VEC: Fix the inRange function

It now takes a PROPER square, as in ((xmin, ymin), (xmax, ymax))
instead of ((xmin, xmax), (ymin, ymax)) and also works
with negative values.

Because the meaning of the arguments has changed, we also
had to fix all uses of it.

Graphics/Diagram/Core.hs

@@ -35,9 +35,9 @@ data DiagProp = MkProp {
   -- |The thickness of the dots.
   dotSize :: Double,
   -- |The dimensions of the x-axis.
-  xDimension :: Coord,
+  xDimension :: (Double, Double),
   -- |The dimensions of the y-axis.
-  yDimension :: Coord,
+  yDimension :: (Double, Double),
   -- |Algorithm to use.
   algo :: Int,
   -- |If we want to show the grid.
@@ -135,7 +135,14 @@ maybeDiag b d
 
 
 filterValidPT :: DiagProp -> [PT] -> [PT]
-filterValidPT p = filter (inRange (xDimension p, yDimension p))
+filterValidPT =
+  filter
+  . inRange
+  . diagDimSquare
+
+
+diagDimSquare :: DiagProp -> Square
+diagDimSquare p = dimToSquare (xDimension p) $ yDimension p
 
 
 -- |Draw a list of points.
@@ -154,9 +161,13 @@ drawP vt ds =
 rectByDiagonal :: (Double, Double)  -- ^ sw point
                -> (Double, Double)  -- ^ nw point
                -> Diagram Cairo R2
-rectByDiagonal (xmin, xmax) (ymin, ymax) =
-  rect (xmax - xmin) (ymax - ymin)
-    # moveTo (p2 ((xmax + xmin) / 2, (ymax + ymin) / 2))
+rectByDiagonal (xmin, ymin) (xmax, ymax) =
+  fromVertices [p2 (xmin, ymin)
+                , p2 (xmax, ymin)
+                , p2 (xmax, ymax)
+                , p2 (xmin, ymax)
+                , p2 (xmin, ymin)
+               ]
 
 
 -- |Creates a Diagram from a point that shows the coordinates