Replace bresenham with digitalLine

src/Geometry.hs

@@ -297,6 +297,7 @@ divideLine x a b = take 5000 $ map (\i -> a +.+ (i / (fromIntegral numPoints) *.
 
 
 -- pulled the following from the haskell wiki
+-- it seems to produce an infinite loop sometimes
 bresenham :: (Int,Int) -> (Int,Int) -> [(Int,Int)]
 {-# INLINE bresenham #-}
 bresenham pa@(xa,ya) pb@(xb,yb) = map maySwitch . unfoldr go $ (x1,y1,0)
@@ -316,6 +317,18 @@ bresenham pa@(xa,ya) pb@(xb,yb) = map maySwitch . unfoldr go $ (x1,y1,0)
                             then (yTemp+ystep,tempError-deltax)
                             else (yTemp,tempError)
 
+digitalLine :: (Int,Int) -> (Int,Int) -> [(Int,Int)]
+digitalLine (x1,y1) (x2,y2) 
+    | abs (x1-x2) > abs (y1-y2) = [ (x,( (y1-y2) * x + x1*y2 - x2*y1) `rdiv` (x1-x2) ) 
+                                    | x <- intervalList x1 x2 ]
+    | otherwise                 = [ ( ((x1-x2) * y + y1*x2 - y2*x1) `rdiv` (y1-y2)  , y)
+                                    | y <- intervalList y1 y2 ]
+        where rdiv a b = round $ fromIntegral a / fromIntegral b
+
+intervalList :: Int -> Int -> [Int]
+intervalList x y 
+    | y >= x = [x .. y]
+    | otherwise = reverse [y..x]
 
 divideCircle :: Float -> Point2 -> Float -> [Point2]
 divideCircle x cen rad = map (cen +.+) $ nPointsOnCirc n rad