[libcamera-devel] [PATCH v3 3/4] apply explicit fixed-sized Span type casts
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Tue Apr 19 22:46:18 CEST 2022
Hi Christian,
Thank you for the patch.
On Fri, Apr 08, 2022 at 02:42:30AM +0100, Christian Rauch via libcamera-devel wrote:
> The change of types of some Controls from variable- to fixed-sized requires
> explicit casting of FrameDurationLimits, ColourGains and SensorBlackLevels.
>
> Signed-off-by: Christian Rauch <Rauch.Christian at gmx.de>
> ---
> src/ipa/raspberrypi/raspberrypi.cpp | 18 +++++++++---------
> .../pipeline/raspberrypi/raspberrypi.cpp | 2 +-
> src/qcam/dng_writer.cpp | 6 +++---
> 3 files changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/src/ipa/raspberrypi/raspberrypi.cpp b/src/ipa/raspberrypi/raspberrypi.cpp
> index 89767a9d..5a5cdf66 100644
> --- a/src/ipa/raspberrypi/raspberrypi.cpp
> +++ b/src/ipa/raspberrypi/raspberrypi.cpp
> @@ -500,18 +500,18 @@ void IPARPi::reportMetadata()
>
> AwbStatus *awbStatus = rpiMetadata_.GetLocked<AwbStatus>("awb.status");
> if (awbStatus) {
> - libcameraMetadata_.set(controls::ColourGains, { static_cast<float>(awbStatus->gain_r),
> - static_cast<float>(awbStatus->gain_b) });
> + libcameraMetadata_.set(controls::ColourGains, Span<const float, 2>({ static_cast<float>(awbStatus->gain_r),
> + static_cast<float>(awbStatus->gain_b) }));
Those lines are too long. I'm bothered here, as I think it's very nice
to use fixed-extent spans to catch errors at compilation time, but the
cast is ugly :-( This is caused by the explicit constructor for
fixed-extent spans, which we can't change if we want to remain
compatible with std::span.
I was also wondering it we could drop the static_cast<float> to
compensate for the additional explicit constructor, but that generates
other errors:
../../src/ipa/raspberrypi/raspberrypi.cpp:505:72: error: non-constant-expression cannot be narrowed from type 'double' to 'libcamera::Span<const float, 2>::element_type' (aka 'const float') in initializer list [-Wc++11-narrowing]
libcameraMetadata_.set(controls::ColourGains, Span<const float, 2>({ awbStatus->gain_r,
^~~~~~~~~~~~~~~~~
../../src/ipa/raspberrypi/raspberrypi.cpp:505:72: note: insert an explicit cast to silence this issue
libcameraMetadata_.set(controls::ColourGains, Span<const float, 2>({ awbStatus->gain_r,
^~~~~~~~~~~~~~~~~
static_cast<element_type>( )
../../src/ipa/raspberrypi/raspberrypi.cpp:506:16: error: non-constant-expression cannot be narrowed from type 'double' to 'libcamera::Span<const float, 2>::element_type' (aka 'const float') in initializer list [-Wc++11-narrowing]
awbStatus->gain_b }));
^~~~~~~~~~~~~~~~~
../../src/ipa/raspberrypi/raspberrypi.cpp:506:16: note: insert an explicit cast to silence this issue
awbStatus->gain_b }));
^~~~~~~~~~~~~~~~~
static_cast<element_type>( )
2 errors generated.
I suppose stars don't always align.
With proper line wraps, such as
libcameraMetadata_.set(controls::ColourGains,
Span<const float, 2>({ static_cast<float>(awbStatus->gain_r),
static_cast<float>(awbStatus->gain_b) }));
or maybe
libcameraMetadata_.set(controls::ColourGains, Span<const float, 2>({
static_cast<float>(awbStatus->gain_r),
static_cast<float>(awbStatus->gain_b) }));
I'm OK with this patch. I'd like to hear from others though. Bonus
points if someone can find a nicer way to express all this. We could,
for instance, add new ControlList::set() overloads specialized for
spans.
