[libcamera-devel] [PATCH v5 0/3] Python bindings

[David Plowman]

Cool, thanks, I'll try those and let you know!

David

On Thu, 17 Mar 2022 at 11:36, Tomi Valkeinen
<tomi.valkeinen at ideasonboard.com> wrote:
>
> On 17/03/2022 13:01, David Plowman wrote:
> > Hi again
> >
> > On Thu, 17 Mar 2022 at 10:41, Tomi Valkeinen
> > <tomi.valkeinen at ideasonboard.com> wrote:
> >>
> >> On 17/03/2022 12:12, David Plowman wrote:
> >>> Hi again
> >>>
> >>> Just to answer the about about the "enum" type controls:
> >>>
> >>> On Thu, 17 Mar 2022 at 09:55, Tomi Valkeinen
> >>> <tomi.valkeinen at ideasonboard.com> wrote:
> >>>>
> >>>> On 17/03/2022 11:44, David Plowman wrote:
> >>>>> Hi everyone
> >>>>>
> >>>>> Thanks for the update!
> >>>>>
> >>>>> On Mon, 14 Mar 2022 at 15:46, Tomi Valkeinen
> >>>>> <tomi.valkeinen at ideasonboard.com> wrote:
> >>>>>>
> >>>>>> Hi,
> >>>>>>
> >>>>>> This is v5 of the series. The changes to v4:
> >>>>>>
> >>>>>> - Changed to pybind11 'smart_holders' branch which allows us to drop the
> >>>>>>      HACK for Camera public destructor
> >>>>>> - Changed Request.set_control() so that we can drop the HACK for
> >>>>>>      exposing Camera from Request
> >>>>>> - Moved Python enum defs to a separate file for clarity
> >>>>>> - "Forward" declare Python classes to fix docstring issues.
> >>>>>>
> >>>>>> The set_control change breaks the current users of that function.
> >>>>>> Previously you could do this:
> >>>>>>
> >>>>>> req.set_control("Brightness", 1)
> >>>>>>
> >>>>>> Now you need to do:
> >>>>>>
> >>>>>> cid = camera.find_control("Brightness")
> >>>>>> req.set_control(cid, 1)
> >>>>>>
> >>>>>
> >>>>> I see the need for this, and I guess it's fine - obviously we'll hide
> >>>>> that under our Picamera2 API as we wouldn't want our users to have to
> >>>>> do that!
> >>>>
> >>>> Yes, it's not very nice. Then again, having to do a string search every
> >>>> time we call set_control is not good either, at least if we can avoid it
> >>>> (and we can, as above). But I agree that in a higher level API things
> >>>> should be easy. Of course, it would be nice to have both versions even
> >>>> in this low level API, but... if Request doesn't expose camera, I don't
> >>>> think we can do it in a simple way.
> >>>>
> >>>>> There is one further thing I wanted to raise in relation to the Python
> >>>>> bindings for controls, now that a few folks are trying out Picamera2.
> >>>>>
> >>>>> I've had feedback that they don't like the fact that all the "enum"
> >>>>> control values (exposure modes, AWB modes, that kind of thing) are
> >>>>> simple integers up in the Python world. They complain that this makes
> >>>>> them quite unfriendly to use, and I'm inclined to agree! We could
> >>>>> always create Python-level definitions for them, and possibly add code
> >>>>> to convert stuff on the fly, but I wonder if Pybind11 can do anything
> >>>>> more automatic for us?
> >>>>
> >>>> Can you elaborate? Which enums are these?
> >>>
> >>> So users would prefer to write something like
> >>>
> >>> picamera2.set_controls({"AwbMode": AwbMode.Indoor})
> >>>
> >>> rather than
> >>>
> >>> picamera2.set_controls({"AwbMode": 4})
> >>>
> >>> The same applies to all the controls of this type, there including
> >>>
> >>> AeMeteringMode
> >>> AeConstraintMode
> >>> AeExposureMode
> >>> AwbMode
> >>> NoiseReductionMode
> >>> there will at some point be an AfMode and probably other AF ones
> >>> and so on.
