jsPsych/plugins/jspsych-animation.js
2015-12-17 13:57:53 -05:00

124 lines
3.4 KiB
JavaScript

/**
* jsPsych plugin for showing animations and recording keyboard responses
* Josh de Leeuw
*
* documentation: docs.jspsych.org
*/
jsPsych.animation = (function() {
var plugin = {};
jsPsych.pluginAPI.registerPreload('animation', 'stimuli', 'image');
plugin.trial = function(display_element, trial) {
trial.frame_time = trial.frame_time || 250;
trial.frame_isi = trial.frame_isi || 0;
trial.sequence_reps = trial.sequence_reps || 1;
trial.choices = trial.choices || [];
trial.prompt = (typeof trial.prompt === 'undefined') ? "" : trial.prompt;
// if any trial variables are functions
// this evaluates the function and replaces
// it with the output of the function
trial = jsPsych.pluginAPI.evaluateFunctionParameters(trial);
var interval_time = trial.frame_time + trial.frame_isi;
var animate_frame = -1;
var reps = 0;
var startTime = (new Date()).getTime();
var animation_sequence = [];
var responses = [];
var current_stim = "";
var animate_interval = setInterval(function() {
var showImage = true;
display_element.html(""); // clear everything
animate_frame++;
if (animate_frame == trial.stimuli.length) {
animate_frame = 0;
reps++;
if (reps >= trial.sequence_reps) {
endTrial();
clearInterval(animate_interval);
showImage = false;
}
}
if (showImage) {
show_next_frame();
}
}, interval_time);
function show_next_frame() {
// show image
display_element.append($('<img>', {
"src": trial.stimuli[animate_frame],
"id": 'jspsych-animation-image'
}));
current_stim = trial.stimuli[animate_frame];
// record when image was shown
animation_sequence.push({
"stimulus": current_stim,
"time": (new Date()).getTime() - startTime
});
if (trial.prompt !== "") {
display_element.append(trial.prompt);
}
if (trial.frame_isi > 0) {
setTimeout(function() {
$('#jspsych-animation-image').css('visibility', 'hidden');
current_stim = 'blank';
// record when blank image was shown
animation_sequence.push({
"stimulus": 'blank',
"time": (new Date()).getTime() - startTime
});
}, trial.frame_time);
}
}
var after_response = function(info) {
responses.push({
key_press: info.key,
rt: info.rt,
stimulus: current_stim
});
// after a valid response, the stimulus will have the CSS class 'responded'
// which can be used to provide visual feedback that a response was recorded
$("#jspsych-animation-image").addClass('responded');
}
// hold the jspsych response listener object in memory
// so that we can turn off the response collection when
// the trial ends
var response_listener = jsPsych.pluginAPI.getKeyboardResponse({
callback_function: after_response,
valid_responses: trial.choices,
rt_method: 'date',
persist: true,
allow_held_key: false
});
function endTrial() {
jsPsych.pluginAPI.cancelKeyboardResponse(response_listener);
var trial_data = {
"animation_sequence": JSON.stringify(animation_sequence),
"responses": JSON.stringify(responses)
};
jsPsych.finishTrial(trial_data);
}
};
return plugin;
})();