A simple tool to generate Sankey diagrams from text input.

• Text in, SVG out
• Supports circular graphs, cycles are drawn with back edges
• Optimizes layout to minimize edge crossings
• Standalone application works offline

The program reads the graph definition from STDIN and writes the SVG output to STDOUT. Error messages and warnings are written to STDERR.

$ cat input.txt | riall > output.svg

The input file contains one line per edge. Each such line contains the source node, the weight of the edge (enclosed in square brackets) and the target node. The nodes can be any string that does not contain whitespace or square brackets.

First Node [123] Second Node
Second Node [456] Finito

Any line starting with // or # is considered a comment and is ignored. The file can also contain empty lines. These are ignored as well.

The default style of elements can be customized by adding configuration lines as the following. For node properties:

set node.background blue
set node.stroke.color white
set node.stroke.width 1
set node.width 8
set node.opacity 1.0
set node.shape.rx 3
set node.shape.ry 3
set node.label.align center
set node.label.background rgba(255,255,255,0.2)

For edge properties:

set edge.background #ffadef
set edge.stroke.color #000000
set edge.stroke.width 1
set edge.opacity 0.7

Edge background can be source, target, gradient, or a color value.

For the whole canvas:

set canvas.background #ffffff
set canvas.width 800
set canvas.height 600
set canvas.margin 10

The program produces SVG output. This can be easily converted to other formats using the convert command from the ImageMagick as such: cat input.txt | riall | convert svg:- output.png

Contributions are welcome. Please open an issue or a pull request.

This project is released under the permissive MIT license. See LICENSE for details.