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

[Laurent Pinchart]

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 :-)

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