Add transform-origin rule.

Author: alexmingoia

src/CSS/Transform.purs

@@ -1,13 +1,13 @@
 module CSS.Transform where
 
 import Prelude
-
-import Data.Generic (class Generic)
-
-import CSS.Property (class Val, Value, value, noCommas)
+import CSS.Common (class Inherit, class Initial, class Unset)
+import CSS.Property (class Val, Value, noCommas, value)
 import CSS.Size (Angle, Abs, Size)
 import CSS.String (fromString)
 import CSS.Stylesheet (CSS, key)
+import Data.Generic (class Generic)
+import Data.Tuple.Nested (tuple3)
 
 newtype Transformation = Transformation Value
 
@@ -29,3 +29,61 @@ translate x y = Transformation $ fromString "translate(" <> value [x, y] <> from
 
 rotate :: forall a. Angle a -> Transformation
 rotate a = Transformation $ fromString "rotate(" <> value a <> fromString ")"
+
+data TransformOrigin a
+  = TransformOrigin (TransformOriginOffset a) (TransformOriginOffset a) (Size a)
+  | Initial
+  | Inherit
+  | Unset
+
+data TransformOriginOffset a
+  = OffsetLength (Size a)
+  | OffsetTop
+  | OffsetBottom
+  | OffsetLeft
+  | OffsetRight
+  | OffsetCenter
+
+instance valTransformOriginOffset :: Val (TransformOriginOffset a) where
+  value (OffsetLength s) = value s
+  value (OffsetTop) = fromString "top"
+  value (OffsetBottom) = fromString "bottom"
+  value (OffsetLeft) = fromString "left"
+  value (OffsetRight) = fromString "right"
+  value (OffsetCenter) = fromString "center"
+
+instance valTransformOrigin :: Val (TransformOrigin a) where
+  value (TransformOrigin x y z) = value (tuple3 x y z)
+  value (Initial) = fromString "initial"
+  value (Inherit) = fromString "inherit"
+  value (Unset) = fromString "unset"
+
+instance initialTransformOrigin :: Initial (TransformOrigin a) where
+  initial = Initial
+
+instance inheritTransformOrigin :: Inherit (TransformOrigin a) where
+  inherit = Inherit
+
+instance unsetTransformOrigin :: Unset (TransformOrigin a) where
+  unset = Unset
+
+offset :: forall a. Size a -> TransformOriginOffset a
+offset = OffsetLength
+
+offsetTop :: forall a. TransformOriginOffset a
+offsetTop = OffsetTop
+
+offsetBottom :: forall a. TransformOriginOffset a
+offsetBottom = OffsetBottom
+
+offsetLeft :: forall a. TransformOriginOffset a
+offsetLeft = OffsetLeft
+
+offsetRight :: forall a. TransformOriginOffset a
+offsetRight = OffsetRight
+
+offsetCenter :: forall a. TransformOriginOffset a
+offsetCenter = OffsetCenter
+
+transformOrigin :: forall a. TransformOriginOffset a -> TransformOriginOffset a -> Size a -> CSS
+transformOrigin x y z = key (fromString "transform-origin") (TransformOrigin x y z)