diff --git a/gruff.cabal b/gruff.cabal
--- a/gruff.cabal
+++ b/gruff.cabal
@@ -1,16 +1,23 @@
 Name:                gruff
-Version:             0.3
+Version:             0.3.1
 Synopsis:            fractal explorer GUI using the ruff library
 Description:
     Mandelbrot Set fractal explorer using the ruff library.
     .
     Requires GTK, OpenGL, and GLSL fragment shader support; lots of RAM
-    and multiple CPU cores recommended.  If you want to explore very deep
-    zooms, you'll need hmpfr which currently requires GHC to be compiled
-    with integer-simple instead of the default integer-gmp.  To install
-    with MPFR support, use @cabal install gruff -fmpfr@.  (Note that the
-    default setting for this flag has changed since the previous release.)
+    and multiple CPU cores recommended.
     .
+    If you want to explore very deep zooms, you'll need hmpfr which
+    currently requires GHC to be compiled with integer-simple instead of
+    the default integer-gmp.  To install with MPFR support, use
+    @cabal install gruff -fmpfr@.
+    Note that the default setting for this flag has changed since gruff-0.2.
+    .
+    gruff-0.3.1 is a bugfix release, fixing a performance problem wherein
+    offscreen tiles were needlessly calculated.  The performance gain
+    is much less (and in many cases is in fact a performance loss) when
+    using integer-simple.
+    .
     gruff-0.3 includes a small library to allow external programs to
     create diagrams and animations with gruff.  See the gruff-examples
     package.  The interface has been remodelled to simplify it and add
@@ -102,7 +109,7 @@
                       Tile
                       Utils
                       View
-  Build-depends:      gruff == 0.3,
+  Build-depends:      gruff == 0.3.1,
                       base >= 4 && < 5,
                       containers >= 0 && < 1,
                       directory >= 1 && < 2,
@@ -137,4 +144,4 @@
 source-repository this
   type:     git
   location: git://gitorious.org/ruff/gruff.git
-  tag:      v0.3
+  tag:      v0.3.1
diff --git a/src/View.hs b/src/View.hs
--- a/src/View.hs
+++ b/src/View.hs
@@ -14,11 +14,12 @@
 import Data.Bits (bit)
 import Data.Ratio ((%))
 
-import Fractal.RUFF.Types.Complex (Complex((:+)))
+import Fractal.RUFF.Types.Complex (Complex((:+)), magnitude)
 
 import Fractal.GRUFF
 
-import QuadTree (Quad(..), Child(..), child)
+import QuadTree (Quad(..), Child(..), child, Square(..), square)
+import Tile (rootSquare)
 
 pixelLocation :: Window -> Viewport -> Location -> Double -> Double -> Complex Rational
 pixelLocation w v l = let f = fromScreenCoords w v l in \x y -> f (x :+ y)
@@ -118,25 +119,25 @@
 visibleQuads :: Window -> Viewport -> Location -> Int -> Maybe ([(Complex Int, Quad)], [(Complex Int, Quad)])
 visibleQuads w v l o = do
   let b = bufferSize o w
-      a = orient v
-      co = cos a
-      si = sin a
-      k = 0.5 ** (delta l - fromIntegral o)
-      x1 = k * fromIntegral (width  w)
-      y1 = k * fromIntegral (height w)
-      x0 = - x1
-      y0 = - y1
-      visible t (i :+ j, _) =
-        let d = if t then texels b else texels b `div` 2
-        in  not . and $
-              [ x < x0 || y < y0 || x1 < x || y1 < y
-              | di <- [0, 1], let i' = fromIntegral (i - d + di * tileSize)
-              , dj <- [0, 1], let j' = fromIntegral (j - d + dj * tileSize)
-              , let x =  co * i' + si * j', let y = -si * i' + co * j'
-              ]
+      x0 = 0
+      y0 = 0
+      x1 = fromIntegral (width  w)
+      y1 = fromIntegral (height w)
+      toScreen = toScreenCoords w v l
+      visible (_, q) =
+        let s = square rootSquare q
+            d = squareSize s / 2
+            r  = magnitude $ p - p0
+            c0 =  squareWest s      :+  squareNorth s
+            c  = (squareWest s + d) :+ (squareNorth s + d)
+            p0         = toScreen c0
+            p@(x :+ y) = toScreen c
+        in  not $ x < x0 - r || y < y0 - r || x1 + r < x || y1 + r < y
   qs0 <- bufferQuads l b
-  let qs1 = concatMap childQuads qs0
-  return ( filter (visible False) qs0 , filter (visible True) qs1 )
+  let qs0' = filter visible qs0
+      qs1 = concatMap childQuads qs0'
+      qs1' = filter visible qs1
+  return (qs0', qs1')
 
 defImage :: Image
 defImage = Image