[PATCH 4/4] apps: cam: Print control direction information

[Paul Elder]

On Tue, Nov 26, 2024 at 01:22:47AM +0200, Laurent Pinchart wrote:
> Hi Paul,
> 
> Thank you for the patch.
> 
> On Tue, Nov 26, 2024 at 12:30:03AM +0900, Paul Elder wrote:
> > Now that there is support for retrieving the allowed directions of a
> > control, print this information when listing controls.
> > 
> > Sample output:
> > $ cam --list-controls -c 2
> > Using camera Virtual0 as cam0
> > Control: [io] draft::FaceDetectMode:
> >   - FaceDetectModeOff (0)
> > Control: [i ] libcamera::FrameDurationLimits: [16666..33333]
> 
> I was expecting [in], [out] or [input], but i/o has the advantage of
> aligning the controls names. We could still achieve the same with
> 
> [in   ]
> [  out]
> [inout]

Yeah I'll expand it to this at least. Single-characters are indeed
cryptic.

> 
> at the cost of longer lines, or
> 
> '[in]   '
> '[out]  '
> '[inout]'
> 
> any opinion from anyone ?
> 
> >    Size: 2
> > 
> > Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> > ---
> >  src/apps/cam/camera_session.cpp | 10 ++++++++--
> >  1 file changed, 8 insertions(+), 2 deletions(-)
> > 
> > diff --git a/src/apps/cam/camera_session.cpp b/src/apps/cam/camera_session.cpp
> > index 6e9890ccfda1..1baf36fcfd3c 100644
> > --- a/src/apps/cam/camera_session.cpp
> > +++ b/src/apps/cam/camera_session.cpp
> > @@ -159,12 +159,18 @@ CameraSession::~CameraSession()
> >  void CameraSession::listControls() const
> >  {
> >  	for (const auto &[id, info] : camera_->controls()) {
> > +		std::stringstream io;
> > +		io << "["
> > +		   << (id->isInput() ? "i" : " ")
> > +		   << (id->isOutput() ? "o" : " ")
> > +		   << "] ";
> 
> I wonder if a stringstream is overkill here, maybe you could fold the
> "[" and "]" in the statements below, and just construct a string here.
> It also depends on the outcome of the above discussion. Up to you.

I'd rather not duplicate this twice below...


Paul

> 
> > +
> >  		if (info.values().empty()) {
> > -			std::cout << "Control: "
> > +			std::cout << "Control: " << io.str()
> >  				  << id->vendor() << "::" << id->name() << ": "
> >  				  << info.toString() << std::endl;
> >  		} else {
> > -			std::cout << "Control: "
> > +			std::cout << "Control: " << io.str()
> >  				  << id->vendor() << "::" << id->name() << ":"
> >  				  << std::endl;
> >  			for (const auto &value : info.values()) {