[libcamera-devel] [PATCH v2 1/4] libcamera: Add the fromV4L2PixelFormat function

[Sebastian Fricke]

Hey everyone,

I have noticed that I forgot to remove the declaration from the header
file. This will be fixed in V3.

On 31.12.2020 16:53, Sebastian Fricke wrote:
>Add a static member function to get the corresponding Bayer-format
>from a given V4L2PixelFormat.
>Replace an existing method to instantiate an object from a matching
>V4l2PixelFormat, to not duplicate the code.
>The motivation behind this patch is to align the overall structure
>of the BayerFormat class with other parts of the code base, such as
>the V4L2PixelFormat class.
>
>Remove the v4l2ToBayer mapping table and use the bayerToV4l2 mapping
>table by searching for a mapped element to get the corresponding key.
>The downside of this approach is a slightly worse time complexity, but
>the upside is a smaller codebase and lower memory consumption. As the
>function is probably not used very frequently, I tend to favor the
>mentioned upsides.
>
>Signed-off-by: Sebastian Fricke <sebastian.fricke.linux at gmail.com>
>---
> include/libcamera/internal/bayer_format.h |  1 +
> src/libcamera/bayer_format.cpp            | 63 +++++++----------------
> 2 files changed, 19 insertions(+), 45 deletions(-)
>
>diff --git a/include/libcamera/internal/bayer_format.h b/include/libcamera/internal/bayer_format.h
>index 4280b76b..8efe1382 100644
>--- a/include/libcamera/internal/bayer_format.h
>+++ b/include/libcamera/internal/bayer_format.h
>@@ -48,6 +48,7 @@ public:
> 	std::string toString() const;
>
> 	V4L2PixelFormat toV4L2PixelFormat() const;
>+	static BayerFormat fromV4L2PixelFormat(V4L2PixelFormat v4l2Format);
> 	BayerFormat transform(Transform t) const;
>
> 	Order order;
>diff --git a/src/libcamera/bayer_format.cpp b/src/libcamera/bayer_format.cpp
>index c42792ff..26065b66 100644
>--- a/src/libcamera/bayer_format.cpp
>+++ b/src/libcamera/bayer_format.cpp
>@@ -7,6 +7,7 @@
>
> #include "libcamera/internal/bayer_format.h"
>
>+#include <algorithm>
> #include <map>
>
> #include <libcamera/transform.h>
>@@ -57,37 +58,6 @@ namespace libcamera {
>
> namespace {
>
>-const std::map<V4L2PixelFormat, BayerFormat> v4l2ToBayer{
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SBGGR8), { BayerFormat::BGGR, 8, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGBRG8), { BayerFormat::GBRG, 8, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGRBG8), { BayerFormat::GRBG, 8, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SRGGB8), { BayerFormat::RGGB, 8, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SBGGR10), { BayerFormat::BGGR, 10, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGBRG10), { BayerFormat::GBRG, 10, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGRBG10), { BayerFormat::GRBG, 10, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SRGGB10), { BayerFormat::RGGB, 10, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SBGGR10P), { BayerFormat::BGGR, 10, BayerFormat::CSI2Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGBRG10P), { BayerFormat::GBRG, 10, BayerFormat::CSI2Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGRBG10P), { BayerFormat::GRBG, 10, BayerFormat::CSI2Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SRGGB10P), { BayerFormat::RGGB, 10, BayerFormat::CSI2Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_IPU3_SBGGR10), { BayerFormat::BGGR, 10, BayerFormat::IPU3Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_IPU3_SGBRG10), { BayerFormat::GBRG, 10, BayerFormat::IPU3Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_IPU3_SGRBG10), { BayerFormat::GRBG, 10, BayerFormat::IPU3Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_IPU3_SRGGB10), { BayerFormat::RGGB, 10, BayerFormat::IPU3Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SBGGR12), { BayerFormat::BGGR, 12, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGBRG12), { BayerFormat::GBRG, 12, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGRBG12), { BayerFormat::GRBG, 12, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SRGGB12), { BayerFormat::RGGB, 12, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SBGGR12P), { BayerFormat::BGGR, 12, BayerFormat::CSI2Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGBRG12P), { BayerFormat::GBRG, 12, BayerFormat::CSI2Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGRBG12P), { BayerFormat::GRBG, 12, BayerFormat::CSI2Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SRGGB12P), { BayerFormat::RGGB, 12, BayerFormat::CSI2Packed } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SBGGR16), { BayerFormat::BGGR, 16, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGBRG16), { BayerFormat::GBRG, 16, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SGRBG16), { BayerFormat::GRBG, 16, BayerFormat::None } },
>-	{ V4L2PixelFormat(V4L2_PIX_FMT_SRGGB16), { BayerFormat::RGGB, 16, BayerFormat::None } },
>-};
>-
> /* Define a slightly arbitrary ordering so that we can use a std::map. */
> struct BayerFormatComparator {
> 	constexpr bool operator()(const BayerFormat &lhs, const BayerFormat &rhs) const
>@@ -155,20 +125,6 @@ const std::map<BayerFormat, V4L2PixelFormat, BayerFormatComparator> bayerToV4l2{
>  * \param[in] p The type of packing applied to the pixel values
>  */
>
>-/**
>- * \brief Construct a BayerFormat from a V4L2PixelFormat
>- * \param[in] v4l2Format The raw format to convert into a BayerFormat
>- */
>-BayerFormat::BayerFormat(V4L2PixelFormat v4l2Format)
>-	: order(BGGR), packing(None)
>-{
>-	const auto it = v4l2ToBayer.find(v4l2Format);
>-	if (it == v4l2ToBayer.end())
>-		bitDepth = 0;
>-	else
>-		*this = it->second;
>-}
>-
> /**
>  * \fn BayerFormat::isValid()
>  * \brief Return whether a BayerFormat is valid
>@@ -217,6 +173,23 @@ V4L2PixelFormat BayerFormat::toV4L2PixelFormat() const
> 	return V4L2PixelFormat();
> }
>
>+/**
>+ * \brief Convert \a v4l2Format into the corresponding BayerFormat
>+ * \param[in] v4l2Format The raw format to convert into a BayerFormat
>+ * \return The BayerFormat corresponding to \a v4l2Format
>+ */
>+BayerFormat BayerFormat::fromV4L2PixelFormat(V4L2PixelFormat v4l2Format)
>+{
>+	auto it = std::find_if(
>+		bayerToV4l2.begin(),
>+		bayerToV4l2.end(),
>+		[v4l2Format](const auto &i) { return i.second == v4l2Format; });
>+	if (it != bayerToV4l2.end())
>+		return it->first;
>+
>+	return BayerFormat();
>+}
>+
> /**
>  * \brief Apply a transform to this BayerFormat
>  * \param[in] t The transform to apply
>-- 
>2.25.1
>