[Spiral] Introduce a simpler Rect data type to remove a lot of the fromIntegrals

darcs-hash:20070524100423-db939-055745b5398e184e9e259619c0d776fe8ad14bb3.gz

1 files changed, 27 insertions, 22 deletions

diff --git a/Spiral.hs b/Spiral.hs
index e4cf2d9..ca8f891 100644
--- a/Spiral.hs
+++ b/Spiral.hs
@@ -26,36 +26,41 @@ data Direction = East | South | West | North deriving (Enum)
 
 spiral :: Rational -> Layout
 spiral scale = Layout { doLayout = fibLayout,
-                        modifyLayout = \m -> fmap resize (fromMessage m) }
+                        modifyLayout = \m -> fmap resize $ fromMessage m }
     where
       fibLayout sc ws = return $ zip ws rects
-          where len = length ws
-                ratios = map (* scale) . reverse . take len . mkRatios $ fibs
-                rects = divideRects ratios (cycle [East .. North]) len sc
+          where ratios = map (* scale) . reverse . take (length ws) . mkRatios $ fibs
+                rects = divideRects (zip ratios (cycle [East .. North])) sc
 
       resize Expand = spiral $ (21 % 20) * scale
       resize Shrink = spiral $ (20 % 21) * scale
 
-divideRects :: [Rational] -> [Direction] -> Int -> Rectangle -> [Rectangle]
-divideRects [] _ _ _ = []
-divideRects _ [] _ _ = []
-divideRects (r:rs) (d:ds) n rect | n <= 1 = [rect]
-                                 | otherwise = case divideRect r d rect of
-                                       (r1, r2) -> r1 : (divideRects rs ds (n - 1) r2)
+divideRects :: [(Rational, Direction)] -> Rectangle -> [Rectangle]
+divideRects [] _ = []
+divideRects ((r,d):xs) rect = case divideRect r d rect of
+                                (r1, r2) -> r1 : (divideRects xs r2)
+
+-- It's much simpler if we work with all Integers and convert to
+-- Rectangle at the end.
+data Rect = Rect Integer Integer Integer Integer
+
+fromRect :: Rect -> Rectangle
+fromRect (Rect x y w h) = Rectangle (fromIntegral x) (fromIntegral y) (fromIntegral w) (fromIntegral h)
+
+toRect :: Rectangle -> Rect
+toRect (Rectangle x y w h) = Rect (fromIntegral x) (fromIntegral y) (fromIntegral w) (fromIntegral h)
 
 divideRect :: Rational -> Direction -> Rectangle -> (Rectangle, Rectangle)
-divideRect ratio East (Rectangle x y w h) = let (w1, w2) = chop ratio (fromIntegral w) in
-                                            (Rectangle x y (fromIntegral w1) h,
-                                             Rectangle (x + (fromIntegral w1)) y (fromIntegral w2) h)
-divideRect ratio South (Rectangle x y w h) = let (h1, h2) = chop ratio (fromIntegral h) in
-                                             (Rectangle x y w (fromIntegral h1),
-                                              Rectangle x (y + (fromIntegral h1)) w (fromIntegral h2))
-divideRect ratio West (Rectangle x y w h) = let (w1, w2) = chop (1 - ratio) (fromIntegral w) in
-                                            (Rectangle (x + (fromIntegral w1)) y (fromIntegral w2) h,
-                                             Rectangle x y (fromIntegral w1) h)
-divideRect ratio North (Rectangle x y w h) = let (h1, h2) = chop (1 - ratio) (fromIntegral h) in
-                                             (Rectangle x (y + (fromIntegral h1)) w (fromIntegral h2),
-                                              Rectangle x y w (fromIntegral h1))
+divideRect r d rect = let (r1, r2) = divideRect' r d $ toRect rect in
+                      (fromRect r1, fromRect r2)
+
+divideRect' :: Rational -> Direction -> Rect -> (Rect, Rect)
+divideRect' ratio dir (Rect x y w h) =
+    case dir of
+      East -> let (w1, w2) = chop ratio w in (Rect x y w1 h, Rect (x + w1) y w2 h)
+      South -> let (h1, h2) = chop ratio h in (Rect x y w h1, Rect x (y + h1) w h2)
+      West -> let (w1, w2) = chop (1 - ratio) w in (Rect (x + w1) y w2 h, Rect x y w1 h)
+      North -> let (h1, h2) = chop (1 - ratio) h in (Rect x (y + h1) w h2, Rect x y w h1)
 
 chop :: Rational -> Integer -> (Integer, Integer)
 chop rat n = let f = ((fromIntegral n) * (numerator rat)) `div` (denominator rat) in