Youtube element

Youtube elements let you add youtube videos to the page using their reference code (what comes after watch?v= in the video’s URL):

Creation:

newYoutube("myVideo", "aFPtc8BVdJk")

PennController is set to preload all resources, which means the trial will not start until the youtube video is stored in the browser’s cache.

Note that Youtube elements use Youtube’s IFrame player API. Support might vary across browsers (e.g., preloading seems more efficient on Firefox than on Chrome).

By default, the Youtube controls of the videos (buttons, progress bar, …) are not displayed. You can tell PennController to show the controls by adding a third parameter upon creation:

newYoutube("myVideo", "aFPtc8BVdJk", "show controls")

This setting cannot be changed by a command as of beta 0.3.

Actions

youtube.pause

getYoutube(id).pause()

Pauses the video.

Example:

newYoutube("mcgurk", "aFPtc8BVdJk")
    .print()
    .play()
,
newTimer("preview", 1000)
    .start()
    .wait()
,
getYoutube("mcgurk")
    .pause()

Starts playing a mind-blowing video demonstrating the McGurk effect, waits 1 second and pauses the video.

youtube.play

getYoutube(id).play()

Starts playing the video. If you did not use print before, the video will not be visible on the screen but sound will start playing anyway.

Example:

newYoutube("mcgurk", "aFPtc8BVdJk")
    .print()
    .play()
    .wait()

Plays a mind-blowing video demonstrating the McGurk effect.

youtube.stop

getYoutube(id).stop() (since beta 0.3)

Pauses the video and moves it back to the beginning (position = 0s).

Example:

newYoutube("mcgurk", "aFPtc8BVdJk")
    .print()
    .play()
,
newTimer("preview", 2000)
    .start()
    .wait()
,
getYoutube("mcgurk")
    .stop()

Starts playing a mind-blowing video demonstrating the McGurk effect, waits 2 seconds and stops the video. The video will start over from the beginning next time it is played.

youtube.wait

getYoutube(id).wait()

or getYoutube(id).wait("first")

or getYoutube(id).wait( test )

Waits until the video has ended before evaluating and executing the next commands.

If you call wait("first"), then if the video has already been fully played at least once by the time this command is evaluated, the next commands are evaluated and executed right away. If it was never fully played before, the next commands are only evaluated and executed after the audio has been played.

If you pass a test on an element as an argument, it only evaluates and executes the next commands when the video finishes playing while the test is successful. If the test is not successful, it will be checked again next time the video ends.

Example:

newYoutube("mcgurk", "aFPtc8BVdJk")
    .print()
    .play()
,
newButton("validation", "Validate")
    .print()
    .wait()
,
getYoutube("mcgurk")
    .wait("first")
,
newButton("thanks", "Thank you for watching")
    .print()
    .wait()

Starts playing a mind-blowing video demonstrating the McGurk effect and adds a button onto the screen. If the button is clicked before the video has ended for the first time, it waits until the end before printing a button saying Thank you for watching.

standard.print

getElement(id).print()

or getElement(id).print(x,y) (limited support in PennController 1.3, general since 1.4)

or getElement(id).print(x,y,canvas) (limited support in PennController 1.3, general since 1.4)

Adds the content of the element to the screen. This has no effect for non-visual elements such as the purely interactive Selector elements.

Since PennController 1.3, you can pass x and y values to print the element at a specific position on the page, or on a Canvas element if you pass one (or the name of a Canvas element) as the third parameter. You can use any CSS coordinate format for x and y, or special string values following the respective formats "left|center|right at ..." and "top|middle|bottom at ...". Note that x and y are not supported for Audio, Canvas, Scale, TextInput, Video and Youtube elements in PennController 1.3 ; note also that elements added with .settings.before and .settings.after mess with proportional coordinates.

standard.refresh

getElement(id).refresh() (since PennController 1.1)

Calls the command print again on the element, while leaving it where it was printed last.

This command is primarily useful if some aesthetic command does not take effect unless print is called afterward, but you do not want to call print because calling it when you need the aesthetic command to take effect would move the element undesirably.

NOTE: PennController 1.1 handles this command incorrectly and it bugs systematically (draft)

Example:

newImage( "smiley" , "ya.png" )
,
newCanvas( "myCanvas" , 100 , 100 )
    .settings.css( "border" , "solid 1px black" )
    .settings.center()
    .settings.add( "center at 50%" , "center at 50%" , getImage("smiley") )
    .print()
,
newButton( "resize" , "Resize the image" )
    .print()
    .wait()
,
getImage( "smiley" )
    .settings.size( 64, 64 )
,
getCanvas("myCanvas")
    .refresh()

Prints the smiley image at the center of the canvas and adds a button below the canvas. After the button is clicked, the smiley is resized to 64×64 and without refresh the smiley would no longer be centrally aligned on canvas. Calling print on the canvas would recenter the image correctly, but it would move the canvas below the button. The solution is therefore to call refresh (or to call the settings command add again on the canvas).

standard.remove

getElement(id).remove()

Removes the element from the screen. This has no effect for non-visual elements such as the purely interactive Selector elements.

Note that this leaves no space where the element previously was on the page (this is really removing the element, not just hiding it).

Example

newButton("clickme", "Click me")
    .print()
    .wait()
    .remove()

Adds a button that says Click me to the screen, and removes it after it is clicked.

standard.setVar

getElement(id).setVar( varName ) (since beta 0.3)

Stores the current value of the element in the Var element named varName (if it exists).

What the current value corresponds to is specific to each element type:

  • For Audio elements, it corresponds to the timestamp of the end of the last playback so far (0 if never played back or playback never eneded).
  • For Button elements, it corresponds to the timestamp of the last click so far (0 if never clicked).
  • For Canvas elements, it corresponds to the number of elements it currently contains.
  • For Function elements, it corresponds to the value returned by the function.
  • For Html elements, it corresponds to whether the element is completely filled.
  • For Image elements, it corresponds to whether the image is currently being displayed.
  • For Key elements, it corresponds to the last key that was pressed so far (empty string if no key has been pressed so far).
  • For Scale elements, it corresponds to the value of the last option that was selected (NaN if no option has been selected so far).
  • For Selector elements, it corresponds to the last element that was selected (null if no element has been selected so far).
  • For Text elements, it corresponds to the current text.
  • For TextInput elements, it corresponds to the text that is currently in the input box.
  • For Timer elements, it corresponds to whether the timer has elapsed.
  • For Tooltip elements, it corresponds to whether the tooltip has been validated.
  • For Var elements, it corresponds to the element’s value.
  • For Video elements, it corresponds to the timestamp of the end of the last playback so far (0 if never played back or playback never eneded).
  • For VoiceRecorder elements, it corresponds to the last recording (undefined if no recording so far).
  • For Youtube elements, it corresponds to whether the video has been played.

Example:

newVar("name")
,
newTextInput("nameInput", "What is your name?")
    .settings.once()
    .print()
    .wait()
    .setVar("name")
,
newText("helloname")
    .settings.before( newText("hello", "Hello ") )
    .settings.text( getVar("name") )
    .print()

Creates a Var element named name and adds a text box in which to enter a name. When the return/enter key is pressed while editing the input box, it disables the box and stores its value in the Var element named name. Then it prints a text reading Hello name, where name corresponds to the value of the Var element.

Settings

youtube.settings.log

log

getYoutube(id).settings.log() (since beta 0.3)

or getYoutube(id).settings.log("play") (since beta 0.4)

or getYoutube(id).settings.log("end") (since beta 0.4)

or getYoutube(id).settings.log("pause") (since beta 0.4)

or getYoutube(id).settings.log("buffer") (since beta 0.4)

or getYoutube(id).settings.log("play", "buffer", ...) (since beta 0.4)

or getYoutube(id).settings.log("all") (since beta 0.3)

Note: since beta 0.4, blank parentheses default back "play". In beta 0.3, they default back to "all".

