Interactions

Built-in mouse events

The following built-in mouse events are supported: mouse_down, mouse_move, mouse_up and mouse_out. You can define Python callback functions that will be called whenever those mouse events occur, using the on_mouse_down, on_mouse_move, on_mouse_up and on_mouse_out methods.

Those methods take a callback function as single argument, this callback function must take two positional arguments that are the x and y pixel coordinates where the mouse was during the event.

from ipywidgets import Output

out = Output()


@out.capture()
def handle_mouse_move(x, y):
    print("Mouse move event:", x, y)


canvas.on_mouse_move(handle_mouse_move)


@out.capture()
def handle_mouse_down(x, y):
    print("Mouse down event:", x, y)


canvas.on_mouse_down(handle_mouse_down)

display(out)

Built-in touch events

The following built-in touch events are supported: touch_start, touch_end, touch_move and touch_cancel. You can define Python callback functions that will be called whenever those touch events occur, using the on_touch_start, on_touch_end, on_touch_move and on_touch_cancel methods.

Those methods take a callback function as single argument, this callback function must take one positional argument which is the list of tuples representing the (x, y) pixel coordinates where the fingers are located on the canvas.

import math

out = Output()


@out.capture()
def handle_touch_move(fingers_locations):
    # Draw circles where fingers are located
    for finger_location in fingers_locations:
        canvas.fill_arc(finger_location[0], finger_location[1], 6, 0, 2 * math.pi)


canvas.on_touch_move(handle_touch_move)
display(out)

Note

Please open an issue or a Pull Request if you want more events to be supported by ipycanvas

Keyboard events

from ipywidgets import Output

out = Output()


@out.capture()
def on_keyboard_event(key, shift_key, ctrl_key, meta_key):
    print("Keyboard event:", key, shift_key, ctrl_key, meta_key)


canvas.on_key_down(on_keyboard_event)

display(out)

ipyevents

If built-in events are not enough for your use case, you can use ipyevents which provides mouse and keyboard events.

GamePad support

If you have a GamePad, you can use the game Controller widget from ipywidgets to get events from it.