diagrams-svg-1.0: SVG backend for diagrams drawing EDSL.

Safe HaskellNone



A full-featured rendering backend for diagrams producing SVG files, implemented natively in Haskell (making it easy to use on any platform).

To invoke the SVG backend, you have three options.

  • You can use the Diagrams.Backend.SVG.CmdLine module to create standalone executables which output SVG images when invoked.
  • You can use the renderSVG function provided by this module, which gives you more flexible programmatic control over when and how images are output (making it easy to, for example, write a single program that outputs multiple images, or one that outputs images dynamically based on user input, and so on).
  • For the most flexibility (e.g. if you want access to the resulting SVG value directly in memory without writing it to disk), you can manually invoke the renderDia method from the Backend instance for SVG. In particular, renderDia has the generic type
 renderDia :: b -> Options b v -> QDiagram b v m -> Result b v

(omitting a few type class constraints). b represents the backend type, v the vector space, and m the type of monoidal query annotations on the diagram. Options and Result are associated data and type families, respectively, which yield the type of option records and rendering results specific to any particular backend. For b ~ SVG and v ~ R2, we have

 data Options SVG R2 = SVGOptions
                       { size :: SizeSpec2D   -- ^ The requested size.
                       , svgDefinitions :: Maybe S.Svg
                       -- ^ Custom definitions that will be added to the @defs@
                       --  section of the output.
 data family Render SVG R2 = R SvgRenderM
 type family Result SVG R2 = Svg

So the type of renderDia resolves to

 renderDia :: SVG -> Options SVG R2 -> QDiagram SVG R2 m -> Svg

which you could call like renderDia SVG (SVGOptions (Width 250)) myDiagram. (In some situations GHC may not be able to infer the type m, in which case you can use a type annotation to specify it; it may be useful to simply use the type synonym Diagram SVG R2 = QDiagram SVG R2 Any.) This returns an Svg value, which you can, e.g. render to a ByteString using renderSvg.



data SVG Source

SVG is simply a token used to identify this rendering backend (to aid type inference).



type B = SVGSource

data family Options b1 v1

Backend-specific rendering options.

renderSVG :: FilePath -> SizeSpec2D -> Diagram SVG R2 -> IO ()Source

Render a diagram as an SVG, writing to the specified output file and using the requested size.