_gps_ele = dt.new_widget("check_button")
 {
-  label = _("elevation: "),
   value = true
 }
+local entry_gps_ele = dt.new_widget("entry")
+{
+  tooltip = _("elevation (editable)"),
+  placeholder = _("elevation")
+}
 -- </GUI>
 
 local function select_with_gps()
@@ -294,20 +307,20 @@ local function copy_gps()
       copy_gps_have_data = false
     else
       copy_gps_have_data = true
-      if (image.latitude and label_copy_gps_lat.value) then
+      if (image.latitude and checkbox_copy_gps_lat.value) then
         copy_gps_latitude = image.latitude
       end
-      if (image.longitude and label_copy_gps_lon.value) then
+      if (image.longitude and checkbox_copy_gps_lon.value) then
           copy_gps_longitude = image.longitude
       end
-      if (image.elevation and label_copy_gps_ele.value) then
+      if (image.elevation and checkbox_copy_gps_ele.value) then
           copy_gps_elevation = image.elevation
       end
     end
 
-    label_copy_gps_lat.label = _("latitude: ") .. copy_gps_latitude
-    label_copy_gps_lon.label = _("longitude: ") .. copy_gps_longitude
-    label_copy_gps_ele.label = _("elevation: ") .. copy_gps_elevation
+    entry_gps_lat.text = copy_gps_latitude
+    entry_gps_lon.text = copy_gps_longitude
+    entry_gps_ele.text = copy_gps_elevation
 
     return
   end
@@ -317,14 +330,14 @@ local function paste_gps(image)
   local sel_images = dt.gui.action_images
 
   for jj,image in ipairs(sel_images) do
-    if (label_copy_gps_lat.value) then
-      image.latitude = copy_gps_latitude
+    if (checkbox_copy_gps_lat.value) then
+      image.latitude = entry_gps_lat.text
     end
-    if (label_copy_gps_lon.value) then
-      image.longitude = copy_gps_longitude
+    if (checkbox_copy_gps_lon.value) then
+      image.longitude = entry_gps_lon.text
     end
-    if (label_copy_gps_ele.value) then
-      image.elevation = copy_gps_elevation
+    if (checkbox_copy_gps_ele.value) then
+      image.elevation = entry_gps_ele.text
     end
   end
 end
@@ -663,13 +676,25 @@ gT.widget = dt.new_widget("box")
       tooltip = _("copy GPS data"),
       clicked_callback = copy_gps
     },
-    label_copy_gps_lat,
-    label_copy_gps_lon,
-    label_copy_gps_ele,
+    dt.new_widget("box"){
+      orientation = "horizontal",
+      checkbox_copy_gps_lat,
+      entry_gps_lat
+    },
+    dt.new_widget("box"){
+      orientation = "horizontal",
+      checkbox_copy_gps_lon,
+      entry_gps_lon
+    },
+    dt.new_widget("box"){
+      orientation = "horizontal",
+      checkbox_copy_gps_ele,
+      entry_gps_ele
+    },
     dt.new_widget("button")
     {
-      label = _("paste GPS data"),
-      tooltip = _("paste GPS data"),
+      label = _("apply GPS data to image"),
+      tooltip = _("apply GPS data to image"),
       clicked_callback = paste_gps
     },
     separator2,--------------------------------------------------------

lib/dtutils/string.lua

@@ -734,16 +734,33 @@ function dtutils_string.build_substitute_list(image, sequence, variable_string,
 
   local labels = get_colorlabels(image)
 
-  local eyear, emon, eday, ehour, emin, esec, emsec
+  local datetime_taken = ""
+  local use_millisecs = false
   if dt.preferences.read("darktable", "lighttable/ui/milliseconds", "bool") and is_api_9_1 then
+    use_millisecs = true
+  end
+
+  if image.exif_datetime_taken and image.exif_datetime_taken ~= "" then
+    datetime_taken = image.exif_datetime_taken
+  else
+    if use_millisecs then
+      datetime_taken = "0000:00:00 00:00:00.0"
+    else
+      datetime_taken = "0000:00:00 00:00:00"
+    end
+  end
+
+  local eyear, emon, eday, ehour, emin, esec, emsec
+  if use_millisecs then
     eyear, emon, eday, ehour, emin, esec, emsec = 
-      string.match(image.exif_datetime_taken, "(%d+):(%d+):(%d+) (%d+):(%d+):(%d+)%.(%d+)$")
+      string.match(datetime_taken, "(%d+):(%d+):(%d+) (%d+):(%d+):(%d+)%.(%d+)$")
   else
     emsec = "0"
     eyear, emon, eday, ehour, emin, esec = 
-      string.match(image.exif_datetime_taken, "(%d+):(%d+):(%d+) (%d+):(%d+):(%d+)$")
+      string.match(datetime_taken, "(%d+):(%d+):(%d+) (%d+):(%d+):(%d+)$")
   end
 
