2.3.5.8 Multiframe Picture Response (%L)

The Multiframe Picture Response command allows the user to show a series of loaded pictures in succession. The pictures can come from any of the Cogsys picture loading/creating commands: Load Picture List, Load Referenced Pictures, or Create Pictures by CXR.

Multiframe Picture Response takes a sequence of triplets to specify the start picture, end picture and frames per picture that each image is to be displayed for. It then displays the pictures, continuously checking for keypress. If the subject hasn't pressed a key when it has finished displaying the last picture, it continues to wait for key press. Whenever the subject makes a response, the key and time are written to output.

Multiframe Picutre Response can also optionally take a zero frame number, which species which frame to start counting after. Important: if the subject makes a response before the zero frame, the response time written will be a negative number.

Multiframe Picture Response will terminate Cogsys execution of the experiment if the (BREAKOUT_CHAR) key is entered.

Multiframe displays are synchronized to the monitor's raster beam, which ensures that an image is displayed for exactly the number of frames that the user specifies.

If a testlist uses any of the multiframe picture commands (Multiframe Picture Display %J, Response Multiframe Cycling Picture Display %K, or Multiframe Picture Response %L), Cogsys empirically measures the frame rate and appends lines to the output explicitly stating the refresh rate and frame speed for this experiment.

Name:

Multiframe Picture Response

Class:

Pictures

Code:

%L

Syntax:

%L[ [Zzeroframe,] start,end,frames [, start2, end2, frames2] ... ]
start and end are integers from 1 to (MAX_UNIQUE_PICS - 1)
fames is an integer from 1 to MAX_FRAMES (
zeroframe is an integer from 1 to (MAX_UNIQUE_PICS). No more than (MAX_PICSETS) triplets can be specified.

System:

Displays the pictures from start to end for frame frames each, repeat for each set of pictures. Checks for keypress throughout display; if none, waits for keypress at end. Writes key and time to output, adjusting timer to start after frame zeroimage was displayed.

Output:

The key pressed and time are written to output.

Requires:

Cogsys must be in a graphics mode, and the referenced pictures must be loaded.

Breakout:

YES

Test Files:

`MFPR_T01.IN'

tests basic operation

Examples:

input

%L[Z12,1,1,12,2,5,2]

cogsys

Starts to display picture 1 for 12 frames, followed by pictures 2 through 5 for 2 frames each.

subject

Press z 25 milliseconds after picture 2 begins to appear.

cogsys

Terminates the command. Once a key is pressed, the loop is ended, even if it hasn't completed yet.

output

z25