diff --git a/src/Graphics/X11/Turtle.hs b/src/Graphics/X11/Turtle.hs
--- a/src/Graphics/X11/Turtle.hs
+++ b/src/Graphics/X11/Turtle.hs
@@ -1,3 +1,6 @@
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE TypeSynonymInstances #-}
+
 module Graphics.X11.Turtle (
 	Field,
 	Turtle,
@@ -31,7 +34,9 @@
 	isdown,
 
 	bgcolor,
+	rgbToColor,
 	pencolor,
+	Color(..),
 	pensize,
 
 	clear,
@@ -59,7 +64,8 @@
 
 	getInputs,
 	sendInputs,
-	getSVG
+	getSVG,
+	ColorClass
 ) where
 
 import Graphics.X11.TurtleMove(
@@ -67,13 +73,12 @@
 	forkIOX, openField, closeField,
 	addCharacter, addLayer, fieldSize, clearLayer, clearCharacter,
 	addThread, fieldColor, onclick, onrelease, ondrag, onkeypress, waitField,
-	Color'(..),
 	moveTurtle
  )
 import Graphics.X11.TurtleInput(
 	TurtleInput(..), TurtleState,
 	getTurtleStates, getPosition, getPendown, undonum, visible, direction,
-	SVG, drawed
+	SVG, drawed, Color(..)
  )
 import qualified Graphics.X11.TurtleInput as S(degrees)
 import Graphics.X11.TurtleShape(lookupShape)
@@ -81,11 +86,10 @@
 import Control.Monad(replicateM_, zipWithM_)
 import Prelude hiding(Left)
 import Data.IORef(IORef, newIORef, readIORef, modifyIORef)
-import Data.Bits(shift, (.|.))
 import Data.Fixed(mod')
 
 xturtleVersion :: (Int, String)
-xturtleVersion = (25, "0.0.14")
+xturtleVersion = (29, "0.0.15")
 
 data Turtle = Turtle {
 	field :: Field,
@@ -183,15 +187,24 @@
 penup = flip sendCommand Penup
 pendown = flip sendCommand Pendown
 
-pencolor :: Turtle -> Double -> Double -> Double -> IO ()
-pencolor t r_ g_ b_ = sendCommand t $ Pencolor r_ g_ b_ -- c
+rgbToColor :: Double -> Double -> Double -> Color
+rgbToColor r g b = RGB (round $ r * 0xff) (round $ g * 0xff) (round $ b * 0xff)
 
-bgcolor :: Field -> Double -> Double -> Double -> IO ()
-bgcolor f r_ g_ b_ = fieldColor f $ Color c
-	where
-	c = shift r 16 .|. shift g 8 .|. b
-	[r, g, b] = map (round . (* 255)) [r_, g_, b_]
+pencolor :: ColorClass c => Turtle -> c -> IO ()
+pencolor t c = sendCommand t $ Pencolor $ getColor c
 
+class ColorClass a where
+	getColor :: a -> Color
+
+instance ColorClass String where
+	getColor = ColorName
+
+instance (Integral r, Integral g, Integral b) => ColorClass (r, g, b) where
+	getColor (r, g, b) = RGB (fromIntegral r) (fromIntegral g) (fromIntegral b)
+
+bgcolor :: ColorClass c => Field -> c -> IO ()
+bgcolor f = fieldColor f . getColor
+
 pensize :: Turtle -> Double -> IO ()
 pensize t = sendCommand t . Pensize
 