> libcameraMetadata_.set(controls::ColourTemperature, awbStatus->temperature_K);
> }
>
> BlackLevelStatus *blackLevelStatus = rpiMetadata_.GetLocked<BlackLevelStatus>("black_level.status");
> if (blackLevelStatus)
> libcameraMetadata_.set(controls::SensorBlackLevels,
> - { static_cast<int32_t>(blackLevelStatus->black_level_r),
> - static_cast<int32_t>(blackLevelStatus->black_level_g),
> - static_cast<int32_t>(blackLevelStatus->black_level_g),
> - static_cast<int32_t>(blackLevelStatus->black_level_b) });
> + Span<const int32_t, 4>({ static_cast<int32_t>(blackLevelStatus->black_level_r),
> + static_cast<int32_t>(blackLevelStatus->black_level_g),
> + static_cast<int32_t>(blackLevelStatus->black_level_g),
> + static_cast<int32_t>(blackLevelStatus->black_level_b) }));
>
> FocusStatus *focusStatus = rpiMetadata_.GetLocked<FocusStatus>("focus.status");
> if (focusStatus && focusStatus->num == 12) {
> @@ -816,7 +816,7 @@ void IPARPi::queueRequest(const ControlList &controls)
> if (gains[0] != 0.0f && gains[1] != 0.0f)
> /* A gain of 0.0f will switch back to auto mode. */
> libcameraMetadata_.set(controls::ColourGains,
> - { gains[0], gains[1] });
> + Span<const float, 2>({ gains[0], gains[1] }));
> break;
> }
>
> @@ -1100,8 +1100,8 @@ void IPARPi::applyFrameDurations(Duration minFrameDuration, Duration maxFrameDur
>
> /* Return the validated limits via metadata. */
> libcameraMetadata_.set(controls::FrameDurationLimits,
> - { static_cast<int64_t>(minFrameDuration_.get<std::micro>()),
> - static_cast<int64_t>(maxFrameDuration_.get<std::micro>()) });
> + Span<const int64_t, 2>({ static_cast<int64_t>(minFrameDuration_.get<std::micro>()),
> + static_cast<int64_t>(maxFrameDuration_.get<std::micro>()) }));
>
> /*
> * Calculate the maximum exposure time possible for the AGC to use.
> diff --git a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> index d6148724..0fa294d4 100644
> --- a/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/raspberrypi.cpp
> @@ -1696,7 +1696,7 @@ void RPiCameraData::statsMetadataComplete(uint32_t bufferId, const ControlList &
> * V4L2_CID_NOTIFY_GAINS control (which means notifyGainsUnity_ is set).
> */
> if (notifyGainsUnity_ && controls.contains(libcamera::controls::ColourGains)) {
> - libcamera::Span<const float> colourGains = controls.get(libcamera::controls::ColourGains);
> + libcamera::Span<const float, 2> colourGains = controls.get(libcamera::controls::ColourGains);
> /* The control wants linear gains in the order B, Gb, Gr, R. */
> ControlList ctrls(sensor_->controls());
> std::array<int32_t, 4> gains{
> diff --git a/src/qcam/dng_writer.cpp b/src/qcam/dng_writer.cpp
> index 34c8df5a..2fb527d8 100644
> --- a/src/qcam/dng_writer.cpp
> +++ b/src/qcam/dng_writer.cpp
> @@ -438,7 +438,7 @@ int DNGWriter::write(const char *filename, const Camera *camera,
> const double eps = 1e-2;
>
> if (metadata.contains(controls::ColourGains)) {
> - Span<const float> const &colourGains = metadata.get(controls::ColourGains);
> + Span<const float, 2> const &colourGains = metadata.get(controls::ColourGains);
> if (colourGains[0] > eps && colourGains[1] > eps) {
> wbGain = Matrix3d::diag(colourGains[0], 1, colourGains[1]);
> neutral[0] = 1.0 / colourGains[0]; /* red */
> @@ -446,7 +446,7 @@ int DNGWriter::write(const char *filename, const Camera *camera,
> }
> }
> if (metadata.contains(controls::ColourCorrectionMatrix)) {
> - Span<const float> const &coeffs = metadata.get(controls::ColourCorrectionMatrix);
> + Span<const float, 9> const &coeffs = metadata.get(controls::ColourCorrectionMatrix);
> Matrix3d ccmSupplied(coeffs);
> if (ccmSupplied.determinant() > eps)
> ccm = ccmSupplied;
> @@ -515,7 +515,7 @@ int DNGWriter::write(const char *filename, const Camera *camera,
> uint32_t whiteLevel = (1 << info->bitsPerSample) - 1;
>
> if (metadata.contains(controls::SensorBlackLevels)) {
> - Span<const int32_t> levels = metadata.get(controls::SensorBlackLevels);
> + Span<const int32_t, 4> levels = metadata.get(controls::SensorBlackLevels);
>
> /*
> * The black levels control is specified in R, Gr, Gb, B order.
--
Regards,
Laurent Pinchart
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