> >>>
> >>> Basically it looks to be mostly anything with "Mode" on the end,
> >>> though I think we will encounter some others too. Also anything with
> >>> "State" on the end is probably similar, though in this case we're
> >>> talking about reported values, not ones you can set.
> >>
> >> Looks like these are defined in src/libcamera/control_ids.yaml, so we
> >> could have a script that generates pybind11 code to create the enums. Or
> >> we could just do it by hand.
> >
> > Defining them by hand is fine with me, at least for the time being. I
> > just wonder whether it would get annoying in the longer run, so some
> > kind of script in the build system might be helpful.
> >
> >>
> >> Is that your question, how and where to define the python enums? Or do
> >> you think there's some issue using those?
> >
> > I don't think there's any problem, I guess I'm just flagging that
> > there's something we probably need to do. I could define them all in
> > Picamera2, but it seems like everyone using these Python bindings
> > would appreciate them, so they probably belong in libcamera somewhere.
>
> Ok. I hacked a quick script. Here's a snippet to add to the py .c file if you want to try them:
>
>
>         py::enum_<libcamera::controls::AeMeteringModeEnum>(m, "AeMeteringMode")
>                 .value("CentreWeighted", libcamera::controls::MeteringCentreWeighted)
>                 .value("Spot", libcamera::controls::MeteringSpot)
>                 .value("Matrix", libcamera::controls::MeteringMatrix)
>                 .value("Custom", libcamera::controls::MeteringCustom)
>         ;
>         py::enum_<libcamera::controls::AeConstraintModeEnum>(m, "AeConstraintMode")
>                 .value("Normal", libcamera::controls::ConstraintNormal)
>                 .value("Highlight", libcamera::controls::ConstraintHighlight)
>                 .value("Shadows", libcamera::controls::ConstraintShadows)
>                 .value("Custom", libcamera::controls::ConstraintCustom)
>         ;
>         py::enum_<libcamera::controls::AeExposureModeEnum>(m, "AeExposureMode")
>                 .value("Normal", libcamera::controls::ExposureNormal)
>                 .value("Short", libcamera::controls::ExposureShort)
>                 .value("Long", libcamera::controls::ExposureLong)
>                 .value("Custom", libcamera::controls::ExposureCustom)
>         ;
>         py::enum_<libcamera::controls::AwbModeEnum>(m, "AwbMode")
>                 .value("Auto", libcamera::controls::AwbAuto)
>                 .value("Incandescent", libcamera::controls::AwbIncandescent)
>                 .value("Tungsten", libcamera::controls::AwbTungsten)
>                 .value("Fluorescent", libcamera::controls::AwbFluorescent)
>                 .value("Indoor", libcamera::controls::AwbIndoor)
>                 .value("Daylight", libcamera::controls::AwbDaylight)
>                 .value("Cloudy", libcamera::controls::AwbCloudy)
>                 .value("Custom", libcamera::controls::AwbCustom)
>         ;
>         py::enum_<libcamera::controls::draft::AePrecaptureTriggerEnum>(m, "AePrecaptureTrigger")
>                 .value("Idle", libcamera::controls::draft::AePrecaptureTriggerIdle)
>                 .value("Start", libcamera::controls::draft::AePrecaptureTriggerStart)
>                 .value("Cancel", libcamera::controls::draft::AePrecaptureTriggerCancel)
>         ;
>         py::enum_<libcamera::controls::draft::AfTriggerEnum>(m, "AfTrigger")
>                 .value("Idle", libcamera::controls::draft::AfTriggerIdle)
>                 .value("Start", libcamera::controls::draft::AfTriggerStart)
>                 .value("Cancel", libcamera::controls::draft::AfTriggerCancel)
>         ;
>         py::enum_<libcamera::controls::draft::NoiseReductionModeEnum>(m, "NoiseReductionMode")