@@ -253,5 +266,4 @@
 sendInputs t = mapM_ (sendCommand t)
 
 getSVG :: Turtle -> IO [SVG]
-getSVG t = do
-	fmap (reverse . drawed . (states t !!)) $ readIORef $ stateIndex t
+getSVG t = fmap (reverse . drawed . (states t !!)) $ readIORef $ stateIndex t
diff --git a/src/Graphics/X11/TurtleField.hs b/src/Graphics/X11/TurtleField.hs
--- a/src/Graphics/X11/TurtleField.hs
+++ b/src/Graphics/X11/TurtleField.hs
@@ -29,9 +29,7 @@
 	onkeypress,
 
 	forkIOX,
-	addThread,
-
-	Color'(..)
+	addThread
 ) where
 
 import Graphics.X11(
@@ -55,16 +53,17 @@
 	defaultVisual, defaultColormap, defaultScreenOfDisplay,
 
 	supportsLocale, setLocaleModifiers,
-	xK_VoidSymbol, buttonPress, buttonRelease
+	xK_VoidSymbol, buttonPress, buttonRelease,
+	allocNamedColor
  )
-import qualified Graphics.X11 as X (drawLine)
+import qualified Graphics.X11 as X (drawLine, Color(..))
 import Graphics.X11.Xlib.Extras(Event(..), getEvent)
 import Graphics.X11.Xft
 import Graphics.X11.Xrender
 import Graphics.X11.Xim
 
 import Data.IORef(IORef, newIORef, readIORef, writeIORef, modifyIORef)
-import Data.Bits((.|.))
+import Data.Bits((.|.), shift)
 import Data.Convertible(convert)
 import Data.List.Tools(modifyAt, setAt)
 import Data.Bool.Tools(whether)
@@ -81,10 +80,7 @@
 import System.Locale.SetLocale
 import Foreign.C.Types
 
-data Color' = Color {pixel :: Pixel}
-
-colorToPixel :: Color' -> Pixel
-colorToPixel = pixel
+import Text.XML.YJSVG(Color(..))
 
 data Field = Field{
 	fDisplay :: Display,
@@ -125,7 +121,7 @@
 
 openField :: IO Field
 openField = do
-	setLocale LC_CTYPE Nothing >>= maybe (error "Can't set locale.") return
+	_ <- setLocale LC_CTYPE Nothing >>= maybe (error "Can't set locale.") return
 	_ <- initThreads
 	unlessM supportsLocale $ error "Current locale is notSupported."
 	_ <- setLocaleModifiers ""
@@ -247,7 +243,8 @@
 			Nothing -> killThread th1 >> return False
 			_ -> return True
 
--- onclick, onrelease :: Field -> (Double -> Double -> IO Bool) -> IO ()
+onclick :: Field -> (Int -> Double -> Double -> IO Bool) -> IO ()
+onrelease :: Field -> (Double -> Double -> IO Bool) -> IO ()
 onclick f = writeIORef $ fOnclick f
 onrelease f = writeIORef $ fOnrelease f
 
@@ -257,15 +254,24 @@
 onkeypress :: Field -> (Char -> IO Bool) -> IO ()
 onkeypress f = writeIORef $ fKeypress f
 
-fieldColor :: Field -> Color' -> IO ()
-fieldColor f clr = do
-	setForeground (fDisplay f) (fGCBG f) $ colorToPixel clr
+fieldColor :: Field -> Color -> IO ()
+fieldColor f@Field{fDisplay = dpy} c = do
+	clr <- getColorPixel dpy c
+	setForeground (fDisplay f) (fGCBG f) clr
 	let bufs = [fUndoBuf f, fBG f, fBuf f]
 	width <- readIORef $ fWidth f
 	height <- readIORef $ fHeight f
 	forM_ bufs $ \bf -> fillRectangle (fDisplay f) bf (fGCBG f) 0 0 width height
 	redrawAll f
 
+getColorPixel :: Display -> Color -> IO Pixel
+getColorPixel _ (RGB r g b) = return $ shift (fromIntegral r) 16 .|.
+	shift (fromIntegral g) 8 .|. fromIntegral b
+getColorPixel dpy (ColorName cn) = do
+	let	scr = defaultScreen dpy
+		colormap = defaultColormap dpy scr
+	fmap (X.color_pixel . fst) $ allocNamedColor dpy colormap cn
+
 getConnection :: Field -> Fd
 getConnection = Fd . connectionNumber . fDisplay
 
