jsPsych/plugins/jspsych-image-button-response.js

314 lines
12 KiB
JavaScript

/**
* jspsych-image-button-response
* Josh de Leeuw
*
* plugin for displaying a stimulus and getting a button response
*
* documentation: docs.jspsych.org
*
**/
jsPsych.plugins["image-button-response"] = (function() {
var plugin = {};
jsPsych.pluginAPI.registerPreload('image-button-response', 'stimulus', 'image');
plugin.info = {
name: 'image-button-response',
description: '',
parameters: {
stimulus: {
type: jsPsych.plugins.parameterType.IMAGE,
pretty_name: 'Stimulus',
default: undefined,
description: 'The image to be displayed'
},
stimulus_height: {
type: jsPsych.plugins.parameterType.INT,
pretty_name: 'Image height',
default: null,
description: 'Set the image height in pixels'
},
stimulus_width: {
type: jsPsych.plugins.parameterType.INT,
pretty_name: 'Image width',
default: null,
description: 'Set the image width in pixels'
},
maintain_aspect_ratio: {
type: jsPsych.plugins.parameterType.BOOL,
pretty_name: 'Maintain aspect ratio',
default: true,
description: 'Maintain the aspect ratio after setting width or height'
},
choices: {
type: jsPsych.plugins.parameterType.STRING,
pretty_name: 'Choices',
default: undefined,
array: true,
description: 'The labels for the buttons.'
},
button_html: {
type: jsPsych.plugins.parameterType.STRING,
pretty_name: 'Button HTML',
default: '<button class="jspsych-btn">%choice%</button>',
array: true,
description: 'The html of the button. Can create own style.'
},
prompt: {
type: jsPsych.plugins.parameterType.STRING,
pretty_name: 'Prompt',
default: null,
description: 'Any content here will be displayed under the button.'
},
stimulus_duration: {
type: jsPsych.plugins.parameterType.INT,
pretty_name: 'Stimulus duration',
default: null,
description: 'How long to hide the stimulus.'
},
trial_duration: {
type: jsPsych.plugins.parameterType.INT,
pretty_name: 'Trial duration',
default: null,
description: 'How long to show the trial.'
},
margin_vertical: {
type: jsPsych.plugins.parameterType.STRING,
pretty_name: 'Margin vertical',
default: '0px',
description: 'The vertical margin of the button.'
},
margin_horizontal: {
type: jsPsych.plugins.parameterType.STRING,
pretty_name: 'Margin horizontal',
default: '8px',
description: 'The horizontal margin of the button.'
},
response_ends_trial: {
type: jsPsych.plugins.parameterType.BOOL,
pretty_name: 'Response ends trial',
default: true,
description: 'If true, then trial will end when user responds.'
},
render_on_canvas: {
type: jsPsych.plugins.parameterType.BOOL,
pretty_name: 'Render on canvas',
default: true,
description: 'If true, the image will be drawn onto a canvas element (prevents blank screen between consecutive images in some browsers).'+
'If false, the image will be shown via an img element.'
}
}
}
plugin.trial = function(display_element, trial) {
var height, width;
var html;
if (trial.render_on_canvas) {
// first clear the display element (because the render_on_canvas method appends to display_element instead of overwriting it with .innerHTML)
if (display_element.hasChildNodes()) {
// can't loop through child list because the list will be modified by .removeChild()
while (display_element.firstChild) {
display_element.removeChild(display_element.firstChild);
}
}
// create canvas element and image
var canvas = document.createElement("canvas");
canvas.id = "jspsych-image-button-response-stimulus";
canvas.style.margin = 0;
canvas.style.padding = 0;
var img = new Image();
img.src = trial.stimulus;
// determine image height and width
if (trial.stimulus_height !== null) {
height = trial.stimulus_height;
if (trial.stimulus_width == null && trial.maintain_aspect_ratio) {
width = img.naturalWidth * (trial.stimulus_height/img.naturalHeight);
}
} else {
height = img.naturalHeight;
}
if (trial.stimulus_width !== null) {
width = trial.stimulus_width;
if (trial.stimulus_height == null && trial.maintain_aspect_ratio) {
height = img.naturalHeight * (trial.stimulus_width/img.naturalWidth);
}
} else if (!(trial.stimulus_height !== null & trial.maintain_aspect_ratio)) {
// if stimulus width is null, only use the image's natural width if the width value wasn't set
// in the if statement above, based on a specified height and maintain_aspect_ratio = true
width = img.naturalWidth;
}
canvas.height = height;
canvas.width = width;
// create buttons
var buttons = [];
if (Array.isArray(trial.button_html)) {
if (trial.button_html.length == trial.choices.length) {
buttons = trial.button_html;
} else {
console.error('Error in image-button-response plugin. The length of the button_html array does not equal the length of the choices array');
}
} else {
for (var i = 0; i < trial.choices.length; i++) {
buttons.push(trial.button_html);
}
}
var btngroup_div = document.createElement('div');
btngroup_div.id = "jspsych-image-button-response-btngroup";
html = '';
for (var i = 0; i < trial.choices.length; i++) {
var str = buttons[i].replace(/%choice%/g, trial.choices[i]);
