ShowPlay Reference Manual, Chapter 1 (Introduction): PPF
Showplay paradigm timing is controlled by a simple text file, commonly referred to as a paradigm parameter file (PPF). Each PPF has two major components: a parameter settings section and a stimulus table section. Each section is a block of text; text blocks end with a blank line.
The parameter settings section appears first and is used to specify parameters to use during the paradigm. These can be any CIGAL commands, but typically just involve setting global variable values. After the parameter section there should be a blank line, followed by the stimulus timing list, organized as a table. Each line in the table specifies a separate stimulus event. The columns specify: the stimulus file name (or text string or command), a user-defined ID code value(Eventcode), a control flag (Eventflag), the Onset and Duration in milliseconds, and screen location for visual stimuli (See Stimulus Table for details.) Stimuli can overlap in time and do not need to be listed in chronological order.
The following is an example of a simple input file that mixes graphics, pictures, text, movies, and sound stimuli. (Text following a ';' is ignored by CIGAL)
showplay 0 ; initialize new showplay task sbackcolor = "black" ; screen background color stextcolor = 'white' return ; end of parameters (must be followed by blank line) ;Stimulus ID Flg Onset(ms) Duration LocationXY "Press for faces" 1 0 0 4000 -1 -1 ; show text fix 2 0 4000 0 -1 -1 ; central '+' tones1.wav 3 0 6000 0 ; play auditory tone face1.jpg 14 1 8000 1000 -1 -1 ; show pictures (1/s) face2.pcx 14 1 -1 1000 -1 -1 ; Onset value -1 means scene1.jpg 15 1 -1 1000 -1 -1 ; onset is end of prev. stim. face5.jpg 14 1 -1 1000 -1 -1 face6.jpg 14 1 -1 1000 -1 -1 movie1.avi 16 1 -1 2000 -1 -1 ; play for 2 secs fix 2 0 -1 3000 -1 -1 erase 0 0 -1 0 tones2.wav 3 0 -1 0 ; play sound "End of task" 1 0 -1 2000 -1 -1 ; text and tone simultaneous quit 0 0 -1
A Showplay paradigm file has 4 important features.
Note: A line that starts with space characters is not considered a blank line even though it may look blank. Also, a semicolon (';') and all sebsequent characters on a line is ignored by CIGAL, so that a line that starts with a semicolon will be treated as a blank line even though it doesn't look it. (Put some blank space before the semicolon if you want to embed comments within your stimulus table.)
Stimulus file names
File names for image, sound, and movie stimuli appear as the first argument in the stimulus table. These file names are relative to the SHOWDIR directory. By default, SHOWDIR is the directory containing the PPF (Param_file) itself. Alternatively, you can explicitly specify the folder containing your stimulus files by setting the SHOWDIR string variable in the upper portion of the pardigm parameter file. When set explicitly, the SHOWDIR path is relative to your current working directory (Curdir), not the directory containing the PPF.
Paradigm parameter file names
In Showplay's documentation, paradigm parameter files are typically referred to as “PPF files” and named with a “.ppf” file suffix. The file name itself doesn't matter to CIGAL, however, so you may find it more convenient to simply name these files with the standard “.txt” file suffix. When creating PPF files just be sure that they contain plain text only, with no special formatting characters. So if you use programs like Microsoft Word or Wordpad make sure to select the no formatting option when saving your file.