+
   local version_multi = #image:get_group_members() > 1 and image.duplicate_index or ""
 
   local replacements = {dtutils_string.get_basename(image.film.path),-- ROLL.NAME
@@ -753,7 +770,7 @@ function dtutils_string.build_substitute_list(image, sequence, variable_string,
                         image.id,                              -- ID
                         image.duplicate_index,                 -- VERSION
                         version_multi,                         -- VERSION.IF_MULTI
-                        image.version_name,                    -- VERSION.NAME
+                        image.version_name and image.version_name or "", -- VERSION.NAME
                         dt.configuration.version,              -- DARKTABLE.VERSION
                         "",                                    -- DARKTABLE.NAME
                         string.format("%04d", sequence),       -- SEQUENCE
@@ -781,8 +798,8 @@ function dtutils_string.build_substitute_list(image, sequence, variable_string,
                         eyear,                                 -- EXIF.YEAR
                         string.sub(eyear, 3),                  -- EXIF.YEAR.SHORT
                         emon,                                  -- EXIF.MONTH
-                        os.date("%B", exiftime2systime(image.exif_datetime_taken)), -- EXIF.MONTH.LONG
-                        os.date("%b", exiftime2systime(image.exif_datetime_taken)), -- EXIF.MONTH.SHORT
+                        os.date("%B", exiftime2systime(datetime_taken)), -- EXIF.MONTH.LONG
+                        os.date("%b", exiftime2systime(datetime_taken)), -- EXIF.MONTH.SHORT
                         eday,                                  -- EXIF.DAY
                         ehour,                                 -- EXIF.HOUR
                         "",                                    -- EXIF.HOUR.AMPM
@@ -819,11 +836,11 @@ function dtutils_string.build_substitute_list(image, sequence, variable_string,
                         "",                                    -- RATING.ICONS - wont be implemented
                         labels,                                -- LABELS
                         "",                                    -- LABELS.ICONS - wont be implemented
-                        image.title,                           -- TITLE
-                        image.description,                     -- DESCRIPTION
-                        image.creator,                         -- CREATOR
-                        image.publisher,                       -- PUBLISHER
-                        image.rights,                          -- RIGHTS
+                        image.title and image.title or "",     -- TITLE
+                        image.description and image.description or "", -- DESCRIPTION
+                        image.creator and image.creator or "",  -- CREATOR
+                        image.publisher and image.publisher or "", -- PUBLISHER
+                        image.rights and image.rights or "",   -- RIGHTS
                         "",                                    -- TAGS - wont be implemented
                         "",                                    -- SIDECAR.TXT - wont be implemented
                         pictures_folder,                       -- FOLDER.PICTURES
@@ -994,7 +1011,7 @@ local function treat(var_string)
     log.msg(log.info, "ret_val is " .. ret_val)
 
   elseif string.match(var_string, "SEQUENCE%[") then
-    local width, start = string.match(var_string, "(%d+),(%d)")
+    local width, start = string.match(var_string, "(%d+),(%d+)")
     local seq_val = tonumber(substitutes[var])
     local pat = "%0" .. width .. "d"
     substitutes[var_string] = string.format(pat, start + (seq_val - 1))

official/apply_camera_style.lua

@@ -34,12 +34,17 @@
     Bill Ferguson <wpferguson@gmail.com>
 
     CHANGES
+
+    20251202 - fixed pattern matching bugs affecting Canon EOS R? series
+               styles and styles being applied twice if images are reimported
+
+               Added more debugging statements to pattern matching functions
 ]]
 
 local dt = require "darktable"
 local du = require "lib/dtutils"
 -- local df = require "lib/dtutils.file"
--- local ds = require "lib/dtutils.string"
+local ds = require "lib/dtutils.string"
 -- local dtsys = require "lib/dtutils.system"
 local log = require "lib/dtutils.log"
 -- local debug = require "darktable.debug"
@@ -50,9 +55,11 @@ local log = require "lib/dtutils.log"
 -- - - - - - - - - - - - - - - - - - - - - - - - 
 
 local MODULE <const> = "apply_camera_style"
-local DEFAULT_LOG_LEVEL <const> = log.info
+local DEFAULT_LOG_LEVEL <const> = log.warn
 local TMP_DIR <const> = dt.configuration.tmp_dir
-local STYLE_PREFIX <const> = "_l10n_darktable camera styles|"
+local STYLE_PREFIX <const> = "_l10n_darktable|_l10n_camera styles|"
+local MAKER = 3
+local STYLE = 4
 
