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keyboard.py
keyboard.py 6.74 KiB
# SPDX-FileCopyrightText: 2017 Dan Halbert for Adafruit Industries
#
# SPDX-License-Identifier: MIT
"""
`adafruit_hid.keyboard.Keyboard`
====================================================
* Author(s): Scott Shawcroft, Dan Halbert
"""
import time
from micropython import const
import usb_hid
from .keycode import Keycode
from . import find_device
try:
from typing import Sequence
except: # pylint: disable=bare-except
pass
_MAX_KEYPRESSES = const(6)
class Keyboard:
"""Send HID keyboard reports."""
LED_NUM_LOCK = 0x01
"""LED Usage ID for Num Lock"""
LED_CAPS_LOCK = 0x02
"""LED Usage ID for Caps Lock"""
LED_SCROLL_LOCK = 0x04
"""LED Usage ID for Scroll Lock"""
LED_COMPOSE = 0x08
"""LED Usage ID for Compose"""
# No more than _MAX_KEYPRESSES regular keys may be pressed at once.
def __init__(self, devices: Sequence[usb_hid.Device]) -> None:
"""Create a Keyboard object that will send keyboard HID reports.
Devices can be a sequence of devices that includes a keyboard device or a keyboard device
itself. A device is any object that implements ``send_report()``, ``usage_page`` and
``usage``.
"""
self._keyboard_device = find_device(devices, usage_page=0x1, usage=0x06)
# Reuse this bytearray to send keyboard reports.
self.report = bytearray(8)
# report[0] modifiers
# report[1] unused
# report[2:8] regular key presses
# View onto byte 0 in report.
self.report_modifier = memoryview(self.report)[0:1]
# List of regular keys currently pressed.
# View onto bytes 2-7 in report.
self.report_keys = memoryview(self.report)[2:]
# No keyboard LEDs on.
self._led_status = b"\x00"
# Do a no-op to test if HID device is ready.
# If not, wait a bit and try once more.
try:
self.release_all()
except OSError:
time.sleep(1)
self.release_all()
def press(self, *keycodes: int) -> None:
"""Send a report indicating that the given keys have been pressed.
:param keycodes: Press these keycodes all at once.
:raises ValueError: if more than six regular keys are pressed.
Keycodes may be modifiers or regular keys.
No more than six regular keys may be pressed simultaneously.
Examples::
from adafruit_hid.keycode import Keycode
# Press ctrl-x.
kbd.press(Keycode.LEFT_CONTROL, Keycode.X)
# Or, more conveniently, use the CONTROL alias for LEFT_CONTROL:
kbd.press(Keycode.CONTROL, Keycode.X)
# Press a, b, c keys all at once.
kbd.press(Keycode.A, Keycode.B, Keycode.C)
"""
for keycode in keycodes:
self._add_keycode_to_report(keycode)
self._keyboard_device.send_report(self.report)
def release(self, *keycodes: int) -> None:
"""Send a USB HID report indicating that the given keys have been released.
:param keycodes: Release these keycodes all at once.
If a keycode to be released was not pressed, it is ignored.
Example::
# release SHIFT key
kbd.release(Keycode.SHIFT)
"""
for keycode in keycodes:
self._remove_keycode_from_report(keycode)
self._keyboard_device.send_report(self.report)
def release_all(self) -> None:
"""Release all pressed keys."""
for i in range(8):
self.report[i] = 0
self._keyboard_device.send_report(self.report)
def send(self, *keycodes: int) -> None:
"""Press the given keycodes and then release all pressed keys.
:param keycodes: keycodes to send together
"""
self.press(*keycodes)
self.release_all()
def _add_keycode_to_report(self, keycode: int) -> None:
"""Add a single keycode to the USB HID report."""
modifier = Keycode.modifier_bit(keycode)
if modifier:
# Set bit for this modifier.
self.report_modifier[0] |= modifier
else:
report_keys = self.report_keys
# Don't press twice.
for i in range(_MAX_KEYPRESSES):
report_key = report_keys[i]
if report_key == 0:
# Put keycode in first empty slot. Since the report_keys
# are compact and unique, this is not a repeated key
report_keys[i] = keycode
return
if report_key == keycode:
# Already pressed.
return
# All slots are filled. Shuffle down and reuse last slot
for i in range(_MAX_KEYPRESSES - 1):
report_keys[i] = report_keys[i + 1]
report_keys[-1] = keycode
def _remove_keycode_from_report(self, keycode: int) -> None:
"""Remove a single keycode from the report."""
modifier = Keycode.modifier_bit(keycode)
if modifier:
# Turn off the bit for this modifier.
self.report_modifier[0] &= ~modifier
else:
report_keys = self.report_keys
# Clear the at most one matching slot and move remaining keys down
j = 0
for i in range(_MAX_KEYPRESSES):
pressed = report_keys[i]
if not pressed:
break # Handled all used report slots
if pressed == keycode:
continue # Remove this entry
if i != j:
report_keys[j] = report_keys[i]
j += 1
# Clear any remaining slots
while j < _MAX_KEYPRESSES and report_keys[j]:
report_keys[j] = 0
j += 1
@property
def led_status(self) -> bytes:
"""Returns the last received report"""
# get_last_received_report() returns None when nothing was received
led_report = self._keyboard_device.get_last_received_report()
if led_report is not None:
self._led_status = led_report
return self._led_status
def led_on(self, led_code: int) -> bool:
"""Returns whether an LED is on based on the led code
Examples::
import usb_hid
from adafruit_hid.keyboard import Keyboard
from adafruit_hid.keycode import Keycode
import time
# Initialize Keyboard
kbd = Keyboard(usb_hid.devices)
# Press and release CapsLock.
kbd.press(Keycode.CAPS_LOCK)
time.sleep(.09)
kbd.release(Keycode.CAPS_LOCK)
# Check status of the LED_CAPS_LOCK
print(kbd.led_on(Keyboard.LED_CAPS_LOCK))
"""
return bool(self.led_status[0] & led_code)