bgamari / diagrams-svg

An SVG backend for diagrams

diagrams-svg

diagrams-svg is a an SVG backend for diagrams. Diagrams is a powerful, flexible, declarative domain-specific language for creating vector graphics, using the Haskell programming language.

diagrams-svg is the default out-of-the box backend that comes with the diagrams framework, and supports most features defined in diagrams-lib.

Installation

cabal update && cabal install diagrams-svg

Usage

A simple example that uses diagrams-svg to draw a square.

import Diagrams.Prelude
import Diagrams.Backend.SVG.CmdLine

b1 = square 20 # lw 0.002

main = mainWith (pad 1.1 b1)

Save this to file named Square.hs and compile this program:

ghc --make Square.hs

This will generate an executable which, when run produces an SVG file. Run the executable with the --help option to find out more about how to call it.

$ ./Square --help
./Square

Usage: ./Square [-w|--width WIDTH] [-h|--height HEIGHT] [-o|--output OUTPUT] [--loop] [-s|--src ARG] [-i|--interval INTERVAL]
  Command-line diagram generation.

Available options:
  -?,--help                Show this help text
  -w,--width WIDTH         Desired WIDTH of the output image
  -h,--height HEIGHT       Desired HEIGHT of the output image
  -o,--output OUTPUT       OUTPUT file
  -l,--loop                Run in a self-recompiling loop
  -s,--src ARG             Source file to watch
  -i,--interval INTERVAL   When running in a loop, check for changes every INTERVAL seconds.
  -p,--pretty              Pretty print the SVG output

You must pass an output file name with a .svg extension to generate the SVG file.

$ ./Square -o square.svg

The command above generates the SVG file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
    "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="22.0" height="22.0" viewBox="0 0 22 22">
  <g>
    <g stroke="rgb(0,0,0)" stroke-opacity="1.0" fill="rgb(0,0,0)" fill-opacity="0.0" stroke-width="2.0e-3">
       <path d="M 21.0,21.0 l -2.220446049250313e-15,-20.0 h -20.0 l -2.220446049250313e-15,20.0 Z" />
    </g>
  </g>
</svg>