libcamera: formats: Expose PixelFormatInfo as an internal API

To prepare for storing more information about pixel formats in
PixelFormatInfo, move the class to formats.cpp and document it. The
pixel formats database is moved to the same file, and a new static
function is added to PixelFormatInfo to retrieve a PixelFormatInfo for a
PixelFormat.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

3 files changed, 144 insertions, 72 deletions

diff --git a/src/libcamera/formats.cpp b/src/libcamera/formats.cpp
index 5f6552a4..4a351020 100644
--- a/src/libcamera/formats.cpp
+++ b/src/libcamera/formats.cpp
@@ -9,6 +9,8 @@
 
 #include <errno.h>
 
+#include "log.h"
+
 /**
  * \file formats.h
  * \brief Types and helper methods to handle libcamera image formats
@@ -16,6 +18,8 @@
 
 namespace libcamera {
 
+LOG_DEFINE_CATEGORY(Formats)
+
 /**
  * \class ImageFormats
  * \brief Describe V4L2Device and V4L2SubDevice image formats
@@ -104,4 +108,126 @@ const std::map<unsigned int, std::vector<SizeRange>> &ImageFormats::data() const
 	return data_;
 }
 
+/**
+ * \class PixelFormatInfo
+ * \brief Information about pixel formats
+ *
+ * The PixelFormatInfo class groups together information describing a pixel
+ * format. It facilitates handling of pixel formats by providing data commonly
+ * used in pipeline handlers.
+ *
+ * \var PixelFormatInfo::format
+ * \brief The PixelFormat described by this instance
+ *
+ * \var PixelFormatInfo::v4l2Format
+ * \brief The V4L2 pixel format corresponding to the PixelFormat
+ */
+
+namespace {
+
+const std::map<PixelFormat, PixelFormatInfo> pixelFormatInfo{
+	/* RGB formats. */
+	{ PixelFormat(DRM_FORMAT_BGR888), {
+		.format = PixelFormat(DRM_FORMAT_BGR888),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_RGB24),
+	} },
+	{ PixelFormat(DRM_FORMAT_RGB888), {
+		.format = PixelFormat(DRM_FORMAT_RGB888),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_BGR24),
+	} },
+	{ PixelFormat(DRM_FORMAT_ABGR8888), {
+		.format = PixelFormat(DRM_FORMAT_ABGR8888),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_RGBA32),
+	} },
+	{ PixelFormat(DRM_FORMAT_ARGB8888), {
+		.format = PixelFormat(DRM_FORMAT_ARGB8888),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_ABGR32),
+	} },
+	{ PixelFormat(DRM_FORMAT_BGRA8888), {
+		.format = PixelFormat(DRM_FORMAT_BGRA8888),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_ARGB32),
+	} },
+	{ PixelFormat(DRM_FORMAT_RGBA8888), {
+		.format = PixelFormat(DRM_FORMAT_RGBA8888),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_BGRA32),
+	} },
+
+	/* YUV packed formats. */
+	{ PixelFormat(DRM_FORMAT_YUYV), {
+		.format = PixelFormat(DRM_FORMAT_YUYV),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_YUYV),
+	} },
+	{ PixelFormat(DRM_FORMAT_YVYU), {
+		.format = PixelFormat(DRM_FORMAT_YVYU),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_YVYU),
+	} },
+	{ PixelFormat(DRM_FORMAT_UYVY), {
+		.format = PixelFormat(DRM_FORMAT_UYVY),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_UYVY),
+	} },
+	{ PixelFormat(DRM_FORMAT_VYUY), {
+		.format = PixelFormat(DRM_FORMAT_VYUY),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_VYUY),
+	} },
+
+	/* YUV planar formats. */
+	{ PixelFormat(DRM_FORMAT_NV16), {
+		.format = PixelFormat(DRM_FORMAT_NV16),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_NV16),
+	} },
+	{ PixelFormat(DRM_FORMAT_NV61), {
+		.format = PixelFormat(DRM_FORMAT_NV61),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_NV61),
+	} },
+	{ PixelFormat(DRM_FORMAT_NV12), {
+		.format = PixelFormat(DRM_FORMAT_NV12),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_NV12),
+	} },
+	{ PixelFormat(DRM_FORMAT_NV21), {
+		.format = PixelFormat(DRM_FORMAT_NV21),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_NV21),
+	} },
+
+	/* Greyscale formats. */
+	{ PixelFormat(DRM_FORMAT_R8), {
+		.format = PixelFormat(DRM_FORMAT_R8),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_GREY),
+	} },
+
+	/* Compressed formats. */
+	{ PixelFormat(DRM_FORMAT_MJPEG), {
+		.format = PixelFormat(DRM_FORMAT_MJPEG),
+		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_MJPEG),
+	} },
+};
+
+} /* namespace */
+
+/**
+ * \fn bool PixelFormatInfo::isValid() const
+ * \brief Check if the pixel format info is valid
+ * \return True if the pixel format info is valid, false otherwise
+ */
+
+/**
+ * \brief Retrieve information about a pixel format
+ * \param[in] format The pixel format
+ * \return The PixelFormatInfo describing the \a format if known, or an invalid
+ * PixelFormatInfo otherwise
+ */
+const PixelFormatInfo &PixelFormatInfo::info(const PixelFormat &format)
+{
+	static const PixelFormatInfo invalid{};
+
+	const auto iter = pixelFormatInfo.find(format);
+	if (iter == pixelFormatInfo.end()) {
+		LOG(Formats, Warning)
+			<< "Unsupported pixel format "
+			<< format.toString();
+		return invalid;
+	}
+
+	return iter->second;
+}
+
 } /* namespace libcamera */
diff --git a/src/libcamera/include/formats.h b/src/libcamera/include/formats.h
index f43bc8c0..560df07c 100644
--- a/src/libcamera/include/formats.h
+++ b/src/libcamera/include/formats.h
@@ -12,6 +12,9 @@
 #include <vector>
 
