libcamera: software_isp: Move color handling to an algorithm module

After black level handling has been moved to an algorithm module, white
balance and the construction of color tables can be moved to algorithm
modules too.

This time, the moved code is split between stats processing and
parameter construction methods.  It is also split to two algorithm
modules:

- White balance computation.

- Gamma table computation and color lookup tables construction.  While
  this applies the color gains computed by the white balance algorithm,
  it is not directly related to white balance.  And we may want to
  modify the color lookup tables in future according to other parameters
  than just gamma and white balance gains.

Gamma table computation and color lookup tables construction could be
split to separate algorithms too.  But there is no big need for that now
so they are kept together for simplicity.

This is the only part of the software ISP algorithms that sets the
parameters so emitting setIspParams can be moved to prepare() method.

A more natural representation of the gains (and black level) would be
floating point numbers.  This is not done here in order to minimize
changes in code movements.  It will be addressed in a followup patch.

Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Acked-by: Umang Jain <umang.jain@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/src/ipa/simple/ipa_context.cpp b/src/ipa/simple/ipa_context.cpp
index 268cff32..5fa492cb 100644
--- a/src/ipa/simple/ipa_context.cpp
+++ b/src/ipa/simple/ipa_context.cpp
@@ -51,6 +51,11 @@ namespace libcamera::ipa::soft {
  */
 
 /**
+ * \var IPASessionConfiguration::gamma
+ * \brief Gamma value to be used in the raw image processing
+ */
+
+/**
  * \var IPAActiveState::black
  * \brief Context for the Black Level algorithm
  *
@@ -58,4 +63,29 @@ namespace libcamera::ipa::soft {
  * \brief Current determined black level
  */
 
+/**
+ * \var IPAActiveState::gains
+ * \brief Context for gains in the Colors algorithm
+ *
+ * \var IPAActiveState::gains.red
+ * \brief Gain of red color
+ *
+ * \var IPAActiveState::gains.green
+ * \brief Gain of green color
+ *
+ * \var IPAActiveState::gains.blue
+ * \brief Gain of blue color
+ */
+
+/**
+ * \var IPAActiveState::gamma
+ * \brief Context for gamma in the Colors algorithm
+ *
+ * \var IPAActiveState::gamma.gammaTable
+ * \brief Computed gamma table
+ *
+ * \var IPAActiveState::gamma.blackLevel
+ * \brief Black level used for the gamma table computation
+ */
+
 } /* namespace libcamera::ipa::soft */