word gap is set to smallest when selcting CJK languages

defaults.lua

@@ -34,17 +34,20 @@ DKOPTREADER_CONFIG_DETECT_INDENT = 1	-- 1 = enable, 0 = disable
 DKOPTREADER_CONFIG_DEFECT_SIZE = 1.0	-- range from 0.0 to 3.0
 DKOPTREADER_CONFIG_PAGE_MARGIN = 0.10	-- range from 0.0 to 1.0
 DKOPTREADER_CONFIG_LINE_SPACING = 1.2	-- range from 0.5 to 2.0
-DKOPTREADER_CONFIG_WORD_SAPCING = 0.15	-- range from 0.05 to 0.5
 DKOPTREADER_CONFIG_RENDER_QUALITY = 0.8	-- range from 0.5 to 1.0
 DKOPTREADER_CONFIG_AUTO_STRAIGHTEN = 0	-- range from 0 to 10
 DKOPTREADER_CONFIG_JUSTIFICATION = -1	-- -1 = auto, 0 = left, 1 = center, 2 = right, 3 = full
 DKOPTREADER_CONFIG_MAX_COLUMNS = 2		-- range from 1 to 4
 DKOPTREADER_CONFIG_CONTRAST = 1.0		-- range from 0.2 to 2.0
 
+-- word spacing for reflow
+DKOPTREADER_CONFIG_WORD_SAPCINGS = {0.05, 0.15, 0.375}  -- range from 0.05 to 0.5
+DKOPTREADER_CONFIG_DEFAULT_WORD_SAPCING = 0.15			-- range from 0.05 to 0.5
 -- document languages for OCR
 DKOPTREADER_CONFIG_DOC_LANGS_TEXT = {"English", "Chinese_S", "Chinese_T"}
-DKOPTREADER_CONFIG_DOC_LANGS_CODE = {"eng", "chi_sim", "chi_tra"}
-DKOPTREADER_CONFIG_DOC_DEFAULT_LANG_CODE = "eng"
+DKOPTREADER_CONFIG_DOC_LANGS_CODE = {"eng", "chi_sim", "chi_tra"}  -- ISO 639-3 language string, 
+DKOPTREADER_CONFIG_DOC_DEFAULT_LANG_CODE = "eng"  -- and make sure you have corresponding training data 
+
 
 -- ####################################################################
 -- following features are not supported right now

frontend/ui/data/koptoptions.lua

@@ -166,6 +166,8 @@ KoptOptions = {
 				toggle = DKOPTREADER_CONFIG_DOC_LANGS_TEXT,
 				values = DKOPTREADER_CONFIG_DOC_LANGS_CODE,
 				default_value = DKOPTREADER_CONFIG_DOC_DEFAULT_LANG_CODE,
+				event = "DocLangUpdate",
+				args = DKOPTREADER_CONFIG_DOC_LANGS_CODE,
 			},
 			{
 				name="screen_rotation",
@@ -178,8 +180,8 @@ KoptOptions = {
 				name = "word_spacing",
 				name_text = WORD_GAP_STR,
 				toggle = {SMALL_STR, MEDIUM_STR, LARGE_STR},
-				values = {0.05, 0.15, 0.375},
-				default_value = DKOPTREADER_CONFIG_WORD_SAPCING,
+				values = DKOPTREADER_CONFIG_WORD_SAPCINGS,
+				default_value = DKOPTREADER_CONFIG_DEFAULT_WORD_SAPCING,
 			},
 			{
 				name = "defect_size",

frontend/ui/reader/readerkopt.lua

@@ -49,3 +49,12 @@ function ReaderKoptListener:onZoomUpdate(zoom)
 	end
 end
 
+-- misc koptoption handler
+function ReaderKoptListener:onDocLangUpdate(lang)
+	if lang == "chi_sim" or lang == "chi_tra" or 
+		lang == "jpn" or lang == "kor" then
+		self.document.configurable.word_spacing = DKOPTREADER_CONFIG_WORD_SAPCINGS[1]
+	else
+		self.document.configurable.word_spacing = DKOPTREADER_CONFIG_WORD_SAPCINGS[3]
+	end
+end

frontend/ui/widget/config.lua

@@ -502,6 +502,7 @@ end
 function ConfigDialog:onConfigEvent(option_event, option_arg)
 	--DEBUG("config option event", option_event, option_arg)
 	self.ui:handleEvent(Event:new(option_event, option_arg))
+	self:onShowConfigPanel(self.panel_index)
 end
 
 function ConfigDialog:closeDialog()