 #include <libcamera/geometry.h>
+#include <libcamera/pixelformats.h>
+
+#include "v4l2_pixelformat.h"
 
 namespace libcamera {
 
@@ -29,6 +32,18 @@ private:
 	std::map<unsigned int, std::vector<SizeRange>> data_;
 };
 
+class PixelFormatInfo
+{
+public:
+	bool isValid() const { return format.isValid(); }
+
+	static const PixelFormatInfo &info(const PixelFormat &format);
+
+	/* \todo Add support for non-contiguous memory planes */
+	PixelFormat format;
+	V4L2PixelFormat v4l2Format;
+};
+
 } /* namespace libcamera */
 
 #endif /* __LIBCAMERA_FORMATS_H__ */
diff --git a/src/libcamera/v4l2_pixelformat.cpp b/src/libcamera/v4l2_pixelformat.cpp
index e1c96b98..580c0fc9 100644
--- a/src/libcamera/v4l2_pixelformat.cpp
+++ b/src/libcamera/v4l2_pixelformat.cpp
@@ -16,6 +16,7 @@
 
 #include <libcamera/pixelformats.h>
 
+#include "formats.h"
 #include "log.h"
 
 /**
@@ -43,71 +44,6 @@ LOG_DECLARE_CATEGORY(V4L2)
 
 namespace {
 
-struct PixelFormatInfo {
-	/* \todo Add support for non-contiguous memory planes */
-	V4L2PixelFormat v4l2Format;
-};
-
-const std::map<PixelFormat, PixelFormatInfo> pf2vpf{
-	/* RGB formats. */
-	{ PixelFormat(DRM_FORMAT_BGR888), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_RGB24),
-	} },
-	{ PixelFormat(DRM_FORMAT_RGB888), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_BGR24),
-	} },
-	{ PixelFormat(DRM_FORMAT_ABGR8888), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_RGBA32),
-	} },
-	{ PixelFormat(DRM_FORMAT_ARGB8888), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_ABGR32),
-	} },
-	{ PixelFormat(DRM_FORMAT_BGRA8888), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_ARGB32),
-	} },
-	{ PixelFormat(DRM_FORMAT_RGBA8888), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_BGRA32),
-	} },
-
-	/* YUV packed formats. */
-	{ PixelFormat(DRM_FORMAT_YUYV), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_YUYV),
-	} },
-	{ PixelFormat(DRM_FORMAT_YVYU), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_YVYU),
-	} },
-	{ PixelFormat(DRM_FORMAT_UYVY), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_UYVY),
-	} },
-	{ PixelFormat(DRM_FORMAT_VYUY), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_VYUY),
-	} },
-
-	/* YUV planar formats. */
-	{ PixelFormat(DRM_FORMAT_NV16), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_NV16),
-	} },
-	{ PixelFormat(DRM_FORMAT_NV61), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_NV61),
-	} },
-	{ PixelFormat(DRM_FORMAT_NV12), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_NV12),
-	} },
-	{ PixelFormat(DRM_FORMAT_NV21), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_NV21),
-	} },
-
-	/* Greyscale formats. */
-	{ PixelFormat(DRM_FORMAT_R8), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_GREY),
-	} },
-
-	/* Compressed formats. */
-	{ PixelFormat(DRM_FORMAT_MJPEG), {
-		.v4l2Format = V4L2PixelFormat(V4L2_PIX_FMT_MJPEG),
-	} },
-};
-
 const std::map<V4L2PixelFormat, PixelFormat> vpf2pf{
 	/* RGB formats. */
 	{ V4L2PixelFormat(V4L2_PIX_FMT_RGB24), PixelFormat(DRM_FORMAT_BGR888) },
@@ -233,15 +169,10 @@ PixelFormat V4L2PixelFormat::toPixelFormat() const
 V4L2PixelFormat V4L2PixelFormat::fromPixelFormat(const PixelFormat &pixelFormat,
 						 bool multiplanar)
 {
-	const auto iter = pf2vpf.find(pixelFormat);
-	if (iter == pf2vpf.end()) {
-		LOG(V4L2, Warning)
-			<< "Unsupported pixel format "
-			<< pixelFormat.toString();
+	const PixelFormatInfo &info = PixelFormatInfo::info(pixelFormat);
+	if (!info.isValid())
 		return V4L2PixelFormat();
-	}
 
-	const PixelFormatInfo &info = iter->second;
 	return info.v4l2Format;
 }