New builder

examples/Pentaflake.lhs

@@ -1,36 +1,32 @@
-> {-# LANGUAGE NoMonomorphismRestriction #-}
 > import Diagrams.Prelude
-> import qualified Data.Colour as C
 > import Diagrams.Backend.SVG.CmdLine
 
 We can use the [`colour`
 library](http://hackage.haskell.org/package/colour) to generate
 successively lighter shades of blue:
 
-> colors = iterate (C.blend 0.1 white) blue
+> colors = iterate (blend 0.1 white) blue
 
 An order-0 pentaflake is just a pentagon:
 
-> p = regPoly 5 1 # lw 0
-> 
-> pentaflake 0 = p
+> pentaflake' 0 = pentagon 1 # lw 0
 
-An [order-n pentaflake](http://mathworld.wolfram.com/Pentaflake.html) is an order-(n-1) pentaflake surrounded by five
-more.  The `appends` function is useful here for positioning the five
-pentaflakes around the central one.
+An [order-n pentaflake](http://mathworld.wolfram.com/Pentaflake.html) is
+an order-(n-1) pentaflake surrounded by five more. The `appends`
+function is useful here for positioning the five pentaflakes around the
+central one.
 
-> pentaflake n = appends (p' # fc (colors !! (n-1)))
+> pentaflake' n = appends (p' # fc (colors !! (n-1)))
 >                        (zip vs (repeat (rotateBy (1/2) p')))
 >   where vs = take 5 . iterate (rotateBy (1/5))
 >                     . (if odd n then negated else id) $ unitY
->         p' = pentaflake (n-1)
-> 
-> pentaflake' n = pentaflake n # fc (colors !! n)
+>         p' = pentaflake' (n-1)
+>
+> pentaflake n = pentaflake' n # fc (colors !! n)
 
-An order-4 pentaflake looks nice.  Of course there's an exponential
+An order-4 pentaflake looks nice. Of course there's an exponential
 blowup in the number of primitives, so generating higher-order
 pentaflakes can take a long time!
 
-> example :: Diagram B
-> example = pad 1.1 $ pentaflake' 4
+> example = pentaflake 4
 > main = defaultMain (pad 1.1 example)

src/Diagrams/Backend/SVG.hs

@@ -129,6 +129,7 @@ import           Diagrams.TwoD.Adjust         (adjustDia2D)
 import           Diagrams.TwoD.Attributes     (splitTextureFills)
 import           Diagrams.TwoD.Path           (Clip (Clip))
 import           Diagrams.TwoD.Text
+import           Diagrams.Backend.Build
 
 -- from lucid-svg
 import           Lucid.Svg
@@ -223,6 +224,12 @@ instance SVGFloat n => Backend SVG V2 n where
 
   adjustDia c opts d = adjustDia2D sizeSpec c opts (d # reflectY)
 
+instance SVGFloat n => BackendBuild SVG V2 n where
+  outputSize = sizeSpec
+  saveDia outFile opts dia = renderToFile outFile build
+    where
+      build = renderDia SVG opts dia
+
 toRender :: forall n. SVGFloat n => RTree SVG V2 n Annotation -> Render SVG V2 n
 toRender = fromRTree
   . Node (RStyle (mempty # recommendFillColor (transparent :: AlphaColour Double)))

src/Diagrams/Backend/SVG/CmdLine.hs

@@ -73,7 +73,8 @@ module Diagrams.Backend.SVG.CmdLine
 
 import           Diagrams.Backend.CmdLine
 import           Diagrams.Backend.SVG
-import           Diagrams.Prelude               hiding (height, interval, width, output)
+import           Diagrams.Prelude               hiding (height, interval,
+                                                 output, width)
 
 import           Control.Lens                   hiding (argument)
 import           Options.Applicative            hiding ((<>))
@@ -148,7 +149,7 @@ import           Data.List.Split
 -- $ ./MyDiagram -o image.svg -w 400
 -- @
 
-defaultMain :: SVGFloat n => QDiagram SVG V2 n Any -> IO ()
+defaultMain :: Diagram SVG -> IO ()
 defaultMain = mainWith
 
 newtype PrettyOpt = PrettyOpt {isPretty :: Bool}
@@ -162,10 +163,11 @@ instance Parseable PrettyOpt where
   parser = prettyOpt
 
 instance SVGFloat n => Mainable (QDiagram SVG V2 n Any) where
-    type MainOpts (QDiagram SVG V2 n Any) = (DiagramOpts, DiagramLoopOpts, PrettyOpt)
-    mainRender (opts, loopOpts, pretty) d = do
-        chooseRender opts pretty d
-        defaultLoopRender loopOpts
+
+  type MainOpts (QDiagram SVG V2 n Any) = (DiagramOpts, DiagramLoopOpts, PrettyOpt)
+  mainRender (opts, loopOpts, pretty) d = do
+      chooseRender opts pretty d
+      defaultLoopRender loopOpts
 
 chooseRender :: SVGFloat n => DiagramOpts -> PrettyOpt -> QDiagram SVG V2 n Any -> IO ()
 chooseRender opts pretty d =
@@ -206,3 +208,4 @@ instance SVGFloat n => Mainable [(String,QDiagram SVG V2 n Any)] where
         = (MainOpts (QDiagram SVG V2 n Any), DiagramMultiOpts)
 
     mainRender = defaultMultiMainRender
+