[libcamera-devel] [PATCH] libcamera: PixelFormat: Define a FourCC output helper

[Kieran Bingham]

Provide a helper to print the FourCC string representation, and utilise
it to improve the readability of the StreamConfiguration.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
This changes the output of the line:
[159:34:26.262068766] [16497] INFO Camera camera.cpp:784 configuring streams: (0) 1920x1080-0x47504a4d

to read:
[159:34:26.262068766] [16497] INFO Camera camera.cpp:784 configuring streams: (0) 1920x1080-0x47504a4d MJPG

 include/libcamera/pixelformats.h |  3 +++
 src/libcamera/pixelformats.cpp   | 20 ++++++++++++++++++++
 src/libcamera/stream.cpp         |  3 ++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/include/libcamera/pixelformats.h b/include/libcamera/pixelformats.h
index 6e25b8d8b76e..32cff083cdf9 100644
--- a/include/libcamera/pixelformats.h
+++ b/include/libcamera/pixelformats.h
@@ -8,11 +8,14 @@
 #define __LIBCAMERA_PIXEL_FORMATS_H__
 
 #include <stdint.h>
+#include <string>
 
 namespace libcamera {
 
 using PixelFormat = uint32_t;
 
+std::string FourCC(const PixelFormat &p);
+
 } /* namespace libcamera */
 
 #endif /* __LIBCAMERA_PIXEL_FORMATS_H__ */
diff --git a/src/libcamera/pixelformats.cpp b/src/libcamera/pixelformats.cpp
index c03335400b70..d6b2c6a3dba5 100644
--- a/src/libcamera/pixelformats.cpp
+++ b/src/libcamera/pixelformats.cpp
@@ -7,6 +7,8 @@
 
 #include <libcamera/pixelformats.h>
 
+#include <sstream>
+
 /**
  * \file pixelformats.h
  * \brief libcamera pixel formats
@@ -25,4 +27,22 @@ namespace libcamera {
  * \todo Add support for format modifiers
  */
 
+/**
+ * \brief Return a PixelFormat as a FourCC string representation
+ */
+std::string FourCC(const PixelFormat &p)
+{
+	std::stringstream ss;
+
+	ss << static_cast<char>(p & 0x7f)
+	   << static_cast<char>((p >> 8) & 0x7f)
+	   << static_cast<char>((p >> 16) & 0x7f)
+	   << static_cast<char>((p >> 24) & 0x7f);
+
+	if (p & (1 << 31))
+		ss << "-BE";
+
+	return ss.str();
+}
+
 } /* namespace libcamera */
diff --git a/src/libcamera/stream.cpp b/src/libcamera/stream.cpp
index 13789e9eb344..4efe4385326f 100644
--- a/src/libcamera/stream.cpp
+++ b/src/libcamera/stream.cpp
@@ -348,7 +348,8 @@ StreamConfiguration::StreamConfiguration(const StreamFormats &formats)
 std::string StreamConfiguration::toString() const
 {
 	std::stringstream ss;
-	ss << size.toString() << "-" << utils::hex(pixelFormat);
+	ss << size.toString() << "-" << utils::hex(pixelFormat)
+	   << " " << FourCC(pixelFormat);
 	return ss.str();
 }
 
-- 
2.20.1