kmk-paintbrush/kmk/scanners/digitalio.py

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import digitalio
from keypad import Event as KeyEvent
from kmk.scanners import DiodeOrientation, Scanner
class MatrixScanner(Scanner):
def __init__(
self,
cols,
rows,
diode_orientation=DiodeOrientation.COLUMNS,
rollover_cols_every_rows=None,
offset=0,
):
self.len_cols = len(cols)
self.len_rows = len(rows)
self.offset = offset
# A pin cannot be both a row and column, detect this by combining the
# two tuples into a set and validating that the length did not drop
#
# repr() hackery is because CircuitPython Pin objects are not hashable
unique_pins = {repr(c) for c in cols} | {repr(r) for r in rows}
assert (
len(unique_pins) == self.len_cols + self.len_rows
), 'Cannot use a pin as both a column and row'
del unique_pins
self.diode_orientation = diode_orientation
# __class__.__name__ is used instead of isinstance as the MCP230xx lib
# does not use the digitalio.DigitalInOut, but rather a self defined one:
# https://github.com/adafruit/Adafruit_CircuitPython_MCP230xx/blob/3f04abbd65ba5fa938fcb04b99e92ae48a8c9406/adafruit_mcp230xx/digital_inout.py#L33
if self.diode_orientation == DiodeOrientation.COLUMNS:
self.outputs = [
x
if x.__class__.__name__ == 'DigitalInOut'
else digitalio.DigitalInOut(x)
for x in cols
]
self.inputs = [
x
if x.__class__.__name__ == 'DigitalInOut'
else digitalio.DigitalInOut(x)
for x in rows
]
self.translate_coords = True
elif self.diode_orientation == DiodeOrientation.ROWS:
self.outputs = [
x
if x.__class__.__name__ == 'DigitalInOut'
else digitalio.DigitalInOut(x)
for x in rows
]
self.inputs = [
x
if x.__class__.__name__ == 'DigitalInOut'
else digitalio.DigitalInOut(x)
for x in cols
]
self.translate_coords = False
else:
raise ValueError(f'Invalid DiodeOrientation: {self.diode_orienttaion}')
for pin in self.outputs:
pin.switch_to_output()
for pin in self.inputs:
pin.switch_to_input(pull=digitalio.Pull.DOWN)
self.rollover_cols_every_rows = rollover_cols_every_rows
if self.rollover_cols_every_rows is None:
self.rollover_cols_every_rows = self.len_rows
self._key_count = self.len_cols * self.len_rows
self.state = bytearray(self.key_count)
@property
def key_count(self):
return self._key_count
def scan_for_changes(self):
'''
Poll the matrix for changes and return either None (if nothing updated)
or a bytearray (reused in later runs so copy this if you need the raw
array itself for some crazy reason) consisting of (row, col, pressed)
which are (int, int, bool)
'''
ba_idx = 0
any_changed = False
for oidx, opin in enumerate(self.outputs):
opin.value = True
for iidx, ipin in enumerate(self.inputs):
# cast to int to avoid
#
# >>> xyz = bytearray(3)
# >>> xyz[2] = True
# Traceback (most recent call last):
# File "<stdin>", line 1, in <module>
# OverflowError: value would overflow a 1 byte buffer
#
# I haven't dived too far into what causes this, but it's
# almost certainly because bool types in Python aren't just
# aliases to int values, but are proper pseudo-types
new_val = int(ipin.value)
old_val = self.state[ba_idx]
if old_val != new_val:
if self.translate_coords:
new_oidx = oidx + self.len_cols * (
iidx // self.rollover_cols_every_rows
)
new_iidx = iidx - self.rollover_cols_every_rows * (
iidx // self.rollover_cols_every_rows
)
row = new_iidx
col = new_oidx
else:
row = oidx
col = iidx
pressed = new_val
self.state[ba_idx] = new_val
any_changed = True
break
ba_idx += 1
opin.value = False
if any_changed:
break
if any_changed:
key_number = self.len_cols * row + col + self.offset
return KeyEvent(key_number, pressed)