YAMscgen

Command Line Interface

$ python3 yamscgen.py -h
usage: YAMscgen [-h] [-i INPUT] [-c CSS] -o OUTPUT [-t {svg,png,pdf}]

Generate flexible and customizable sequence diagrams using and extending the synthax of Mscgen:
https://www.mcternan.me.uk/mscgen/.

options:
  -h, --help            show this help message and exit
  -i INPUT, --input INPUT
                        The input file to read from. If omitted, reads from the standard input.
  -c CSS, --css CSS     The css file used to style the output file.
  -o OUTPUT, --output OUTPUT
                        The output file to write to.
  -t {svg,png,pdf}, --type {svg,png,pdf}

Written by Julien Van Roy under supervision of Prof. Bruno Quoitin (UMons). Code available at
https://github.com/JulienVR/YAMscgen.

Runs on any Python version >= 3.8.

Tests

To run all tests :

$ python3 -m unittest discover

To run a particular test:

$ python3 -m unittest test.test_parser.TestParser.test_parse_options

Demonstration

Generating an example file

Copy paste this in a input.txt file. Note that this example also works with Mscgen.

msc {
    # Global options here
    arcgradient="10";
    
    # Entities here
    a [label="Entity A", textbgcolor="#82b366"],
    b [label="Entity B", textbgcolor="grey"],
    c [label="Entity C", textbgcolor="#d79b00"];
    
    # Arcs, boxes
    
    # A line finishes with ';'
    a => b [label="First call"];
    
    # Several elements can be aligned
    b => b [label="Processing...", textbgcolor="yellow"], 
    c note c [label="Several elements\ncan be on the\nsame line", textbgcolor="#dae8fc"];
    
    c -> b [label="Another arc type"];
    b >> a [label="A dashed arc\nis useful here"],
    c rbox c [label="This is another\ntype of comment", textbgcolor="#dae8fc"];
    
    ... [label="Time flies...", textcolor="blue"];
    
    a -x b [label="And this is an\nlost arc"];
    a -> c [label="Last call", linecolor="red"];
}

Run:

$ python3 yamscgen.py -i input.txt -o out.svg

The SVG obtained is as shown below:

Fonts

You can use any font from Courier, Helvetica, Times.

Set the font globally, e.g. font="Helvetica";. You can also set the font on a given element, e.g. a->b [label="test", font-family="Courier"].

The reason font-family is used on the element level is that it is the name of the SVG attribute for a text node. You can also pass any SVG attribute to the elements, they will be passed to the SVG. For instance: font-weight="bold" or font-style="italic".

Splitting on multiple files

Add max-height="250" to the global options in the input.txt to obtain:

msc {
    # Global options here
    arcgradient="10", max-height="250";
    
    # Entities here
    a [label="Entity A", textbgcolor="#82b366"],
    b [label="Entity B", textbgcolor="grey"],
    c [label="Entity C", textbgcolor="#d79b00"];
    
    # Arcs, boxes
    
    # A line finishes with ';'
    a=>b [label="First call"];
    
    # Several elements can be aligned
    b=>b [label="Processing...", textbgcolor="yellow"], 
    c note c [label="Several elements\ncan be on the\nsame line", textbgcolor="#dae8fc"];
    
    c -> b [label="Another arc type"];
    b >> a [label="A dashed arc\nis useful here"],
    c rbox c [label="This is another\ntype of comment", textbgcolor="#dae8fc"];
    
    ... [label="Time flies...", textcolor="blue"];
    
    a:>b [label="And this is an\nemphasized arc"];
    a->c [label="Last call", linecolor="red"];
}

After running again $ python3 yamscgen.py -i input.txt -o out.svg, 2 diagrams should have been created.

Adding a CSS file

Copy paste this in a template.css file.

/* color the lifeline of A in green */
.lifelines > line.a, g.participants  > rect.a{
    stroke: green;
}

/* color the lifeline of B in blue */
.lifelines > line.b, g.participants  > rect.b {
    stroke: blue;
}

/* color the arcs */
.elements > line, .elements > path,  .elements > rect {
    stroke: orange;
}

/* color the tip of the arrows */
defs path {
    stroke: orange;
    fill: orange;
}

/* highlight all labels of the 4th line */
#line-4 .label > rect {
    fill: greenyellow;
}

Run:

$ python3 yamscgen.py -i input.txt -c template.css -o out.svg

The SVG obtained is as shown below: