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Mouse functions

class Mouse

The Mouse class is used to collect mouse input. You generally create a Mouse object with the Mouse() factory function, as described in the section Creating a Mouse.

Example:

# Draw a 'fixation-dot mouse cursor' until a button is clicked
my_mouse = Mouse()
my_canvas = Canvas()
while True:
        button, position, timestamp = my_mouse.get_click(timeout=20)
        if button is not None:
                break
        (x,y), time = my_mouse.get_pos()
        my_canvas.clear()
        my_canvas.fixdot(x, y)
        my_canvas.show()

Things to know

Creating a Mouse

You generally create a Mouse with the Mouse() factory function:

my_mouse = Mouse()

Optionally, you can pass Response keywords to Mouse() to set the default behavior:

my_mouse = Mouse(timeout=2000)

Coordinates

  • When Uniform coordinates is set to 'yes', coordinates are relative to the center of the display. That is, (0,0) is the center. This is the default as of OpenSesame 3.0.0.
  • When Uniform coordinates is set to 'no', coordinates are relative to the top-left of the display. That is, (0,0) is the top-left. This was the default in OpenSesame 2.9.X and earlier.

Button numbers

Mouse buttons are numbered as follows:

  1. Left button
  2. Middle button
  3. Right button
  4. Scroll up
  5. Scroll down

Touch screens

When working with a touch screen, a touch is registered as button 1 (left button).

Response keywords

Functions that accept **resp_args take the following keyword arguments:

  • timeout specifies a timeout value in milliseconds, or is set to None to disable the timeout.
  • buttonlist specifies a list of buttons that are accepted, or is set to None accept all buttons.
  • visible indicates whether the mouse cursor becomes visible when a click is collected (True or False). To immediately change cursor visibility, use [mouse.show_cursor].
# Get a left or right button press with a timeout of 3000 ms
my_mouse = Mouse()
button, time = my_mouse.get_click(buttonlist=[1,3], timeout=3000)

Response keywords only affect the current operation (except when passed to [mouse.__init__][init]). To change the behavior for all subsequent operations, set the response properties directly:

# Get two left or right presses with a 5000 ms timeout
my_mouse = Mouse()
my_mouse.buttonlist = [1,3]
my_mouse.timeout = 5000
button1, time1 = my_mouse.get_click()
button2, time2 = my_mouse.get_click()

Or pass the response keywords to [mouse.__init__][init]:

# Get two left or right presses with a 5000 ms timeout
my_mouse = Mouse(buttonlist=[1,3], timeout=5000)
button1, time1 = my_mouse.get_click()
button2, time2 = my_mouse.get_click()

function Mouse.flush()

Clears all pending input, not limited to the mouse.

Example:

my_mouse = Mouse()
my_mouse.flush()
button, position, timestamp = my_mouse.get_click()

Returns:

True if a button had been clicked (i.e., if there was something to flush) and False otherwise.

  • Type: bool

function Mouse.get_click(**resp_args)

Collects a mouse click.

Example:

my_mouse = Mouse()
button, (x, y), timestamp = my_mouse.get_click(timeout=5000)
if button is None:
        print('A timeout occurred!')

Keyword dict:

  • **resp_args: Optional [response keywords] that will be used for this call to [mouse.get_click]. This does not affect subsequent operations.

Returns:

A (button, position, timestamp) tuple. The button and position are None if a timeout occurs. Position is an (x, y) tuple in screen coordinates.

  • Type: tuple

function Mouse.get_click_release(**resp_args)

New in v3.2.0

Collects a mouse-click release.

Important: This function is currently not implemented for the psycho backend.

Example:

my_mouse = Mouse()
button, (x, y), timestamp = my_mouse.get_click_release(timeout=5000)
if button is None:
        print('A timeout occurred!')

Keyword dict:

  • **resp_args: Optional [response keywords] that will be used for this call to [mouse.get_click_release]. This does not affect subsequent operations.

Returns:

A (button, position, timestamp) tuple. The button and position are None if a timeout occurs. Position is an (x, y) tuple in screen coordinates.

  • Type: tuple

function Mouse.get_pos()

Returns the current position of the cursor.

Example:

my_mouse = Mouse()
(x, y), timestamp = my_mouse.get_pos()
print('The cursor was at (%d, %d)' % (x, y))

Returns:

A (position, timestamp) tuple.

  • Type: tuple

function Mouse.get_pressed()

Returns the current state of the mouse buttons. A True value means the button is currently being pressed.

Example:

my_mouse = Mouse()
buttons = my_mouse.get_pressed()
b1, b2, b3 = buttons
print('Currently pressed mouse buttons: (%d,%d,%d)' % (b1,b2,b3))

Returns:

A (button1, button2, button3) tuple of boolean values.

  • Type: tuple.

function Mouse.set_pos(pos=(0, 0))

Sets the position of the mouse cursor.

Warning: set_pos() is unreliable and will silently fail on some systems.

Example:

my_mouse = Mouse()
my_mouse.set_pos(pos=(0,0))

Keywords:

  • pos -- An (x,y) tuple for the new mouse coordinates.
    • Type: tuple
    • Default: (0, 0)

function Mouse.show_cursor(show=True)

Immediately changes the visibility of the mouse cursor.

Note: In most cases, you will want to use the visible [keyword][Response keywords], which changes the visibility during response collection, that is, while mouse.get_click() is called.

Keywords:

  • show -- Indicates whether the cursor is shown (True) or hidden (False).
    • Type: bool
    • Default: True
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