[libcamera-devel] [PATCH v7 09/13] py: add Transform

[Laurent Pinchart]

Hi Tomi,

Thank you for the patch.

On Thu, May 05, 2022 at 01:41:00PM +0300, Tomi Valkeinen wrote:
> Add binding for Transform.
> 
> C++'s Transform is an enum class, but we expose it as a Python class so
> that it can be easily manipulated.
> 
> Original version from David Plowman <david.plowman at raspberrypi.com>.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
> ---
>  src/py/libcamera/pymain.cpp | 63 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 62 insertions(+), 1 deletion(-)
> 
> diff --git a/src/py/libcamera/pymain.cpp b/src/py/libcamera/pymain.cpp
> index db9d90ab..3d2393ab 100644
> --- a/src/py/libcamera/pymain.cpp
> +++ b/src/py/libcamera/pymain.cpp
> @@ -152,6 +152,7 @@ PYBIND11_MODULE(_libcamera, m)
>  	auto pyControlId = py::class_<ControlId>(m, "ControlId");
>  	auto pyRequest = py::class_<Request>(m, "Request");
>  	auto pyFrameMetadata = py::class_<FrameMetadata>(m, "FrameMetadata");
> +	auto pyTransform = py::class_<Transform>(m, "Transform");
>  
>  	/* Global functions */
>  	m.def("logSetLevel", &logSetLevel);
> @@ -342,7 +343,8 @@ PYBIND11_MODULE(_libcamera, m)
>  		.def("validate", &CameraConfiguration::validate)
>  		.def("at", py::overload_cast<unsigned int>(&CameraConfiguration::at), py::return_value_policy::reference_internal)
>  		.def_property_readonly("size", &CameraConfiguration::size)
> -		.def_property_readonly("empty", &CameraConfiguration::empty);
> +		.def_property_readonly("empty", &CameraConfiguration::empty)
> +		.def_readwrite("transform", &CameraConfiguration::transform);
>  
>  	pyStreamConfiguration
>  		.def("toString", &StreamConfiguration::toString)
> @@ -462,4 +464,63 @@ PYBIND11_MODULE(_libcamera, m)
>  			transform(self.planes().begin(), self.planes().end(), v.begin(), [](const auto &p) { return p.bytesused; });
>  			return v;
>  		});
> +
> +	pyTransform
> +		.def(py::init([](int rotation, bool hflip, bool vflip, bool transpose) {

I'm not fond of the constructor, three bool arguments in a row are quite
error-prone. I'd rather expose the enum.

> +			bool ok;
> +
> +			Transform t = transformFromRotation(rotation, &ok);
> +			if (!ok)
> +				throw std::runtime_error("Unable to create the transform");

"Invalid rotation" would be a better message I think.

> +
> +			if (hflip)
> +				t ^= Transform::HFlip;
> +			if (vflip)
> +				t ^= Transform::VFlip;
> +			if (transpose)
> +				t ^= Transform::Transpose;
> +			return t;
> +		}), py::arg("rotation") = 0, py::arg("hflip") = false,
> +		    py::arg("vflip") = false, py::arg("transpose") = false)
> +		.def(py::init([](Transform &other) { return other; }))
> +		.def("__repr__", [](Transform &self) {
> +			return "<libcamera.Transform '" + std::string(transformToString(self)) + "'>";
> +		})
> +		.def_property("hflip",
> +			      [](Transform &self) {
> +				      return !!(self & Transform::HFlip);
> +			      },
> +			      [](Transform &self, bool hflip) {
> +				      if (hflip)
> +					      self |= Transform::HFlip;
> +				      else
> +					      self &= ~Transform::HFlip;
> +			      })
> +		.def_property("vflip",
> +			      [](Transform &self) {
> +				      return !!(self & Transform::VFlip);
> +			      },
> +			      [](Transform &self, bool vflip) {
> +				      if (vflip)
> +					      self |= Transform::VFlip;
> +				      else
> +					      self &= ~Transform::VFlip;
> +			      })
> +		.def_property("transpose",
> +			      [](Transform &self) {
> +				      return !!(self & Transform::Transpose);
> +			      },
> +			      [](Transform &self, bool transpose) {
> +				      if (transpose)
> +					      self |= Transform::Transpose;
> +				      else
> +					      self &= ~Transform::Transpose;
> +			      })
> +		.def("inverse", [](Transform &self) { return -self; })
> +		.def("invert", [](Transform &self) {
> +			self = -self;
> +		})
> +		.def("compose", [](Transform &self, Transform &other) {
> +			self = self * other;
> +		});
>  }

-- 
Regards,

Laurent Pinchart