A pandoc filter to express diagrams inline using the haskell EDSL diagrams.
Create an input file called demo.md with the following text:
This is how to draw a circle:
~~~ diagram
example = circle 1
~~~Install diagrams-pandoc, then run pandoc as follows:
pandoc -t html demo.md --filter diagrams-pandoc -o demo.html -sThe file demo.html should now have an img tag pointing at a PNG of a circle.
You can specify attributes to control how the diagram is generated. The following, for example,
~~~ {.diagram width=800 height=400 caption="A circle"}
example = circle 1
~~~will override the default width and height of the generated diagram, and provide a caption for it. The following attributes are supported:
width: The width of the generated diagram, in pixels. The default is 500.height: The height of the generated diagram, in pixels. The default is 200.caption: The caption of the diagram. Providing a caption makes the diagram appear as a figure, rather than an inline image. Diagrams have no caption by default.alt: The alt text of the diagram. The caption is used as the default value if it is provided, otherwise it is empty.
diagrams-pandoc compiles code blocks containing diagrams expressions
and includes the resulting images in the pandoc markup. It is meant
to be run as a
pandoc filter as
shown above.
diagrams-pandoc evaluates the diagrams expression example by
default. This can be modified by passing a command line argument.
diagrams-pandoc is aware of two code block classes. A block with
the diagram class will be replaced by the resulting image---the code
will not appear in the output. A block with the diagram-haskell
class will produce both an image and a (syntax highlighted) code
block. The input block is replaced by image appears before the code
block, and the diagram-haskell class is replaced by the haskell
class, so that pandoc can perform syntax highlighting as usual.
diagrams-pandoc produces images in the pdf format when used with
the latex and beamer writers of pandoc and produced png output
otherwise.
I have only tested with pandoc's markdown reader. In particular, the rst reader does not attach classes to code blocks, only to Div elements.
diagrams-pandoc is on Hackage. To install, run cabal install diagrams-pandoc
- use pandoc output type to pick an image file format
- for formats which are more human-readable (eg, markdown, rst), leave code block alone?
- provide command-line flags to override default behavior
- add Backends besides Cairo
- Support RST by handling
Div class=diagram [CodeBlock foo bar]the same asCodeBlock class=diagram bar - Alternate install directions using
stack
