libipa: awb: Make result of gainsFromColourTemp optional

In the grey world AWB case, if no colour gains are contained in the
tuning file, the colour gains get reset to 1 when the colour temperature
is set manually. This is unexpected and undesirable. Allow the
gainsFromColourTemp() function to return a std::nullopt to handle that
case.

While at it, remove an unnecessary import from rkisp1/algorithms/awb.h.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/ipa/libipa/awb_grey.cpp b/src/ipa/libipa/awb_grey.cpp
index d3d2132b..d252edb2 100644
--- a/src/ipa/libipa/awb_grey.cpp
+++ b/src/ipa/libipa/awb_grey.cpp
@@ -98,15 +98,15 @@ AwbResult AwbGrey::calculateAwb(const AwbStats &stats, [[maybe_unused]] unsigned
  * \return The colour gains if a colour temperature curve is available,
  * [1, 1, 1] otherwise.
  */
-RGB<double> AwbGrey::gainsFromColourTemperature(double colourTemperature)
+std::optional<RGB<double>> AwbGrey::gainsFromColourTemperature(double colourTemperature)
 {
 	if (!colourGainCurve_) {
 		LOG(Awb, Error) << "No gains defined";
-		return RGB<double>({ 1.0, 1.0, 1.0 });
+		return std::nullopt;
 	}
 
 	auto gains = colourGainCurve_->getInterpolated(colourTemperature);
-	return { { gains[0], 1.0, gains[1] } };
+	return RGB<double>{ { gains[0], 1.0, gains[1] } };
 }
 
 } /* namespace ipa */