@@ -311,7 +317,7 @@
 	unless cl $ act >> return ()
 
 drawLineNotFlush ::
-	Layer -> Double -> Color' -> Double -> Double -> Double -> Double -> IO ()
+	Layer -> Double -> Color -> Double -> Double -> Double -> Double -> IO ()
 drawLineNotFlush l@Layer{layerField = f} lw_ clr x1 y1 x2 y2 = runIfOpened f $ do
 	drawLineBuf f lw clr fBG x1 y1 x2 y2
 	addLayerAction l $ whether
@@ -320,7 +326,7 @@
 	where
 	lw = round lw_
 
-drawLine :: Layer -> Double -> Color' -> Double -> Double -> Double -> Double -> IO ()
+drawLine :: Layer -> Double -> Color -> Double -> Double -> Double -> Double -> IO ()
 drawLine l@Layer{layerField = f} lw_ clr x1 y1 x2 y2 = runIfOpened f $ do
 	drawLineBuf f lw clr fBG x1 y1 x2 y2 >> redrawCharacters f
 	addLayerAction l $ whether
@@ -363,18 +369,20 @@
 clearCharacter c = runIfOpened (characterField c) $
 	setCharacter c $ return ()
 
-drawCharacter :: Character -> Color' -> [(Double, Double)] -> IO ()
-drawCharacter c@Character{characterField = f} clr sh =
+drawCharacter :: Character -> Color -> [(Double, Double)] -> IO ()
+drawCharacter c@Character{characterField = f} cl sh =
 	runIfOpened (characterField c) $ setCharacter c $ do
-		setForeground (fDisplay f) (fGC f) $ colorToPixel clr
+		clr <- getColorPixel (fDisplay f) cl
+		setForeground (fDisplay f) (fGC f) clr
 		fillPolygonBuf (characterField c) sh
 
-drawCharacterAndLine ::	Character -> Color' -> [(Double, Double)] -> Double ->
+drawCharacterAndLine ::	Character -> Color -> [(Double, Double)] -> Double ->
 	Double -> Double -> Double -> Double -> IO ()
-drawCharacterAndLine c@Character{characterField = f} clr ps lw_ x1 y1 x2 y2 =
+drawCharacterAndLine c@Character{characterField = f} cl ps lw_ x1 y1 x2 y2 =
 	runIfOpened f $ setCharacter c $ do
-		setForeground (fDisplay f) (fGC f) $ colorToPixel clr
-		fillPolygonBuf f ps >> drawLineBuf f lw clr fBuf x1 y1 x2 y2
+		clr <- getColorPixel (fDisplay f) cl
+		setForeground (fDisplay f) (fGC f) clr
+		fillPolygonBuf f ps >> drawLineBuf f lw cl fBuf x1 y1 x2 y2
 	where
 	lw = round lw_
 
@@ -428,10 +436,11 @@
 	fillPolygon (fDisplay f) (fBuf f) (fGC f) (map (uncurry Point) ps)
 		nonconvex coordModeOrigin
 
-drawLineBuf :: Field -> Int -> Color' -> (Field -> Pixmap) ->
+drawLineBuf :: Field -> Int -> Color -> (Field -> Pixmap) ->
 	Double -> Double -> Double -> Double -> IO ()
-drawLineBuf f@Field{fDisplay = dpy, fGC = gc} lw clr bf x1_ y1_ x2_ y2_ = do
-	setForeground (fDisplay f) (fGC f) $ colorToPixel clr
+drawLineBuf f@Field{fDisplay = dpy, fGC = gc} lw c bf x1_ y1_ x2_ y2_ = do
+	clr <- getColorPixel dpy c
+	setForeground (fDisplay f) (fGC f) clr
 	setLineAttributes (fDisplay f) (fGC f) (fromIntegral lw) lineSolid capRound joinRound
 	[(x1, y1), (x2, y2)] <- convertPos f [(x1_, y1_), (x2_, y2_)]
 	X.drawLine dpy (bf f) gc x1 y1 x2 y2
diff --git a/src/Graphics/X11/TurtleInput.hs b/src/Graphics/X11/TurtleInput.hs
--- a/src/Graphics/X11/TurtleInput.hs
+++ b/src/Graphics/X11/TurtleInput.hs
@@ -11,12 +11,12 @@
 	degrees,
 	drawed,
 
