ALGO: implement the quad tree

Graphics/Diagram/Gtk.hs

@@ -18,6 +18,10 @@ diag p obj@(Object _)
   | alg p == 1 =
       mkDiag (mconcat [convexHPText, convexHP, convexHLs, coordPoints, plotterBG])
              p obj
+  | alg p == 4 =
+      mkDiag (mconcat [squares, coordPointsText, coordPoints, polyLines,
+                       plotterBG])
+             p obj
   | otherwise = mempty
 diag p objs@(Objects _)
   | alg p == 2 =

Graphics/Diagram/Plotter.hs

@@ -4,11 +4,13 @@ module Graphics.Diagram.Plotter where
 
 import Algebra.VectorTypes
 import Algorithms.ConvexHull.GrahamScan
+import Algorithms.RangeSearch.Core
 import Algorithms.PolygonIntersection.Core
 import Data.Monoid
 import Diagrams.Backend.Cairo
 import Diagrams.Prelude hiding ((<>))
 import Graphics.Diagram.Types
+import Graphics.Gloss.Data.Extent
 
 
 -- |Creates a Diagram that shows the coordinates from the points
@@ -33,6 +35,7 @@ pointToTextCoord :: PT -> Diagram Cairo R2
 pointToTextCoord pt =
   text ("(" ++ (show . trim') x ++ ", " ++ (show . trim') y ++ ")") # scale 10
   where
+    trim' :: Double -> Double
     trim' x' = (fromInteger . round $ x' * (10^2)) / (10.0^^2)
     (x, y) = unp2 pt
 
@@ -165,6 +168,26 @@ convexHStepsLs = GifDiag chs
           (strokeTrail . fromVertices $ vt') # moveTo (head vt') # lc col
 
 
+-- FIXME: hardcoded dimensions
+squares :: Diag
+squares = Diag f
+  where
+    f p (Object []) = mempty
+    f p (Object vt) =
+      mconcat
+      $ (\((xmin, xmax), (ymin, ymax)) -> rect (xmax - xmin) (ymax - ymin) #
+        moveTo (p2 (
+                     ((xmax + xmin) / 2),
+                     ((ymax + ymin) / 2)
+                   )
+               ) #
+        lw ultraThin)
+      <$> (quadTreeSquares ((0,500), (0,500)) . quadTree vtf $ (dX p, dY p))
+      where
+        vtf = filterValidPT p vt
+    f _ _ = mempty
+
+
 -- |Creates a Diagram that shows an XAxis which is bound
 -- by the dimensions given in xD from DiagProp.
 xAxis :: Diag