Implement setLineJoin

Author: rgrempel

docs/Graphics/Canvas.md

@@ -228,6 +228,25 @@ setLineCap :: forall eff. LineCap -> Context2D -> Eff (canvas :: Canvas | eff) C
 
 Set the current line cap type.
 
+#### `LineJoin`
+
+``` purescript
+data LineJoin
+  = BevelJoin
+  | RoundJoin
+  | MiterJoin
+```
+
+Enumerates the different types of line join
+
+#### `setLineJoin`
+
+``` purescript
+setLineJoin :: forall eff. LineJoin -> Context2D -> Eff (canvas :: Canvas | eff) Context2D
+```
+
+Set the current line join type.
+
 #### `Composite`
 
 ``` purescript

src/Graphics/Canvas.js

@@ -146,6 +146,15 @@ exports.setLineCapImpl = function(cap) {
     };
 };
 
+exports.setLineJoinImpl = function(join) {
+    return function(ctx) {
+        return function() {
+            ctx.lineJoin = join;
+            return ctx;
+        };
+    };
+};
+
 exports.setGlobalCompositeOperationImpl = function(ctx) {
     return function(op) {
         return function() {

src/Graphics/Canvas.purs

@@ -11,6 +11,7 @@ module Graphics.Canvas
   , Composite(..)
   , Dimensions()
   , LineCap(..)
+  , LineJoin(..)
   , Rectangle()
   , ScaleTransform()
   , TextMetrics()
@@ -44,6 +45,7 @@ module Graphics.Canvas
   , setShadowColor
 
   , setLineCap
+  , setLineJoin
   , setGlobalCompositeOperation
   , setGlobalAlpha
 
@@ -213,6 +215,19 @@ setLineCap Round  = setLineCapImpl "round"
 setLineCap Square = setLineCapImpl "square" 
 setLineCap Butt   = setLineCapImpl "butt"
 
+-- Note that we can't re-use `Round` from LineCap, so I've added `Join` to all of these
+
+-- | Enumerates the different types of line join
+data LineJoin = BevelJoin | RoundJoin | MiterJoin
+
+foreign import setLineJoinImpl :: forall eff. String -> Context2D -> Eff (canvas :: Canvas | eff) Context2D
+
+-- | Set the current line join type.
+setLineJoin :: forall eff. LineJoin -> Context2D -> Eff (canvas :: Canvas | eff) Context2D
+setLineJoin BevelJoin = setLineJoinImpl "bevel"
+setLineJoin RoundJoin = setLineJoinImpl "round"
+setLineJoin MiterJoin = setLineJoinImpl "miter"
+
 -- | Enumerates the different types of composite operations and blend modes.
 data Composite
   -- Composite Operations