-	SVG
+	SVG,
+	Color(..)
 ) where
 
 import Graphics.X11.TurtleState(TurtleState(..), initialTurtleState,
-	pencolor',
-	SVG(..), Position(..))
+	SVG(..), Position(..), Color(..))
 import Control.Concurrent.Chan(Chan, newChan, getChanContents)
 import Prelude hiding(Left)
 
@@ -39,7 +39,7 @@
 	| Forward Double
 	| Left Double
 	| Undonum Int
-	| Pencolor Double Double Double
+	| Pencolor Color
 	| Pensize Double
 	| Degrees Double
 	| Write String Double String
@@ -57,9 +57,8 @@
 nextTurtle t (ShapeSize ss) = (clearState t){shapesize = ss}
 nextTurtle t (Goto x y) = (clearState t){position = (x, y), line = pendown t,
 	drawed = if pendown t then ln : drawed t else drawed t}
---		then Line (pencolor t) (pensize t) (position t) (x, y) : drawed t else drawed t} 
 	where
-	ln = Line (uncurry Center $ position t) (Center x y) (pencolor' t)
+	ln = Line (uncurry Center $ position t) (Center x y) (pencolor t)
 		(pensize t)
 nextTurtle t (Rotate d) = (clearState t){direction = d}
 nextTurtle t Pendown = (clearState t){pendown = True}
@@ -67,7 +66,7 @@
 nextTurtle t (SetVisible v) = (clearState t){visible = v}
 nextTurtle t (Undonum un) = (clearState t){undonum = un}
 nextTurtle t (Clear) = (clearState t){clear = True, drawed = []}
-nextTurtle t (Pencolor r g b) = (clearState t){red = r, green = g, blue = b}-- setPencolor (clearState t) c
+nextTurtle t (Pencolor c) = (clearState t){pencolor = c}
 nextTurtle t (Pensize ps) = (clearState t){pensize = ps}
 nextTurtle t (Degrees ds) = (clearState t){
 	degrees = ds,
@@ -78,8 +77,7 @@
  }
 	where
 	(x, y) = position t
-	d = Text (Center x y) sz (pencolor' t) fnt str
---	d = Str (red t, green t, blue t) fnt sz (position t) str
+	d = Text (Center x y) sz (pencolor t) fnt str
 nextTurtle _ _ = error "not defined"
 
 clearState :: TurtleState -> TurtleState
diff --git a/src/Graphics/X11/TurtleMove.hs b/src/Graphics/X11/TurtleMove.hs
--- a/src/Graphics/X11/TurtleMove.hs
+++ b/src/Graphics/X11/TurtleMove.hs
@@ -19,13 +19,13 @@
 	onkeypress,
 	waitField,
 	writeString,
-	Color'(..),
+--	Color'(..),
 
 	moveTurtle
 ) where
 
-import Graphics.X11.TurtleState(TurtleState(..), pencolor, SVG(..), Position(..),
-	colorToWord32, Color(..))
+import Graphics.X11.TurtleState(TurtleState(..), SVG(..), Position(..),
+	Color(..))
 import Graphics.X11.TurtleField(
 	Field, Layer, Character,
 	forkIOX, openField, closeField, flushLayer,
@@ -33,8 +33,7 @@
 	drawLine, drawCharacter, drawCharacterAndLine, undoLayer,
 	drawLineNotFlush,
 	clearCharacter, addThread,
-	fieldColor, onkeypress, onclick, onrelease, ondrag, waitField, writeString,
-	Color'(..)
+	fieldColor, onkeypress, onclick, onrelease, ondrag, waitField, writeString
  )
 