 -- path separator
 local PS <const> = dt.configuration.running_os == "windows" and "\\" or "/"
@@ -152,22 +159,32 @@ local function process_pattern(pattern)
 
   local log_level = set_log_level(acs.log_level)
 
+  log.msg(log.debug, "input pattern is " .. pattern)
+
   pattern = string.lower(pattern)
+  log.msg(log.debug, "lower case pattern is " .. pattern)
   -- strip off series
   pattern = string.gsub(pattern, " series$", "?")
+  log.msg(log.debug, "series stripped off pattern is " .. pattern)
   -- match a character
-  if string.match(pattern, "?$") then
+  if string.match(pattern, "r%?%?$") then
     -- handle EOS R case
-    pattern = string.gsub(pattern, "?", ".?")
+    pattern = string.gsub(pattern, "%?%?", ".?")
+    log.msg(log.debug, "matched EOS R pattern is " .. pattern)
   else
     pattern = string.gsub(pattern, "?", ".")
+    log.msg(log.debug, "didn't match EOS R pattern is " .. pattern)
   end
-  pattern = string.gsub(pattern, " ", " ?")
   -- escape dashes
   pattern = string.gsub(pattern, "%-", "%%-")
+  log.msg(log.debug, "escape dashes conditional pattern is " .. pattern)
+  -- make spaces optional
+  pattern = string.gsub(pattern, " ", " ?")
   -- until we end up with a set, I'll defer set processing, i.e. [...]
+  --log.msg(log.debug, "make spaces conditional again? pattern is " .. pattern)
   -- anchor the pattern to ensure we don't short match
   pattern = "^" .. pattern .. "$"
+  log.msg(log.debug, "anchored pattern is " .. pattern)
 
   restore_log_level(log_level)
 
@@ -223,25 +240,25 @@ local function get_camera_styles()
       log.msg(log.debug, "got " .. style.name)
 
       local parts = du.split(style.name, "|")
-      parts[2] = string.lower(parts[2])
-      log.msg(log.debug, "maker is " .. parts[2])
+      parts[MAKER] = string.lower(parts[MAKER])
+      log.msg(log.debug, "maker is " .. parts[MAKER])
 
-      if not acs.styles[parts[2]] then
-        acs.styles[parts[2]] = {}
-        acs.styles[parts[2]]["styles"] = {}
-        acs.styles[parts[2]]["patterns"] = {}
+      if not acs.styles[parts[MAKER]] then
+        acs.styles[parts[MAKER]] = {}
+        acs.styles[parts[MAKER]]["styles"] = {}
+        acs.styles[parts[MAKER]]["patterns"] = {}
       end
-      if parts[3] then
-        if not string.match(parts[3], "]") then
-          table.insert(acs.styles[parts[2]].styles, style)
+      if parts[STYLE] then
+        if not string.match(parts[STYLE], "]") then
+          table.insert(acs.styles[parts[MAKER]].styles, style)
           local processed_pattern = process_pattern(parts[#parts])
-          table.insert(acs.styles[parts[2]].patterns, processed_pattern)
+          table.insert(acs.styles[parts[MAKER]].patterns, processed_pattern)
           log.msg(log.debug, "pattern for " .. style.name .. " is " .. processed_pattern)
         else
-          local processed_patterns = process_set(parts[3])
+          local processed_patterns = process_set(parts[STYLE])
           for _, pat in ipairs(processed_patterns) do
-            table.insert(acs.styles[parts[2]].styles, style)
-            table.insert(acs.styles[parts[2]].patterns, pat)
+            table.insert(acs.styles[parts[MAKER]].styles, style)
+            table.insert(acs.styles[parts[MAKER]].patterns, pat)
             log.msg(log.debug, "pattern for " .. style.name .. " is " .. pat)
           end
         end
@@ -322,9 +339,11 @@ local function has_style_tag(image, tag_name)
   log.msg(log.debug, "looking for tag " .. tag_name)
 
