[libcamera-devel] [PATCH 0/5] libcamera: More operator<<() for stream output

[Laurent Pinchart]

Hi Jacopo,

On Tue, May 03, 2022 at 09:04:14AM +0200, Jacopo Mondi wrote:
> Hi Laurent,
> 
> On Sat, Apr 30, 2022 at 12:23:43AM +0300, Laurent Pinchart via libcamera-devel wrote:
> > Hello,
> >
> > This patch series extends Han-Lin's operator<<() implementation for
> > geometry classes to format classes. There isn't much else to mention in
> > the cover letter, please see individual patches for details.
> 
> We now have both .toString() and operator<< for printing. Is this
> intentional ? Shouldn't we stabilize on only one of the two ?

I think both make sense (as long as one of the two is implemented based
on the other internally), as they serve different purposes. operator<<()
certainly simplifies logging, but not all string representations are
used in logs. toString() has few users so far, mostly in tests, for
instance in

	if (PixelFormat().toString() != "<INVALID>") {
		cerr << "Failed to convert default PixelFormat to string"
		     << endl;
		return TestFail;
	}

It would need to be written as

	std::stringstream ss;
	ss << PixelFormat();
	if (ss.str() != "<INVALID>") {
		...
	}

which isn't very convenient. I can imagine more use cases in
applications, for instance in qcam where available resolutions could be
displayed in the UI.

> > Laurent Pinchart (5):
> >   libcamera: geometry: Add missing ostream header in geometry.h
> >   libcamera: Add operator<<() for pixel format classes
> >   libcamera: bayer_format: Add operator<<()
> >   libcamera: Add operator<<() for V4L2 format classes
> >   libcamera: Replace toString with operator<<() for format classes
> >
> >  include/libcamera/geometry.h                  |  1 +
> >  include/libcamera/internal/bayer_format.h     |  3 +
> >  include/libcamera/internal/v4l2_pixelformat.h |  3 +
> >  include/libcamera/internal/v4l2_subdevice.h   |  3 +
> >  include/libcamera/internal/v4l2_videodevice.h |  3 +
> >  include/libcamera/pixel_format.h              |  3 +
> >  src/android/camera_capabilities.cpp           |  6 +-
> >  src/android/camera_device.cpp                 |  4 +-
> >  src/android/jpeg/encoder_libjpeg.cpp          |  2 +-
> >  src/android/jpeg/thumbnailer.cpp              |  2 +-
> >  src/android/mm/generic_camera_buffer.cpp      |  3 +-
> >  src/android/yuv/post_processor_yuv.cpp        |  4 +-
> >  src/cam/camera_session.cpp                    |  2 +-
> >  src/cam/kms_sink.cpp                          |  2 +-
> >  src/libcamera/bayer_format.cpp                | 57 ++++++++++++-------
> >  src/libcamera/pipeline/ipu3/cio2.cpp          |  2 +-
> >  src/libcamera/pipeline/ipu3/imgu.cpp          |  6 +-
> >  .../pipeline/raspberrypi/raspberrypi.cpp      | 20 +++----
> >  src/libcamera/pipeline/rkisp1/rkisp1.cpp      | 10 ++--
> >  src/libcamera/pipeline/rkisp1/rkisp1_path.cpp |  6 +-
> >  src/libcamera/pipeline/simple/converter.cpp   |  4 +-
> >  src/libcamera/pipeline/simple/simple.cpp      |  9 ++-
> >  src/libcamera/pipeline/uvcvideo/uvcvideo.cpp  |  5 +-
> >  src/libcamera/pipeline/vimc/vimc.cpp          |  2 +-
> >  src/libcamera/pixel_format.cpp                | 12 ++++
> >  src/libcamera/v4l2_pixelformat.cpp            | 13 +++++
> >  src/libcamera/v4l2_subdevice.cpp              | 36 ++++++++----
> >  src/libcamera/v4l2_videodevice.cpp            | 16 +++++-
> >  src/qcam/viewfinder_qt.cpp                    |  3 +-
> >  src/v4l2/v4l2_camera_proxy.cpp                |  2 +-
> >  test/bayer-format.cpp                         | 24 ++++----
> >  test/camera-sensor.cpp                        |  2 +-
> >  32 files changed, 175 insertions(+), 95 deletions(-)

-- 
Regards,

Laurent Pinchart