html += '<div class="jspsych-image-button-response-button" style="display: inline-block; margin:'+trial.margin_vertical+' '+trial.margin_horizontal+'" id="jspsych-image-button-response-button-' + i +'" data-choice="'+i+'">'+str+'</div>';
}
btngroup_div.innerHTML = html;
// add canvas to screen and draw image
display_element.insertBefore(canvas, null);
var ctx = canvas.getContext("2d");
ctx.drawImage(img,0,0,width,height);
// add buttons to screen
display_element.insertBefore(btngroup_div, canvas.nextElementSibling);
// add prompt if there is one
if (trial.prompt !== null) {
var prompt_div = document.createElement("div");
prompt_div.innerHTML = trial.prompt;
display_element.insertBefore(prompt_div, btngroup_div.nextElementSibling);
}
} else {
// display stimulus as an image element
html = '<img src="'+trial.stimulus+'" id="jspsych-image-button-response-stimulus">';
//display buttons
var buttons = [];
if (Array.isArray(trial.button_html)) {
if (trial.button_html.length == trial.choices.length) {
buttons = trial.button_html;
} else {
console.error('Error in image-button-response plugin. The length of the button_html array does not equal the length of the choices array');
}
} else {
for (var i = 0; i < trial.choices.length; i++) {
buttons.push(trial.button_html);
}
}
html += '<div id="jspsych-image-button-response-btngroup">';
for (var i = 0; i < trial.choices.length; i++) {
var str = buttons[i].replace(/%choice%/g, trial.choices[i]);
html += '<div class="jspsych-image-button-response-button" style="display: inline-block; margin:'+trial.margin_vertical+' '+trial.margin_horizontal+'" id="jspsych-image-button-response-button-' + i +'" data-choice="'+i+'">'+str+'</div>';
}
html += '</div>';
// add prompt
if (trial.prompt !== null){
html += '<div>'+trial.prompt+'</div>';
}
// update the page content
display_element.innerHTML = html;
// set image dimensions after image has loaded (so that we have access to naturalHeight/naturalWidth)
var img = display_element.querySelector('#jspsych-image-button-response-stimulus');
if (trial.stimulus_height !== null) {
height = trial.stimulus_height;
if (trial.stimulus_width == null && trial.maintain_aspect_ratio) {
width = img.naturalWidth * (trial.stimulus_height/img.naturalHeight);
}
} else {
height = img.naturalHeight;
}
if (trial.stimulus_width !== null) {
width = trial.stimulus_width;
if (trial.stimulus_height == null && trial.maintain_aspect_ratio) {
height = img.naturalHeight * (trial.stimulus_width/img.naturalWidth);
}
} else if (!(trial.stimulus_height !== null & trial.maintain_aspect_ratio)) {
// if stimulus width is null, only use the image's natural width if the width value wasn't set
// in the if statement above, based on a specified height and maintain_aspect_ratio = true
width = img.naturalWidth;
}
img.style.height = height.toString() + "px";
img.style.width = width.toString() + "px";
}
// start timing
var start_time = performance.now();
for (var i = 0; i < trial.choices.length; i++) {
display_element.querySelector('#jspsych-image-button-response-button-' + i).addEventListener('click', function(e){
var choice = e.currentTarget.getAttribute('data-choice'); // don't use dataset for jsdom compatibility
after_response(choice);
});
}
// store response
var response = {
rt: null,
button: null
};
// function to handle responses by the subject
function after_response(choice) {
// measure rt
var end_time = performance.now();
var rt = end_time - start_time;
response.button = parseInt(choice);
response.rt = rt;
// 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
display_element.querySelector('#jspsych-image-button-response-stimulus').className += ' responded';
// disable all the buttons after a response
var btns = document.querySelectorAll('.jspsych-image-button-response-button button');
for(var i=0; i<btns.length; i++){
//btns[i].removeEventListener('click');
btns[i].setAttribute('disabled', 'disabled');
}
if (trial.response_ends_trial) {
end_trial();
}
};
// function to end trial when it is time
function end_trial() {
// kill any remaining setTimeout handlers
jsPsych.pluginAPI.clearAllTimeouts();
// gather the data to store for the trial
var trial_data = {
"rt": response.rt,
"stimulus": trial.stimulus,
"button_pressed": response.button
};
// clear the display
display_element.innerHTML = '';
// move on to the next trial
jsPsych.finishTrial(trial_data);
};
// hide image if timing is set
if (trial.stimulus_duration !== null) {
jsPsych.pluginAPI.setTimeout(function() {
display_element.querySelector('#jspsych-image-button-response-stimulus').style.visibility = 'hidden';
}, trial.stimulus_duration);
}
// end trial if time limit is set
if (trial.trial_duration !== null) {
jsPsych.pluginAPI.setTimeout(function() {
end_trial();
}, trial.trial_duration);
} else if (trial.response_ends_trial === false) {
console.warn("The experiment may be deadlocked. Try setting a trial duration or set response_ends_trial to true.");
}
};
return plugin;
})();