   for _, tag in ipairs(image:get_tags()) do
-    log.msg(log.debug, "checking against " .. tag.name)
-    if tag.name == tag_name then
-      log.msg(log.debug, "matched tag " .. tag_name)
+    log.msg(log.debug, "got attached tag " .. tag.name)
+    local cleaned_tag_name = string.gsub(tag_name, "_l10n_", "")
+    log.msg(log.debug, "checking against " .. cleaned_tag_name)
+    if ds.sanitize_lua(tag.name) == cleaned_tag_name then
+      log.msg(log.debug, "matched tag " .. cleaned_tag_name)
       result = true
     end
   end
@@ -354,7 +373,7 @@ local function mangle_model(model)
     model = string.gsub(model, "eos 1200d", "eos rebel t5")
     model = string.gsub(model, "eos 1300d", "eos rebel t6")
     model = string.gsub(model, "eos 2000d", "eos rebel t7")
-    log.msg(log.debug, "mandle model returning " .. model)
+    log.msg(log.debug, "mangle model returning " .. model)
   end
 
   restore_log_level(log_level)
@@ -385,14 +404,15 @@ local function apply_style_to_images(images)
     if acs.styles[maker] then
       local no_match = true
       for i, pattern in ipairs(acs.styles[maker].patterns) do
+        log.msg(log.debug, "pattern is " .. pattern)
         if string.match(model, pattern) or 
            (i == #acs.styles[maker].patterns and string.match(pattern, "generic")) then
           local tag_name = "darktable|style|" .. acs.styles[maker].styles[i].name
           if not has_style_tag(image, tag_name) then
             image:apply_style(acs.styles[maker].styles[i])
-            no_match = false
             log.msg(log.info, "applied style " .. acs.styles[maker].styles[i].name .. " to " .. image.filename)
           end
+          no_match = false
           log.log_level(loglevel)
           break
         end

