diff --git a/djvureader.lua b/djvureader.lua
index f34c434f0..e929f765d 100644
--- a/djvureader.lua
+++ b/djvureader.lua
@@ -12,64 +12,8 @@ function DJVUReader:init()
 end
 
 -- open a DJVU file and its settings store
+-- DJVU does not support password yet
 function DJVUReader:open(filename)
 	self.doc = djvu.openDocument(filename)
-	if self.doc ~= nil then
-		self.settings = DocSettings:open(filename)
-		local gamma = self.settings:readsetting("gamma")
-		if gamma then
-			self.globalgamma = gamma
-		end
-		return true
-	end
-	return false
-end
-
---set viewer state according to zoom state
-function DJVUReader:setzoom(page)
-	local dc = self.newDC()
-	local pwidth, pheight = page:getSize(self.nulldc)
-
-	if self.globalzoommode == self.ZOOM_FIT_TO_PAGE then
-		self.globalzoom = width / pwidth
-		self.offset_x = 0
-		self.offset_y = (height - (self.globalzoom * pheight)) / 2
-		if height / pheight < self.globalzoom then
-			self.globalzoom = height / pheight
-			print(width, (self.globalzoom * pwidth))
-			self.offset_x = (width - (self.globalzoom * pwidth)) / 2
-			self.offset_y = 0
-		end
-	elseif self.globalzoommode == self.ZOOM_FIT_TO_PAGE_WIDTH then
-		self.globalzoom = width / pwidth
-		self.offset_x = 0
-		self.offset_y = (height - (self.globalzoom * pheight)) / 2
-	elseif self.globalzoommode == self.ZOOM_FIT_TO_PAGE_HEIGHT then
-		self.globalzoom = height / pheight
-		self.offset_x = (width - (self.globalzoom * pwidth)) / 2
-		self.offset_y = 0
-	end
-
-	dc:setZoom(self.globalzoom)
-	-- record globalzoom for manual zoom in/out
-	self.globalzoom_orig = self.globalzoom
-
-	dc:setRotate(self.globalrotate);
-	dc:setOffset(self.offset_x, self.offset_y)
-	self.fullwidth, self.fullheight = page:getSize(dc)
-	self.min_offset_x = fb.bb:getWidth() - self.fullwidth
-	self.min_offset_y = fb.bb:getHeight() - self.fullheight
-	if(self.min_offset_x > 0) then
-		self.min_offset_x = 0
-	end
-	if(self.min_offset_y > 0) then
-		self.min_offset_y = 0
-	end
-
-	-- set gamma here, we don't have any other good place for this right now:
-	if self.globalgamma ~= self.GAMMA_NO_GAMMA then
-		print("gamma correction: "..self.globalgamma)
-		dc:setGamma(self.globalgamma)
-	end
-	return dc
+	return self:loadSettings(filename)
 end
diff --git a/pdfreader.lua b/pdfreader.lua
index 8973cfadf..5bd12aa73 100644
--- a/pdfreader.lua
+++ b/pdfreader.lua
@@ -14,13 +14,5 @@ end
 -- open a PDF file and its settings store
 function PDFReader:open(filename, password)
 	self.doc = pdf.openDocument(filename, password or "")
-	if self.doc ~= nil then
-		self.settings = DocSettings:open(filename)
-		local gamma = self.settings:readsetting("gamma")
-		if gamma then
-			self.globalgamma = gamma
-		end
-		return true
-	end
-	return false
+	return self:loadSettings(filename)
 end
diff --git a/unireader.lua b/unireader.lua
index 3d476c2ae..812732785 100644
--- a/unireader.lua
+++ b/unireader.lua
@@ -72,10 +72,41 @@ function UniReader:new(o)
 	return o
 end
 
+--[[ 
+	For a new specific reader,
+	you must always overwrite following two methods:
+
+	* self:init()
+	* self:open()
+
+	overwrite other methods if needed.
+--]]
 function UniReader:init()
 	print("empty initialization method!")
 end
 
+-- open a file and its settings store
+-- tips: you can use self:loadSettings in open() method.
+function UniReader:open(filename, password)
+	return false
+end
+
+
+
+--[ following are default methods ]--
+
+function UniReader:loadSettings(filename)
+	if self.doc ~= nil then
+		self.settings = DocSettings:open(filename)
+		local gamma = self.settings:readsetting("gamma")
+		if gamma then
+			self.globalgamma = gamma
+		end
+		return true
+	end
+	return false
+end
+
 -- guarantee that we have enough memory in cache
 function UniReader:cacheclaim(size)
 	if(size > self.cache_max_memsize) then
@@ -136,11 +167,6 @@ function UniReader:clearcache()
 	self.cache_current_memsize = 0
 end
 
--- open a file and its settings store
-function UniReader:open(filename, password)
-	return false
-end
-
 -- set viewer state according to zoom state
 function UniReader:setzoom(page)
 	local dc = self.newDC()