Will add a line for the following events in the results file, regardless of whether they result from a click/key press or from a script command.

  • The video starts playing
  • The video pauses
  • The video ends
  • The video is buffering (i.e. loading before it can play or continue playing)

Each line will report the timestamp of the event, as well as the position (in seconds) of the video at the moment of the event. Given the asynchronous mechanism behind the Youtube API, there may be delays: for instance the position of an initial play event may not be 0, and you should subtract it from the reported timestamp to get an accurate measure of when the video really started playing.

Example:

newYoutube("myYoutube", "code")
    .settings.log("play", "buffer")
    .play()
    .wait()

Will start playing a Youtube video without showing it. Each play and each buffer event will add a line to the results file.

youtube.settings.once

getYoutube(id).settings.once() (since beta 0.3)

Will disable the Youtube video after it has finished playing.

Example:

newYoutube("myYoutube", "aFPtc8BVdJk")
    .settings.once()
    .print()
    .play()
    .wait()
,
newButton("validate", "Validate")
   .print()
   .wait()

Shows a video on the page and starts playing it. Playback will become disabled after it has finished.

standard.settings.after

getElement(id).settings.after( getElement(id) )

Adds some content to the right of the element.

Example:

newImage("bad", "no.png")
,
newImage("good", "ya.png")
,
newText("left label", "Bad")
    .settings.before( getImage("bad") )
,
newText("right label", "Good")
    .settings.after( getImage("good") )
,
newScale("judgment", 5)
    .settings.before( getText("left label") )
    .settings.after( getText("right label") )
    .print()
    .wait()

Creates two image and two text elements and prints a 5-point radio-button scale, with the text Bad preceded by the image no.png on its left, and the text Good followed by the image ya.png on its right.

standard.settings.before

or getElement(id).settings.before( getElement(id) )

Adds some content to the left of the element.

Example:

newImage("bad", "no.png")
,
newImage("good", "ya.png")
,
newText("left label", "Bad")
    .settings.before( getImage("bad") )
,
newText("right label", "Good")
    .settings.after( getImage("good") )
,
newScale("judgment", 5)
    .settings.before( getText("left label") )
    .settings.after( getText("right label") )
    .print()
    .wait()

Creates two image and two text elements and prints a 5-point radio-button scale, with the text Bad preceded by the image no.png on its left, and the text Good followed by the image ya.png on its right.

standard.settings.center

getElement(id).settings.center()

Makes the element appear centered on the horizontal axis.

Example:

newText("helloworld", "Hello world")
    .settings.center()
    .print()

Prints Hello world onto the screen, horizontally centered.

standard.settings.css

getElement(id).settings.css("styleName", "style")

or getElement(id).settings.css({"style name 1": "style 1", "style name 2": "style 2"})

Applies the CSS style(s) to the element.

Example:

newText("frame", "framed")
    .settings.css("border", "solid 1px black")
,
newText("sentence", "The last word of this sentence is ")
    .settings.after( getText("frame") )
    .print()

Prints a text reading The last word of this sentence is framed, with the last word (framed) framed in a box with 1px black borders.

standard.settings.disable

getElement(id).settings.disable()

Disables any interactive feature of the element.

Note: this does not prevent an element that is part of a Selector element from being selected.

Example:

newAudio("sentence", "test.mp3")
    .print()
    .wait()
,
getAudio("sentence")
    .settings.disable()

Prints buttons to play/pause the audio file test_sentence.ogg, and disables those buttons when the file has played through.

standard.settings.enable

getElement(id).settings.enable()

Enables any interactive feature of the element that was previously disabled.

Example:

newAudio("sentence", "test.mp3")
    .settings.once()
    .print()
,
newKey("secret key", "R")
    .wait()
,
getAudio("sentence")
    .settings.enable()

Prints buttons to play/pause the audio file test_sentence.ogg, and disables those buttons when the file has played through (see audio.settings.once).

standard.settings.hidden

getElement(id).settings.hidden() (since beta 0.3)

Makes the element invisible. Note that when printed, a hidden element still occupies space on the page, but its content is not visible.