official/regenerate_thumbnails.lua

@@ -0,0 +1,267 @@
+--[[
+
+    regenerate_thumbnails.lua - regenerate mipmap cache for selected images
+
+    Copyright (C) 2025 Bill Ferguson <wpferguson@gmail.com>.
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+]]
+--[[
+    regenerate_thumbnails - regenerate mipmap cache for selected images
+
+    regenerate_thumbnails drops the cached thumbnail for each selected image
+    and generates a new thumbnail.
+
+    ADDITIONAL SOFTWARE NEEDED FOR THIS SCRIPT
+    None
+
+    USAGE
+    * enable the script in script_manager
+    * assign a shortcut, if desired, to apply the script by hovering
+      over a skull and using the shortcut to regenerate the thumbnail
+
+    BUGS, COMMENTS, SUGGESTIONS
+    Bill Ferguson <wpferguson@gmail.com>
+
+    CHANGES
+]]
+
+local dt = require "darktable"
+local du = require "lib/dtutils"
+-- local df = require "lib/dtutils.file"
+-- local ds = require "lib/dtutils.string"
+-- local dtsys = require "lib/dtutils.system"
+local log = require "lib/dtutils.log"
+-- local debug = require "darktable.debug"
+
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- A P I  C H E C K
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+du.check_min_api_version("7.0.0", MODULE)   -- choose the minimum version that contains the features you need
+
+
+-- - - - - - - - - - - - - - - - - - - - - - - - - -
+-- I 1 8 N
+-- - - - - - - - - - - - - - - - - - - - - - - - - -
+
+local gettext = dt.gettext.gettext
+
+local function _(msgid)
+    return gettext(msgid)
+end
+
+
+-- - - - - - - - - - - - - - - - - - - - - - - - - -
+-- S C R I P T  M A N A G E R  I N T E G R A T I O N
+-- - - - - - - - - - - - - - - - - - - - - - - - - -
+
+local script_data = {}
+
+script_data.destroy = nil           -- function to destory the script
+script_data.destroy_method = nil    -- set to hide for libs since we can't destroy them commpletely yet
+script_data.restart = nil           -- how to restart the (lib) script after it's been hidden - i.e. make it visible again
+script_data.show = nil              -- only required for libs since the destroy_method only hides them
+
+script_data.metadata = {
+  name = _("regenerate_thumbnails"),         -- visible name of script
+  purpose = _("regenerate mipmap cache for selected images"),   -- purpose of script
+  author = "Bill Ferguson <wpferguson@gmail.com>",   -- your name and optionally e-mail address
+  help = "https://docs.darktable.org/lua/development/lua.scripts.manual/scripts/official/regenerate_thumbnails"  -- URL to help/documentation
+}
+
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- C O N S T A N T S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+local MODULE <const> = "regenerate_thumbnails"
+local DEFAULT_LOG_LEVEL <const> = log.info
+local TMP_DIR <const> = dt.configuration.tmp_dir
+
+-- path separator
+local PS <const> = dt.configuration.running_os == "windows" and "\\" or "/"
+
+-- command separator
+local CS <const> = dt.configuration.running_os == "windows" and "&" or ";"
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- L O G  L E V E L
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+log.log_level(DEFAULT_LOG_LEVEL)
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- N A M E  S P A C E
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+local regenerate_thumbnails = {}
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- G L O B A L  V A R I A B L E S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- P R E F E R E N C E S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- A L I A S E S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+local namespace = regenerate_thumbnails
+local rt = regenerate_thumbnails
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- F U N C T I O N S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+-------------------
+-- helper functions
+-------------------
+
+local function set_log_level(level)
+  local old_log_level = log.log_level()
+  log.log_level(level)
+  return old_log_level
+end
+
+local function restore_log_level(level)
+  log.log_level(level)
+end
+
+local function pref_read(name, pref_type)
+  local old_log_level = set_log_level(sm.log_level)
+
+  log.msg(log.debug, "name is " .. name .. " and type is " .. pref_type)
+
+  local val = dt.preferences.read(MODULE, name, pref_type)
+
+  log.msg(log.debug, "read value " .. tostring(val))
+
+  restore_log_level(old_log_level)
+  return val
+end
+
+local function pref_write(name, pref_type, value)
+  local old_log_level = set_log_level(sm.log_level)
+
+  log.msg(log.debug, "writing value " .. tostring(value) .. " for name " .. name)
+
+  dt.preferences.write(MODULE, name, pref_type, value)
+
+  restore_log_level(old_log_level)
+end
+
+local function stop_job()
+  rt.job.valid = false
+end
+
+local function generate_thumbnails(images)
+  local has_job = false
+
+  if #images > 50 then
+    rt.job = dt.gui.create_job("regenerating thumbnails", true, stop_job)
+    has_job = true
+  end
+
+  for count, image in ipairs(images) do
+    image:drop_cache()
+    image:generate_cache(true, 1, 3)
+    if has_job then
+      if not rt.job.valid then
+        return
+      end
+      if count % 10 == 0 then
+        rt.job.percent = count / #images
+      end
+    end
+  end
+  if has_job then
+    rt.job.valid = false
+  end
+end
+
+local function update_button_sensitivity()
+  if #dt.gui.action_images > 0 then
+    dt.gui.libs.image.set_sensitive(MODULE, true)
+  else
+    dt.gui.libs.image.set_sensitive(MODULE, false)
+  end
+end
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- M A I N  P R O G R A M
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- U S E R  I N T E R F A C E
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+dt.gui.libs.image.register_action(
+  MODULE, 
+  _("generate thumbnails"),
+  function(event, images)
+    generate_thumbnails(images) 
+  end,
+  _("generate thumbnails")
+)
+
+update_button_sensitivity()
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- D A R K T A B L E  I N T E G R A T I O N 
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+local function destroy()
+  dt.destroy_event(MODULE, "selection-changed")
+  dt.destroy_event(MODULE, "mouse-over-image-changed")
+  dt.gui.libs.image.destroy_action(MODULE, "regenerate thumbnails")
+end
+
+script_data.destroy = destroy
+
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+-- E V E N T S
+-- - - - - - - - - - - - - - - - - - - - - - - - 
+
+dt.register_event(MODULE, "shortcut",
+  function(event, shortcut)
+    local images = dt.gui.action_images
+    if images then
+      generate_thumbnails(images)
+    end
+  end, "regenerate thumbnails"
+)
+
+dt.register_event(MODULE, "selection-changed",
+  function(event)
+    update_button_sensitivity()
+  end
+)
+
+dt.register_event(MODULE, "mouse-over-image-changed",
+  function(event, image)
+    if #dt.gui.selection() < 1 then
+      if image then
+        dt.gui.libs.image.set_sensitive(MODULE, true)
+      else
+        dt.gui.libs.image.set_sensitive(MODULE, false)
+      end
+    end
+  end
+)
+
+return script_data

official/selection_to_pdf.lua

@@ -44,6 +44,10 @@ local function _(msg)
   return gettext(msg)
 end
 
+local NIX_OPEN <const> = "xdg-open "
+local MAC_OPEN <const> = "open "
+local WIN_OPEN <const> = "start "
+
 -- return data structure for script_manager
 
