From d17e8d1654f5895a05e3d68f36b14946eafffb39 Mon Sep 17 00:00:00 2001
From: Nico Weber <thakis@chromium.org>
Date: Wed, 6 Dec 2023 19:58:34 -0500
Subject: [PATCH] LibGfx/ICC: Plumb mBA conversion from profile to tag data

It's still implemented on the tag data side, so no real
behavior change.
---
 Userland/Libraries/LibGfx/ICC/Profile.cpp | 15 +++++++++++----
 Userland/Libraries/LibGfx/ICC/TagTypes.h  | 12 ++++++++++++
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/Userland/Libraries/LibGfx/ICC/Profile.cpp b/Userland/Libraries/LibGfx/ICC/Profile.cpp
index f96ba6067c..9d51d404ef 100644
--- a/Userland/Libraries/LibGfx/ICC/Profile.cpp
+++ b/Userland/Libraries/LibGfx/ICC/Profile.cpp
@@ -1416,7 +1416,7 @@ static TagSignature backward_transform_tag_for_rendering_intent(RenderingIntent
     VERIFY_NOT_REACHED();
 }
 
-ErrorOr<void> Profile::from_pcs_b_to_a(TagData const& tag_data, FloatVector3 const&, Bytes) const
+ErrorOr<void> Profile::from_pcs_b_to_a(TagData const& tag_data, FloatVector3 const& pcs, Bytes out_bytes) const
 {
     switch (tag_data.type()) {
     case Lut16TagData::Type:
@@ -1425,9 +1425,16 @@ ErrorOr<void> Profile::from_pcs_b_to_a(TagData const& tag_data, FloatVector3 con
     case Lut8TagData::Type:
         // FIXME
         return Error::from_string_literal("ICC::Profile::to_pcs: BToA*Tag handling for mft1 tags not yet implemented");
-    case LutBToATagData::Type:
-        // FIXME
-        return Error::from_string_literal("ICC::Profile::to_pcs: BToA*Tag handling for mBA tags not yet implemented");
+    case LutBToATagData::Type: {
+        auto const& b_to_a = static_cast<LutBToATagData const&>(tag_data);
+        if (b_to_a.number_of_input_channels() != number_of_components_in_color_space(connection_space()))
+            return Error::from_string_literal("ICC::Profile::from_pcs_b_to_a: mBA input channel count does not match color space size");
+
+        if (b_to_a.number_of_output_channels() != number_of_components_in_color_space(data_color_space()))
+            return Error::from_string_literal("ICC::Profile::from_pcs_b_to_a: mBA output channel count does not match profile connection space size");
+
+        return b_to_a.evaluate(connection_space(), pcs, out_bytes);
+    }
     }
     VERIFY_NOT_REACHED();
 }
diff --git a/Userland/Libraries/LibGfx/ICC/TagTypes.h b/Userland/Libraries/LibGfx/ICC/TagTypes.h
index 2e9cbf7e78..6ac231195a 100644
--- a/Userland/Libraries/LibGfx/ICC/TagTypes.h
+++ b/Userland/Libraries/LibGfx/ICC/TagTypes.h
@@ -519,6 +519,9 @@ public:
     Optional<CLUTData> const& clut() const { return m_clut; }
     Optional<Vector<LutCurveType>> const& a_curves() const { return m_a_curves; }
 
+    // Returns the result of the LUT pipeline for u8 outputs.
+    ErrorOr<void> evaluate(ColorSpace connection_space, FloatVector3 const&, Bytes) const;
+
 private:
     u8 m_number_of_input_channels;
     u8 m_number_of_output_channels;
@@ -1300,6 +1303,15 @@ inline ErrorOr<FloatVector3> LutAToBTagData::evaluate(ColorSpace connection_spac
     return output_color;
 }
 
+inline ErrorOr<void> LutBToATagData::evaluate(ColorSpace connection_space, FloatVector3 const&, Bytes out_bytes) const
+{
+    VERIFY(connection_space == ColorSpace::PCSXYZ || connection_space == ColorSpace::PCSLAB);
+    VERIFY(number_of_input_channels() == 3);
+    VERIFY(number_of_output_channels() == out_bytes.size());
+
+    return Error::from_string_literal("LutBToATagData::evaluate: Not yet implemented");
+}
+
 }
 
 template<>