Example:

newText("instruction", "Guess what fruit is in the image below")
    .print()
,
newImage("fruit", "pear.png")
    .settings.hidden()
    .print()
,
newButton("reveal", "Reveal fruit")
    .print()
    .wait()
,
getImage("fruit")
    .settings.visible()

Adds some text to the page, a blank space below it and a button below the blank space which, when clicked, reveals an image of a pear.

standard.settings.left

getElement(id).settings.left()

Makes the element appear horizontally aligned to the left (default).

Note: the left means the left of the container of the element, not necessarily the left of the screen.

Example:

newText("helloworld", "Hello world")
    .settings.right()
    .print()
,
newButton("left", "Align text to the left")
    .print()
    .wait()
,
getText("helloworld")
    .settings.left()

Prints Hello world onto the screen, horizontally aligned to the left.

standard.settings.right

getElement(id).settings.right()

Makes the element appear horizontally aligned to the right.

Note: the right means the right of the container of the element, not necessarily the right of the screen.

Example:

newText("sentence", "This is a longer sentence")
    .print()
,
newText("helloworld", "Hello world")
    .settings.right()
    .print()

Prints Hello world onto the screen, horizontally aligned to the right.

standard.settings.selector

getElement(id).settings.selector( selectorName )

or getElement(id).settings.selector( getSelector(selectorName) ) (since beta 0.3)

Since beta 0.3, Selector adds a .settings.selector command to all elements as another method for adding them to a selector.

Example:

newSelector("shapes")
,
newImage("square", "square.png")
    .settings.selector("shapes")
,
newImage("triangle", "triangle.png")
    .settings.selector("shapes")
,
newCanvas("shapes canvas", 825, 400)
    .settings.add(  0, 0, getImage("square") )
    .settings.add(425, 0, getImage("triangle") )
    .print()
,
getSelector("shapes")
    .wait()

Adds two images side by side and waits for a click on either one of them.

standard.settings.size

getElement(id).settings.size(width, height)

Resizes the element to a width of width pixels and a height of height pixels.

Example:

newImage("smiley", "pear.png")
    .settings.size(40, 40)
    .print()

Adds a 40x40px image pear.png onto the screen.

standard.settings.visible

getElement(id).settings.visible() (since beta 0.3)

Makes the element visible (again). This is useful if you previously hid the element with .settings.hidden.

Example:

newText("instruction", "Guess what fruit is in the image below")
    .print()
,
newImage("fruit", "pear.png")
    .settings.hidden()
    .print()
,
newButton("reveal", "Reveal fruit")
    .print()
    .wait()
,
getImage("fruit")
    .settings.visible()

Adds some text to the page, a blank space below it and a button below the blank space which, when clicked, reveals an image of a pear.

Tests

youtube.test.hasPlayed

getYoutube(id).test.hasPlayed() (since beta 0.3)

Tests whether the end of the video was reached at least once. Note that the video need not have fully played, if the position was manually set before reaching the end.

youtube.test.playing

getYoutube(id).test.playing() (since beta 0.3)

Tests whether the video is currently playing.

standard.test.printed

getElement(id).test.printed() (since beta 0.3)

Tests whether the element was printed onto the page (and has not been removed since then).

Example:

newText("instructions", "Click on Top/Bottom to NOT print its word")
    .print()
,
newButton("top", "Top")
    .settings.callback( getButton("top").remove() ) 
    .print()
,
newButton("bottom", "Bottom")
    .settings.callback( getButton("bottom").remove() )
    .print()
,
newButton("print", "Print the buttons' words")
    .print()
    .wait()
    .remove()
,
getButton("top")
    .test.printed()
    .success( newText("top word", "hello").print() )
,
getButton("bottom")
    .test.printed()
    .success( newText("bottom word", "world").print() )

Prints a Top and a Bottom button onto the page, which disappear when clicked. After a click on the print button, the word hello will appear if the top button is still displayed, and the word world will appear if the bottom button is still displayed.