 import Control.Concurrent(threadDelay)
@@ -67,18 +66,18 @@
 	when (undo t1 && clear t0) $ drawLines l $ drawed t1
 	when (visible t1) $ do
 		forM_ (getDirections (dir t0) (dir t1)) $ \d -> do
-			drawTurtle c (Color $ pencolor t1) (shape t1) (shapesize t1) d
+			drawTurtle c (pencolor t1) (shape t1) (shapesize t1) d
 				(pensize t1) p0 Nothing
 			threadDelay rotateSpeed
 		forM_ (getPositions x0 y0 x1 y1) $ \p -> do
-			drawTurtle c (Color $ pencolor t1) (shape t1) (shapesize t1)
+			drawTurtle c (pencolor t1) (shape t1) (shapesize t1)
 				(dir t1) (pensize t1) p lineOrigin
 			threadDelay moveSpeed
-		drawTurtle c (Color $ pencolor t1) (shape t1) (shapesize t1) (dir t1)
+		drawTurtle c (pencolor t1) (shape t1) (shapesize t1) (dir t1)
 			(pensize t1) p1 lineOrigin
 	unless (visible t1) $ clearCharacter c
 	when (not (undo t1) && line t1) $
-		drawLine l (pensize t1) (Color $ pencolor t1) x0 y0 x1 y1 >> flushLayer l
+		drawLine l (pensize t1) (pencolor t1) x0 y0 x1 y1 >> flushLayer l
 	when (clear t1) $ clearLayer l >> flushLayer l
 	unless (undo t1) $ drawDraw l (draw t1) >> flushLayer l
 	where
@@ -93,8 +92,8 @@
 drawDraw :: Layer -> Maybe SVG -> IO ()
 drawDraw _ Nothing = return ()
 drawDraw l (Just (Line (Center x0 y0) (Center x1 y1) clr lw)) =
-	drawLineNotFlush l lw (Color $ colorToWord32 clr) x0 y0 x1 y1
--- drawDraw l (Line clr lw (x0, y0) (x1, y1)) = drawLineNotFlush l lw (Color clr) x0 y0 x1 y1
+	drawLineNotFlush l lw clr x0 y0 x1 y1
+-- drawDraw l (Line clr lw (x0, y0) (x1, y1)) = drawLineNotFlush l lw (clr) x0 y0 x1 y1
 drawDraw l (Just (Text (Center x y) sz (RGB r_ g_ b_) fnt str)) =
 -- drawDraw l (Just (Text (r, g, b) fnt sz (x, y) str)) =
 	writeString l fnt sz r g b x y str
@@ -115,7 +114,7 @@
 	where
 	dd = if de > ds then stepDir else - stepDir
 
-drawTurtle :: Character -> Color' -> [Pos] -> Double -> Double -> Double ->
+drawTurtle :: Character -> Color -> [Pos] -> Double -> Double -> Double ->
 	Pos -> Maybe Pos -> IO ()
 drawTurtle c clr sh s d lw (px, py) org = do
 	let sp = map (((+ px) *** (+ py)) . rotatePoint . ((* s) *** (* s))) sh
diff --git a/src/Graphics/X11/TurtleState.hs b/src/Graphics/X11/TurtleState.hs
--- a/src/Graphics/X11/TurtleState.hs
+++ b/src/Graphics/X11/TurtleState.hs
@@ -1,12 +1,9 @@
 module Graphics.X11.TurtleState (
 	TurtleState(..),
 	initialTurtleState,
---	Color,
-	pencolor',
-	pencolor,
+	pencolor_,
 	setPencolor,
 	SVG(..),
---	Draw(..),
 	Position(..),
 	Color(..),
 	colorToWord32
@@ -16,36 +13,11 @@
 import Data.Bits
 import Text.XML.YJSVG
 
