Keyboard

class quanser.devices.interfaces.Keyboard

A Python wrapper for the Quanser Devices API interface for the keyboard.

Example

>>> from quanser.devices import Keyboard
>>> keyboard = Keyboard()

createBuffer(num_keys)

Creates a buffer for the keyboard states.

Parameters: num_keys (int) – The maxiumum number of key states that will be stored in the buffer.
Return type: Returns a buffer for keyboard states supporting the requested number of keys.

Example

Print the state of the Enter, Shift, Ctrl and A keys. Exit the loop if Ctrl+Shift+Enter pressed simultaneously.

>>> from quanser.devices import Keyboard, VirtualKeyCodes
>>> import array as arr
>>>
>>> keyboard = Keyboard()
>>>
>>> keys = arr.array('i', [VirtualKeyCodes.VK_RETURN, VirtualKeyCodes.VK_SHIFT, VirtualKeyCodes.VK_CONTROL, VirtualKeyCodes.VK_A])
>>> states = keyboard.createBuffer(len(keys))
>>>
>>> while True:
>>>     keyboard.getKeyStates(keys, states)
>>>     print(f"Return: {states[0]:x} Shift: {states[1]:x} Ctrl: {states[2]:x} A: {states[3]:x}")
>>>     if states[0] & KeyState.KEY_DOWN and states[1] & KeyState.KEY_DOWN and states[2] & KeyState.KEY_DOWN: # Press Ctrl+Shift+Enter to exit loop
>>>         break

getKeyState(virtual_key_code)

Gets the state of the given key.

Parameters: virtual_key_code (int) – A virtual key code indicating the key whose state is being retrieved. Use the VirtualKeyCodes class to use a symbolic name for the virtual key code.
Return type: Returns the state of the key. Use the KeyState class to compare values with symbolic names.

Example

Exit a loop when the Esc key is pressed.

>>> from quanser.devices import Keyboard, KeyState, VirtualKeyCodes
>>>
>>> keyboard = Keyboard()
>>>
>>> while True:
>>>     state = keyboard.getKeyState(VirtualKeyCodes.VK_ESCAPE)
>>>     print(f"Escape: {state:x}")
>>>     if state & KeyState.KEY_DOWN: # Press Esc to exit loop
>>>         break

getKeyStates(virtual_key_codes, states)

Gets the state of the given keys.

Parameters

virtual_key_codes (int[]) – An array of virtual key codes indicating the keys whose states are being retrieved. Use the VirtualKeyCodes class to use symbolic names for virtual key codes.
states (t_key_state[]) – A buffer created using the createBuffer() method that will be filled with the state of each corresponding key in the virtual_key_codes array. The buffer must be at least as large as the virtual_key_codes array. It should only be created once and then used multiple times for best performance. Use the KeyState class to compare values with symbolic names.

Examples

Print the state of the Enter, Shift, Ctrl and A keys. Exit the loop if Ctrl+Shift+Enter pressed simultaneously. Use array for the virtual key codes.

>>> from quanser.devices import Keyboard, KeyState, VirtualKeyCodes
>>> import array as arr
>>>
>>> keyboard = Keyboard()
>>>
>>> keys = arr.array('l', [VirtualKeyCodes.VK_RETURN, VirtualKeyCodes.VK_SHIFT, VirtualKeyCodes.VK_CONTROL, VirtualKeyCodes.VK_A])
>>> states = keyboard.createBuffer(len(keys))
>>>
>>> while True:
>>>     keyboard.getKeyStates(keys, states)
>>>     print(f"Return: {states[0]:x} Shift: {states[1]:x} Ctrl: {states[2]:x} A: {states[3]:x}")
>>>     if states[0] & KeyState.KEY_DOWN and states[1] & KeyState.KEY_DOWN and states[2] & KeyState.KEY_DOWN: # Press Ctrl+Shift+Enter to exit loop
>>>         break

Print the state of the Enter, Shift, Ctrl and A keys. Exit the loop if Ctrl+Shift+Enter pressed simultaneously. Use numpy array for the virtual key codes.

>>> from quanser.devices import Keyboard, KeyState, VirtualKeyCodes
>>> import numpy as np
>>>
>>> keyboard = Keyboard()
>>>
>>> keys = np.array([VirtualKeyCodes.VK_RETURN, VirtualKeyCodes.VK_SHIFT, VirtualKeyCodes.VK_CONTROL, VirtualKeyCodes.VK_A], dtype=np.int32)
>>> states = keyboard.createBuffer(len(keys))
>>>
>>> while True:
>>>     keyboard.getKeyStates(keys, states)
>>>     print(f"Return: {states[0]:x} Shift: {states[1]:x} Ctrl: {states[2]:x} A: {states[3]:x}")
>>>     if states[0] & KeyState.KEY_DOWN and states[1] & KeyState.KEY_DOWN and states[2] & KeyState.KEY_DOWN: # Press Ctrl+Shift+Enter to exit loop
>>>         break