Add script create_thumbnails.lua

Author: mfg92

contrib/create_thumbnails.lua

@@ -0,0 +1,86 @@
+--[[
+Create thumbnails plugin for darktable
+
+  darktable 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.
+  
+  darktable 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 darktable.  If not, see <http://www.gnu.org/licenses/>.
+]]
+
+--[[About this Plugin
+This plugin adds the button 'create thumbnails' to 'selected iamge[s]' module of darktable's lighttable view
+
+
+----USAGE----
+Click the 'create thumbnails' button to let the script create full sized previews of all selected images.
+
+To create previews of all images of a collection:
+Use CTRL+A to select all images of current collection and then press the button.
+]]
+
+local dt = require "darktable"
+local du = require "lib/dtutils"
+
+du.check_min_api_version("8.0.0", "create_thumbnails_button")
+
+-- stop running thumbnail creation
+local function stop_job(job)
+    job.valid = false
+end
+
+-- add button to 'selected images' module
+dt.gui.libs.image.register_action(
+    "create_thumbnails_button",
+    "create thumbnails",
+    function(event, images)
+        dt.print_log("creating thumbnails for " .. #images .. " images...")
+
+        -- create a new progress_bar displayed in darktable.gui.libs.backgroundjobs
+        job = dt.gui.create_job("creating thumbnails...", true, stop_job)
+
+        for i, image in pairs(images) do
+            -- generate all thumbnails, a max value of 8 means that also a full size preview image is created
+            image:generate_cache(true, 0, 8)
+            
+            -- update progress_bar
+            job.percent = i / #images
+
+            -- sleep for a short moment to give stop_job callback function a chance to run
+            dt.control.sleep(10)
+
+            -- stop early if darktable is shutdown or the cancle button of the progress bar is pressed
+            if dt.control.ending or not job.valid then
+                dt.print_log("creating thumbnails canceled!")
+                break
+            end
+        end
+
+        dt.print_log("create thumbnails done!")
+
+        -- stop job and remove progress_bar from ui, but only if not alreay canceled
+        if(job.valid) then
+            job.valid = false
+        end
+    end,
+    "create full sized previews of all selected images"
+)
+
+-- clean up function that is called when this module is getting disabled
+local function destroy()
+    dt.gui.libs.image.destroy_action("create_thumbnails_button")
+end
+
+
+local script_data = {}
+script_data.destroy = destroy -- 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
+return script_data