3.2. Saving pipeline configurations

Sometimes it can be useful to store the configuration of the pipeline for later reuse. Writing long configurations in a terminal may also be quite annoying. For these reasons, Boing lets users to write the configuration of the pipeline in a text file and then to load such configuration using the special node conf:.

As an example, consider you have finally wrote the configuration of a pipeline for comparing the result of different smoothing filters. Now you want to save it in a file (e.g. config-filters.txt) and maybe you want to add some comments that will help you understanding the structure of the pipeline. The file may look like the following:

# Pipeline for comparing the result of different smoothing filters.
#
# Author: Me
# Date: Sept 12, 2012
# File: config-filters.txt

# ONE INPUT: a standard TUIO source
in.tuio://:3333

# PARALLEL BRANCHES
+ (
    # Raw input
    nop:

    # Default filter
    | filtering: + edit:?source=Default

    # Moving mean filter
    | filtering:/moving/average?winsize=5 + edit:?source=Mean

    # Moving median filter
    | filtering:/moving/median?winsize=5 + edit:?source=Median

    # Exponential double filter
    | filtering:/exponential/double?alpha=1&gamma=1 + edit:?source=Exponential

    # OneEuro filter
    | filtering:/oneeuro?freq=1 + edit:?source=OneEuro
    # ---
  )

# ONE OUTPUT: the visualizer
+ viz:

Now, in order to run the pipeline you just have to enter the command:

boing conf:./config-filters.txt

Quite easy, isn’t it?

The node conf: is actually a composite node that contains the pipeline defined in the configuration file. For this reason, it is also possible to use the conf: node into another pipeline. Consider as an example that you have a multi-touch table sending contact information via the TUIO protocol, you found a good smoothing filter since the input is quite noisy and you also determined the calibration matrix to fit the touch position to the correct screen space. You are not going to change these parameters so you would like to consider all these elements as an atomic input source that does not mess up a larger configuration. Thus, first you could write the configuration of your input source into a file (e.g. my-mt-table.txt), which may look like the following:

# My multi-touch table without its ugly noise and well calibrated.
#
# Author: Me
# Date: Sept 12, 2012
# File: my-mt-table.txt

# INPUT: standard TUIO source
in.tuio://:3333

# FILTERING: OneEuro filter
+ filtering:/oneeuro?freq=60&merge

# CALIBRATION: my 4x4 matrix
+ calib:?merge&matrix=0.98,0,0,0.021,0,0.83,0,0.010,0,0,1,0,0,0,0,1

# NO OUTPUT, so I can reuse this into an external pipeline.

Then, you can reuse your configured input device as an atomic item in a new pipeline. As an example, let’s show the contact events using the viz: node, and at the same time use the recorder widget and forward the contacts to an other application listening for a TUIO source on the local port 3334. The command to run is the following:

boing "conf:./my-mt-table.txt + (viz: | rec: | out.tuio://127.0.0.1:3334)"

As you can see, saving pipeline configurations into files can be quite useful in different situations. Needless to say that you can also use the conf: node inside a configuration written in a file, so that it is possible to arrange items in a hierarchical structure.