PythonObject

Introduction

Accepts NoteProcessors: yes

Allows for using of the Python programming language to generate score data, using the Jython interpreter to interpret Python scripts. You may add your own python classes to the library for use with "import" statements by adding them to your BLUE_HOME/pythonLib folder. Included with Blue is Maurizio Umberto Puxeddu's pmask, as well as Steven Yi's Orchestral Composition library, found in Blue's application directory under blue/pythonLib.

After writing your script to generate notes, assign the string value of the notes to the variable 'score'. Blue will then read in the value from that variable and continue processing.

Example

temp = ""

for i in range(4):
  temp += "i1 %d 1 %s %s\n"%(i, "8.0" + str(i), 80)

score = temp

The above example script will generate four notes at ascending half steps. If the PythonObject is set with a start time of 0 and a duration of 2, then it will generate the following score:

i1  0.0 0.5 8.00    80
i1  0.5 0.5 8.01    80
i1  1.0 0.5 8.02    80
i1  1.5 0.5 8.03    80

Regarding Processing

Blue processes soundObjects by going through each SoundLayer and generating score for each object within each layer. This is useful to know so that if you are using a PythonObject that has utility functions that you later use in other PythonObjects, you should put that utility PythonObject on the first SoundLayer closest to the top, or at least on a layer above all others that contain PythonObjects.

Also to note, as a feature, Blue uses a single interpreter instance for processing python code. Therefore, if one PythonObject has code evaluated, the values from that code can be read by other objects. This allows creating utility PythonObjects. However, one can use stale values (or values from another project even) if one is not careful to always assign values in the project that require being set for this particular project.

Variables from Blue

The following variables are avaialable from Blue:

blueDuration

Duration of the Python SoundObject

blueProjectDir

The location of the current project's directory. Includes path separator at end.

Process at Start

There is a checkbox entitled "Process at Start". Selecting this option will have the script of the PythonObject run when a .blue project is loaded. This is useful for scripts that act as library functions, but themselves do not generate any notes. For example, you might define a number of score generation utility functions in one PythonObject that has "Process at Start" enabled. Your other PythonObjects may then use the functions from that PythonObject. Next time you load your project, if that PythonObject hasn't been run, your other PythonObjects will not be able to be run either. If you are rendering from the beginning of a project, this won't be an issue, but if you're starting work in the middle of a project, you will need to evaluate that utility PythonObject at least once. You can either do a run from the start at least once, use the "Test" button to have that evaluated, or use "Process at Start" and have Blue ensure it is loaded into the python interpreter when you load your projects.

An introduction video on the PythonObject can be found here.