[libcamera-devel] [PATCH v3 4/9] libcamera: bayer_format: Add PixelFormat conversion helpers to BayerFormat class

[Naushir Patuck]

Hi,

On Wed, 27 Oct 2021 at 12:48, Laurent Pinchart <
laurent.pinchart at ideasonboard.com> wrote:

> On Wed, Oct 27, 2021 at 11:48:20AM +0100, Kieran Bingham wrote:
> > Quoting Naushir Patuck (2021-10-27 10:27:58)
> > > Add BayerFormat::toPixelFormat() and BayerFormat::fromPixelFormat()
> helper
> > > functions to convert between BayerFormat and PixelFormat types.
> > >
> > > Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> > > Reviewed-by: David Plowman <david.plowman at raspberrypi.com>
> > > ---
> > >  include/libcamera/internal/bayer_format.h |  4 ++++
> > >  src/libcamera/bayer_format.cpp            | 29 +++++++++++++++++++++++
> > >  2 files changed, 33 insertions(+)
> > >
> > > diff --git a/include/libcamera/internal/bayer_format.h
> b/include/libcamera/internal/bayer_format.h
> > > index 723382d4168d..ee96b9a86707 100644
> > > --- a/include/libcamera/internal/bayer_format.h
> > > +++ b/include/libcamera/internal/bayer_format.h
> > > @@ -10,6 +10,8 @@
> > >  #include <stdint.h>
> > >  #include <string>
> > >
> > > +#include <libcamera/pixel_format.h>
> > > +
> > >  #include "libcamera/internal/v4l2_pixelformat.h"
> > >
> > >  namespace libcamera {
> > > @@ -50,6 +52,8 @@ public:
> > >
> > >         V4L2PixelFormat toV4L2PixelFormat() const;
> > >         static BayerFormat fromV4L2PixelFormat(V4L2PixelFormat
> v4l2Format);
> > > +       PixelFormat toPixelFormat() const;
> > > +       static BayerFormat fromPixelFormat(PixelFormat format);
> > >         BayerFormat transform(Transform t) const;
> > >
> > >         Order order;
> > > diff --git a/src/libcamera/bayer_format.cpp
> b/src/libcamera/bayer_format.cpp
> > > index 94e2294d7f6c..1edd238829ce 100644
> > > --- a/src/libcamera/bayer_format.cpp
> > > +++ b/src/libcamera/bayer_format.cpp
> > > @@ -305,6 +305,35 @@ BayerFormat
> BayerFormat::fromV4L2PixelFormat(V4L2PixelFormat v4l2Format)
> > >         return BayerFormat();
> > >  }
> > >
> > > +/**
> > > + * \brief Convert a BayerFormat into the corresponding PixelFormat
> > > + * \return The PixelFormat corresponding to this BayerFormat
> > > + */
> > > +PixelFormat BayerFormat::toPixelFormat() const
> > > +{
> > > +       const auto it = bayerToFormat.find(*this);
> > > +       if (it != bayerToFormat.end())
> > > +               return it->second.pixelFormat;
> > > +
> > > +       return PixelFormat();
> > > +}
> > > +
> > > +/**
> > > + * \brief Convert a PixelFormat into the corresponding BayerFormat
> > > + * \return The BayerFormat corresponding to this PixelFormat
> > > + */
> > > +BayerFormat BayerFormat::fromPixelFormat(PixelFormat format)
> > > +{
> > > +       auto it = std::find_if(bayerToFormat.begin(),
> bayerToFormat.end(),
> > > +                              [format](const auto &i) {
> > > +                                      return i.second.pixelFormat ==
> format;
> > > +                              });
> > > +       if (it == bayerToFormat.end())
> > > +               return BayerFormat{};
> > > +
> > > +       return it->first;
> >
> > I'm curious why you have used two styles in the two functions.
> >
> > BayerFormat::toPixelFormat is
> >   if (it != end)
> >      return it;
> >   return Empty;
> >
> > while BayerFormat::fromPixelFormat is
> >   if (it == end)
> >      return Empty;
> >
> >   return it;
> >
> > If there's no technical reason for this, I think keeping them both using
> > the same pattern would be more consistent, but ... they are both
> > functional, so I don't see this as a blocker. (Personally I'd use the
> > BayerFormat::toPixelFormat style on both)
>
> Funny how personal preferences differ, I would have used the latter
> (a.k.a. return on error) style :-)
>

I'll use the  BayerFormat::toPixelFormat style this time round as that
matches
what the other functions in this file do.

Regards,
Naush


> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>
> > So either way:
> >
> > Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> >
> > > +}
> > > +
> > >  /**
> > >   * \brief Apply a transform to this BayerFormat
> > >   * \param[in] t The transform to apply
>
> --
> Regards,
>
> Laurent Pinchart
>
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