-{-
-type Color = Word32
-
-data Draw
-	= NoDraw
-	| Line{
-		color :: Color,
-		width :: Double,
-		begin :: (Double, Double),
-		end :: (Double, Double)
-	 }
-	| Str{
-		scolor :: (Double, Double, Double),
-		font :: String,
-		size :: Double,
-		pos :: (Double, Double),
-		contents :: String
-	 }
-	deriving (Show, Eq)
--}
-
-pencolor' :: TurtleState -> Color
-pencolor' t =
-	RGB (round $ red t * 0xff) (round $ green t * 0xff) (round $ blue t *  0xff)
-
-pencolor :: TurtleState -> Word32
-pencolor t = c
+pencolor_ :: TurtleState -> Word32
+pencolor_ TurtleState{pencolor = RGB r g b} = c'
 	where
-	c = shift (round $ red t * 0xff) 16 .|.
-		shift (round $ green t * 0xff) 8 .|. round (blue t * 0xff)
+	c' = shift (fromIntegral r) 16 .|. shift (fromIntegral g) 8 .|. fromIntegral b
+pencolor_ TurtleState{pencolor = ColorName _} = error "not implemented"
 
 colorToWord32 :: Color -> Word32
 colorToWord32 (RGB r g b) =
@@ -53,12 +25,12 @@
 colorToWord32 _ = error "colorToWord32 (ColorName _) is not implemented"
 
 setPencolor :: TurtleState -> Word32 -> TurtleState
-setPencolor t c = t{red = r, green = g, blue = b}
+setPencolor t c = t{
+	pencolor = RGB r_ g_ b_}
 	where
-	r_ = shiftR c 16 .&. 0xff
-	g_ = shiftR c 8 .&. 0xff
-	b_ = c .&. 0xff
-	[r, g, b] = map ((/ 0xff) . fromIntegral) [r_, g_, b_]
+	r_ = fromIntegral $ shiftR c 16 .&. 0xff
+	g_ = fromIntegral $ shiftR c 8 .&. 0xff
+	b_ = fromIntegral $ c .&. 0xff
 
 data TurtleState = TurtleState {
 	position :: (Double, Double),
@@ -66,9 +38,7 @@
 	degrees :: Double,
 	pendown :: Bool,
 	pensize :: Double,
-	red :: Double,
-	green :: Double,
-	blue :: Double,
+	pencolor :: Color,
 	shape :: [(Double, Double)],
 	shapesize :: Double,
 	visible :: Bool,
@@ -87,9 +57,7 @@
 	degrees = 360,
 	pendown = True,
 	pensize = 0,
-	red = 0,
-	green = 0,
-	blue = 0,
+	pencolor = RGB 0 0 0,
 	shape = sh,
 	shapesize = 1,
 	visible = True,
diff --git a/xturtle.cabal b/xturtle.cabal
--- a/xturtle.cabal
+++ b/xturtle.cabal
@@ -2,7 +2,7 @@
 cabal-version:	>= 1.6
 
 name:		xturtle
-version:	0.0.14
+version:	0.0.15
 stability:	experimental
 author:		Yoshikuni Jujo <PAF01143@nifty.ne.jp>
 maintainer:	Yoshikuni Jujo <PAF01143@nifty.ne.jp>
@@ -30,8 +30,8 @@
 library
   Hs-source-dirs:	src
   Exposed-modules:	Graphics.X11.Turtle
-  Build-depends:	base > 3 && < 5, yjtools >= 0.9.13, convertible, X11,
-    X11-xft <= 3.1, x11-xim, setlocale, yjsvg >= 0.1.9
+  Build-depends:	base > 3 && < 5, yjtools >= 0.9.13, convertible >= 1.0.8, X11,
+    X11-xft <= 3.1, x11-xim, setlocale, yjsvg >= 0.1.11
   Ghc-options:		-Wall
   Other-modules:	Graphics.X11.TurtleField, Graphics.X11.TurtleInput,
     Graphics.X11.TurtleMove, Graphics.X11.TurtleState, Graphics.X11.TurtleShape