This finishes off implementing values and source for all (current)
classes in gpiozero. I'm afraid things get rather complex in this
commit. For starters, we've now got quite a few "aggregate" classes
which necessarily don't descend from GPIODevice. To implement values and
source on these I could either repeat a helluva lot of code or ... turn
to mixin classes. Yeah, it's multiple inheritance time, baby!
Unfortunately multiple inheritance doesn't work with __slots__ but we
really ought to keep functionality that they provide us (raise
AttributeError when an unknown attribute is set). So I've implemented
this with ... erm ... metaclasses. Sorry!
Makes `value` an alias of `is_active` in the base `GPIODevice`, and
`values` an infinite iterable of this value. Then adds `source` property
to `OutputDevice` allowing simple linkage of devices via iterators.
Add more property aliases and do them properly (no more lambdas and
string lookups) which means we can remove `_alias`. This commit also
defines `__slots__` for all classes which should prevent assignation of
invalid attributes with an AttributeError (more friendly than silently
doing the wrong thing). Finally, it cleans up all the property defs to
use Ben's preferred decorator style.
This PR adds the `active_high` parameter (defaulted to `True`) to the
`OutputDevice` class. This permits flipping the logic of an output
device in a similar manner to `pull_up` on `InputDevice`.
It also adds a `Relay` class derived from `DigitalOutputDevice` which
uses this parameter to flip the logic (as this is typically required
with relays).
Actually, this isn't so much a fix as a re-working of RGBLED. This
renames the `rgb` property to `color` because that's what the property
really represents (combined with `picamera.Color` this lets you do stuff
like `rgb_led.color = Color('red')`), and simplifies the internals of
the class. It also adds the common `close` method and context manager
capabilities.
Finally, it corrects an error I hadn't noticed earlier where
PWMOutputDevice isn't properly cleaning up PWM threads on close.
Make MotionSensor more responsive by effectively removing the averaging
queue. Also add note on how to smooth out "jittery" PIR sensors by
increasing the queue length back up to 5.
Something fishy going on with the Markdown for the code examples in the
Notes page. Might be down to the indentation of the list item's content?
The vim markdown parser seems to think so anyway; let's see what
pythonhosted.org says ...
This refactors the GPIOOutputDevice to have an internal `_write` method
similar to the `_read` method used to grab the value of a GPIO device.
This is used for simple 1s and 0s until we get to PWMOutputDevice which
replaces the value with the PWM device's duty cycle level. As a result,
all the DigitalOutputDevice base methods (including blink) "just work".
This commit also, for the moment, removes min_pwm and max_pwm because
I'm not 100% certain how they should interact with the notion of
is_active at the moment. They'll probably get added back in at some
point but I need a bit more time to think about it!
This isn't a full fix but I can't seem to reproduce the issue in #50 at
the moment. So for now this just ensures that exceptions in the
constructors get cleaned up properly (so they don't block future
construction attempts against the same pin)
