Merge pull request #4 from marco44/master

Add an autostyle lua script, which autoapplies a style on a tag found by...

contrib/autostyle.lua

@@ -0,0 +1,144 @@
+--[[
+Autostyle
+Automatically apply a given style when an exif tag is present in the file. This tagged is checked with exiftool, in order to be able to match very exotic tags.
+I wrote this initially to be able to apply a style to compensate for Auto-DR from my Fujifilm camera
+
+AUTHOR
+Marc Cousin (cousinmarc@gmail.com)
+
+INSTALATION
+* copy this file in $CONFIGDIR/lua/ where CONFIGDIR
+is your darktable configuration directory
+* add the following line in the file $CONFIGDIR/luarc
+  require "autostyle"
+
+USAGE
+* set the exif configuration string in your lua configuration
+  mine, for instance, is AutoDynamicRange=200%=>DR200"
+  meaning that I automatically want to apply my DR200 style on all
+  images where exiftool returns '200%' for the AutoDynamicRange tag
+* if you want to be able to apply it manually to already imported
+  images, define a shortcut (lua shortcuts). As I couldn't find an event for
+  when a development is removed, so the autostyle won't be applied again, 
+  this shortcut is also helpful then
+* import your images, or use the shortcut on your already imported images
+* To determine which tag you want, list all tags with exiftool:
+  exiftool -j XE021351.RAF, and find the one you want to use
+  you can check it with 
+  > exiftool -AutoDynamicRange XE021351.RAF
+  Auto Dynamic Range              : 200%
+
+
+LICENSE
+GPLv2
+
+]]
+
+local darktable = require "darktable"
+
+
+-- Forward declare the functions
+local autostyle_apply_one_image,autostyle_apply_one_image_event,autostyle_apply,exiftool_attribute,capture
+
+-- Tested it with darktable 1.6.1 and darktable git from 2014-01-25
+darktable.configuration.check_version(...,{2,0,2},{2,1,0})
+
+-- Receive the event triggered
+function autostyle_apply_one_image_event(event,image)
+  autostyle_apply_one_image(image)
+end
+
+-- Apply the style to an image, if it matches the tag condition
+function autostyle_apply_one_image (image)
+  -- We need the tag, the value and the style_name provided from the configuration string
+  local tag,value,style_name=string.match(darktable.preferences.read("autostyle","exif_tag","string"),"(%g+)%s*=%s*(%g+)%s*=>%s*(%g+)")
+
+  -- check they all exist (correct syntax)
+  if (not tag) then
+	  darktable.print("EXIF TAG not found in " .. darktable.preferences.read("autostyle","exif_tag","string"))
+	  return
+  end
+  if (not value) then
+	  darktable.print("value to match not found in " .. darktable.preferences.read("autostyle","exif_tag","string"))
+	  return
+  end
+  if (not style_name) then
+	  darktable.print("style name not found in " .. darktable.preferences.read("autostyle","exif_tag","string"))
+	  return
+  end
+
+  -- First find the style (we have its name)
+  local styles= darktable.styles
+  local style
+  for _,s in ipairs(styles) do
+	  if s.name == style_name then
+		  style=s
+	  end
+  end
+  if (not style) then
+	  darktable.print("style not found for autostyle: " .. style_name)
+  end
+
+  -- Apply the style to image, if it is tagged
+  local ok,auto_dr_attr= pcall(exiftool_attribute,image.path .. '/' .. image.filename,tag)
+  -- If the lookup fails, stop here
+  if (not ok) then
+    return
+  end
+  if auto_dr_attr==value then
+--	  darktable.print("Image " .. image.filename .. ": autostyle automatically applied " .. darktable.preferences.read("autostyle","exif_tag","string") )
+	  darktable.styles.apply(style,image)
+--  else
+--	  darktable.print("Image " .. image.filename .. ": autostyle not applied, exif tag " .. darktable.preferences.read("autostyle","exif_tag","string")  .. " not matched: " .. auto_dr_attr)
+  end
+end 
+
+
+function autostyle_apply( shortcut)
+  local images = darktable.gui.action_images
+  for _,image in pairs(images) do
+    autostyle_apply_one_image(image)
+  end
+end
+
+-- Retrieve the attribute through exiftool
+function exiftool_attribute(path,attr)
+  local cmd="exiftool -" .. attr .. " '" ..path.. "'";
+  local exifresult=get_stdout(cmd)
+  local attribute=string.match(exifresult,": (.*)")
+  if (attribute == nil) then
+    darktable.print( "Could not find the attribute " .. attr .. " using the command: <" .. cmd .. ">")
+    -- Raise an error to the caller
+    error( "Could not find the attribute " .. attr .. " using the command: <" .. cmd .. ">");
+  end
+  return attribute
+end
+
+-- run command and retrieve stdout
+function get_stdout(cmd)
+  -- Open the command, for reading
+  local fd = assert(io.popen(cmd, 'r'))
+  -- yield to other lua threads until data is ready to be read
+  coroutine.yield("FILE_READABLE",fd)
+  -- slurp the whole file
+  local data = assert(fd:read('*a'))
+
+  fd:close()
+  -- Replace carriage returns and linefeeds with spaces
+  data = string.gsub(data, '[\n\r]+', ' ')
+  -- Remove spaces at the beginning
+  data = string.gsub(data, '^%s+', '')
+  -- Remove spaces at the end
+  data = string.gsub(data, '%s+$', '')
+  return data
+end
+
+-- Registering events
+darktable.register_event("shortcut",autostyle_apply,
+       "Apply your chosen style from exiftool tags")
+
+darktable.preferences.register("autostyle","exif_tag","string","Autostyle: EXIF_tag=value=>style","apply a style automatically if an EXIF_tag matches value. Find the tag with exiftool","")
+
+darktable.register_event("post-import-image",autostyle_apply_one_image_event)
+
+