>                 .value("Off", libcamera::controls::draft::NoiseReductionModeOff)
>                 .value("Fast", libcamera::controls::draft::NoiseReductionModeFast)
>                 .value("HighQuality", libcamera::controls::draft::NoiseReductionModeHighQuality)
>                 .value("Minimal", libcamera::controls::draft::NoiseReductionModeMinimal)
>                 .value("ZSL", libcamera::controls::draft::NoiseReductionModeZSL)
>         ;
>         py::enum_<libcamera::controls::draft::ColorCorrectionAberrationModeEnum>(m, "ColorCorrectionAberrationMode")
>                 .value("Off", libcamera::controls::draft::ColorCorrectionAberrationOff)
>                 .value("Fast", libcamera::controls::draft::ColorCorrectionAberrationFast)
>                 .value("HighQuality", libcamera::controls::draft::ColorCorrectionAberrationHighQuality)
>         ;
>         py::enum_<libcamera::controls::draft::AeStateEnum>(m, "AeState")
>                 .value("Inactive", libcamera::controls::draft::AeStateInactive)
>                 .value("Searching", libcamera::controls::draft::AeStateSearching)
>                 .value("Converged", libcamera::controls::draft::AeStateConverged)
>                 .value("Locked", libcamera::controls::draft::AeStateLocked)
>                 .value("FlashRequired", libcamera::controls::draft::AeStateFlashRequired)
>                 .value("Precapture", libcamera::controls::draft::AeStatePrecapture)
>         ;
>         py::enum_<libcamera::controls::draft::AfStateEnum>(m, "AfState")
>                 .value("Inactive", libcamera::controls::draft::AfStateInactive)
>                 .value("PassiveScan", libcamera::controls::draft::AfStatePassiveScan)
>                 .value("PassiveFocused", libcamera::controls::draft::AfStatePassiveFocused)
>                 .value("ActiveScan", libcamera::controls::draft::AfStateActiveScan)
>                 .value("FocusedLock", libcamera::controls::draft::AfStateFocusedLock)
>                 .value("NotFocusedLock", libcamera::controls::draft::AfStateNotFocusedLock)
>                 .value("PassiveUnfocused", libcamera::controls::draft::AfStatePassiveUnfocused)
>         ;
>         py::enum_<libcamera::controls::draft::AwbStateEnum>(m, "AwbState")
>                 .value("StateInactive", libcamera::controls::draft::AwbStateInactive)
>                 .value("StateSearching", libcamera::controls::draft::AwbStateSearching)
>                 .value("Converged", libcamera::controls::draft::AwbConverged)
>                 .value("Locked", libcamera::controls::draft::AwbLocked)
>         ;
>         py::enum_<libcamera::controls::draft::LensShadingMapModeEnum>(m, "LensShadingMapMode")
>                 .value("Off", libcamera::controls::draft::LensShadingMapModeOff)
>                 .value("On", libcamera::controls::draft::LensShadingMapModeOn)
>         ;
>         py::enum_<libcamera::controls::draft::SceneFlickerEnum>(m, "SceneFlicker")
>                 .value("Off", libcamera::controls::draft::SceneFickerOff)
>                 .value("50Hz", libcamera::controls::draft::SceneFicker50Hz)
>                 .value("60Hz", libcamera::controls::draft::SceneFicker60Hz)
>         ;
>         py::enum_<libcamera::controls::draft::TestPatternModeEnum>(m, "TestPatternMode")
>                 .value("Off", libcamera::controls::draft::TestPatternModeOff)
>                 .value("SolidColor", libcamera::controls::draft::TestPatternModeSolidColor)
>                 .value("ColorBars", libcamera::controls::draft::TestPatternModeColorBars)
>                 .value("ColorBarsFadeToGray", libcamera::controls::draft::TestPatternModeColorBarsFadeToGray)
>                 .value("Pn9", libcamera::controls::draft::TestPatternModePn9)
>                 .value("Custom1", libcamera::controls::draft::TestPatternModeCustom1)
>         ;
>