From 844b1002c3b228c949aa9d720eb4320916dd3102 Mon Sep 17 00:00:00 2001
From: Christopher Chalmers <c.chalmers@me.com>
Date: Tue, 24 Feb 2015 22:37:45 +0000
Subject: [PATCH] Fix facingAB projections.

---
 src/Diagrams/LinearMap.hs         | 13 ++++++-------
 src/Diagrams/ThreeD/Projection.hs |  7 +++++--
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/Diagrams/LinearMap.hs b/src/Diagrams/LinearMap.hs
index d7fad1a0..8364156c 100644
--- a/src/Diagrams/LinearMap.hs
+++ b/src/Diagrams/LinearMap.hs
@@ -22,7 +22,7 @@
 
 module Diagrams.LinearMap where
 
-import           Control.Lens            hiding (lmap)
+import           Control.Lens
 import           Data.FingerTree         as FT
 import           Data.Foldable           (Foldable)
 
@@ -57,12 +57,11 @@ class LinearMappable a b where
 -- r ~ A u m => LinearMappable (A v n) r
 --
 -- so ghc knows there's only one possible result from calling vmap.
--- I can't think of a better way to set up the class.
 
 -- | Apply a linear map.
-lmap :: (InSpace v n a, Foldable v, LinearMappable a b, N b ~ n)
+linmap :: (InSpace v n a, Foldable v, LinearMappable a b, N b ~ n)
      => LinearMap v (V b) n -> a -> b
-lmap = vmap . lapply
+linmap = vmap . lapply
 
 instance r ~ Offset c u m => LinearMappable (Offset c v n) r where
   vmap f (OffsetClosed v) = OffsetClosed (f v)
@@ -125,7 +124,7 @@ toAffineMap t = AffineMap (toLinearMap t) (transl t)
 class (LinearMappable a b, N a ~ N b) => AffineMappable a b where
   amap :: (Additive (V a), Foldable (V a), Additive (V b), Num (N b))
        => AffineMap (V a) (V b) (N b) -> a -> b
-  amap (AffineMap f _) = lmap f
+  amap (AffineMap f _) = linmap f
   {-# INLINE amap #-}
 
 instance r ~ Offset c u n => AffineMappable (Offset c v n) r
@@ -135,7 +134,7 @@ instance (Metric v, Metric u, OrderedField n, r ~ Trail' l u n) => AffineMappabl
 instance (Metric v, Metric u, OrderedField n, r ~ Trail u n) => AffineMappable (Trail v n) r
 
 instance (Additive v, Foldable v, Num n, r ~ Point u n) => AffineMappable (Point v n) r where
-  amap (AffineMap f v) p = lmap f p .+^ v
+  amap (AffineMap f v) p = linmap f p .+^ v
   {-# INLINE amap #-}
 
 instance r ~ FixedSegment u n => AffineMappable (FixedSegment v n) r where
@@ -144,7 +143,7 @@ instance r ~ FixedSegment u n => AffineMappable (FixedSegment v n) r where
   {-# INLINE amap #-}
 
 instance (LinearMappable a b, N a ~ N b, r ~ Located b) => AffineMappable (Located a) r where
-  amap m@(AffineMap l _) (Loc p x) = Loc (amap m p) (lmap l x)
+  amap m@(AffineMap l _) (Loc p x) = Loc (amap m p) (linmap l x)
   {-# INLINE amap #-}
 
 instance (Metric v, Metric u, OrderedField n, r ~ Path u n)
diff --git a/src/Diagrams/ThreeD/Projection.hs b/src/Diagrams/ThreeD/Projection.hs
index 7bd37044..f03fb47e 100644
--- a/src/Diagrams/ThreeD/Projection.hs
+++ b/src/Diagrams/ThreeD/Projection.hs
@@ -78,12 +78,15 @@ import           Linear.Projection
 
 -- Parallel projections
 
+-- | Look at the xy-plane with y as the up direction.
 facingXY :: (Epsilon n, Floating n) => AffineMap V3 V2 n
-facingXY = lookingAt unitX origin zDir
+facingXY = lookingAt unitZ origin yDir
 
+-- | Look at the xz-plane with z as the up direction.
 facingXZ :: (Epsilon n, Floating n) => AffineMap V3 V2 n
-facingXZ = lookingAt unitY origin yDir
+facingXZ = lookingAt unitY origin zDir
 
+-- | Look at the yz-plane with z as the up direction.
 facingYZ :: (Epsilon n, Floating n) => AffineMap V3 V2 n
 facingYZ = lookingAt unitX origin zDir