libcamera: camera: Add validateColorSpaces to CameraConfiguration class

This function forces raw streams to have the "raw" color space, and
also optionally makes all non-raw output streams to share the same
color space as some platforms may require this.

When sharing color spaces we take the shared value to be the one from
the largest of these streams. This choice is ultimately arbitrary, but
can be appropriate if smaller output streams are used for image
analysis rather than human consumption, when the precise colours may
be less important.

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

include/libcamera/camera.h

@@ -13,6 +13,7 @@
 #include <string>
 
 #include <libcamera/base/class.h>
+#include <libcamera/base/flags.h>
 #include <libcamera/base/object.h>
 #include <libcamera/base/signal.h>
 
@@ -69,6 +70,15 @@ public:
 protected:
 	CameraConfiguration();
 
+	enum class ColorSpaceFlag {
+		None,
+		StreamsShareColorSpace,
+	};
+
+	using ColorSpaceFlags = Flags<ColorSpaceFlag>;
+
+	Status validateColorSpaces(ColorSpaceFlags flags = ColorSpaceFlag::None);
+
 	std::vector<StreamConfiguration> config_;
 };