 local script_data = {}
@@ -63,8 +67,8 @@ script_data.show = nil -- only required for libs since the destroy_method only h
 dt.preferences.register
    ("selection_to_pdf","Open with","string",
     _("a pdf viewer"),
-    _("can be an absolute pathname or the tool may be in the PATH"),
-    "xdg-open")
+    _("can be an absolute pathname or the tool may be in the PATH\nif not specified the system default will be used to open the pdf"),
+    "")
 
 local title_widget = dt.new_widget("entry") {
     placeholder = _("title")
@@ -115,8 +119,9 @@ local function thumbnail(latexfile,i,image,file)
   --  fact is that latex will get confused if the filename has multiple dots.
   --  so \includegraphics{file.01.jpg} wont work. We need to output the filename
   --  and extention separated, e.g: \includegraphics{{file.01}.jpg}
-  local filenoext=string.gsub(file, "(.*)(%..*)", "%1")
-  local ext=string.gsub(file, "(.*)(%..*)", "%2")
+
+  local filenoext = string.gsub(file, "(.*)(%..*)", "%1")
+  local ext = string.gsub(file, "(.*)(%..*)", "%2")
   my_write(latexfile,"\\begin{minipage}[b]{"..width.."\\textwidth}\n")
   my_write(latexfile,"\\includegraphics[width=\\textwidth]{{"..filenoext.."}"..ext.."}\\newline\n")
   my_write(latexfile,"\\centering{"..i..": \\verb|"..title.."|}\n")
@@ -138,7 +143,7 @@ dt.register_storage("export_pdf", _("export thumbnails to pdf"),
     end
     local thumbs_per_line = no_of_thumbs_widget.value
     thumbs_per_line = tonumber(thumbs_per_line)
-    width = (1/thumbs_per_line) - 0.01
+    width = (1 / thumbs_per_line) - 0.01
 
     local preamble = [[
     \documentclass[a4paper,10pt]{article}
@@ -148,31 +153,31 @@ dt.register_storage("export_pdf", _("export thumbnails to pdf"),
     \usepackage{geometry}
     \geometry{a4paper,left=5mm,right=5mm, top=5mm, bottom=5mm}
     \begin{document}
-    {\Large\bfseries ]]..my_title..[[} \\
+    {\Large\bfseries ]] .. my_title .. [[} \\
     \bigskip\bigskip
     ]]
 
     local errmsg
     local latexfile
-    latexfile,errmsg=io.open(filename,"w")
+    latexfile,errmsg = io.open(filename, "w")
     if not latexfile then
         error(errmsg)
       end
-      my_write(latexfile,preamble)
+      my_write(latexfile, preamble)
       local i = 1
-      for img,file in pairs(image_table) do
-         thumbnail(latexfile,i,img,file)
+      for img, file in pairs(image_table) do
+         thumbnail(latexfile, i, img, file)
          if i % thumbs_per_line == 0  then
-            my_write(latexfile,"\n\\bigskip\n")
+            my_write(latexfile, "\n\\bigskip\n")
          end
-         i = i+1
+         i = i + 1
       end
       my_write(latexfile,ending)
       latexfile:close()
 
       -- convert to PDF
-      local dir=string.gsub(filename, "(.*/)(.*)", "%1")
-      local locfile=string.gsub(filename, "(.*/)(.*)", "%2")
+      local dir = string.gsub(filename, "(.*/)(.*)", "%1")
+      local locfile = string.gsub(filename, "(.*/)(.*)", "%2")
       local command = "pdflatex -halt-on-error -output-directory "..dir.." "..locfile
       local result = dt.control.execute(command)
       if result ~= 0 then
@@ -181,9 +186,18 @@ dt.register_storage("export_pdf", _("export thumbnails to pdf"),
       end
 
       -- open the PDF
-      local pdffile=string.gsub(filename, ".tex", ".pdf")
+      local pdffile = string.gsub(filename, ".tex", ".pdf")
       command = dt.preferences.read("selection_to_pdf","Open with","string")
-      command = command.." "..pdffile
+      if command == "" then
+        if dt.configuration.running_os == "windows" then
+          command = WIN_OPEN
+        elseif dt.configuration.running_os == "macos" then
+          command = MAC_OPEN
+        else
+          command = NIX_OPEN
+        end
+      end
+      command = command .. " " .. pdffile
       local result = dt.control.execute(command)
       if result ~= 0 then
         dt.print(_("problem running pdf viewer")) -- this one is probably usefull to the user