Merge "ultrahdr icc: update transfer function" (c48c6b1e) · Commits · e / os / platform_frameworks_native

libs/ultrahdr/icc.cpp

+30 −15

Original line number	Diff line number	Diff line
		@@ -19,7 +19,6 @@
		#endif

		#include <ultrahdr/icc.h>
		#include <ultrahdr/gainmapmath.h>
		#include <vector>
		#include <utils/Log.h>

		@@ -227,14 +226,30 @@ sp<DataStruct> IccHelper::write_trc_tag(const int table_entries, const void* tab
		return dataStruct;
		}

		sp<DataStruct> IccHelper::write_trc_tag_for_linear() {
		sp<DataStruct> IccHelper::write_trc_tag(const TransferFunction& fn) {
		if (fn.a == 1.f && fn.b == 0.f && fn.c == 0.f
		&& fn.d == 0.f && fn.e == 0.f && fn.f == 0.f) {
		int total_length = 16;
		sp<DataStruct> dataStruct = sp<DataStruct>::make(total_length);
		sp<DataStruct> dataStruct = new DataStruct(total_length);
		dataStruct->write32(Endian_SwapBE32(kTAG_ParaCurveType)); // Type
		dataStruct->write32(0); // Reserved
		dataStruct->write32(Endian_SwapBE16(kExponential_ParaCurveType));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(1.0)));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.g)));
		return dataStruct;
		}

		int total_length = 40;
		sp<DataStruct> dataStruct = new DataStruct(total_length);
		dataStruct->write32(Endian_SwapBE32(kTAG_ParaCurveType)); // Type
		dataStruct->write32(0); // Reserved
		dataStruct->write32(Endian_SwapBE16(kGABCDEF_ParaCurveType));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.g)));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.a)));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.b)));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.c)));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.d)));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.e)));
		dataStruct->write32(Endian_SwapBE32(float_round_to_fixed(fn.f)));
		return dataStruct;
		}

		@@ -349,7 +364,7 @@ sp<DataStruct> IccHelper::write_mAB_or_mBA_tag(uint32_t type,

		// The "B" curve is required.
		for (size_t i = 0; i < kNumChannels; ++i) {
		b_curves_data[i] = write_trc_tag_for_linear();
		b_curves_data[i] = write_trc_tag(kLinear_TransFun);
		}

		// The "A" curve and CLUT are optional.
		@@ -362,7 +377,7 @@ sp<DataStruct> IccHelper::write_mAB_or_mBA_tag(uint32_t type,

		a_curves_offset = clut_offset + clut->getLength();
		for (size_t i = 0; i < kNumChannels; ++i) {
		a_curves_data[i] = write_trc_tag_for_linear();
		a_curves_data[i] = write_trc_tag(kLinear_TransFun);
		}
		}

		@@ -460,9 +475,9 @@ sp<DataStruct> IccHelper::writeIccProfile(ultrahdr_transfer_function tf,
		tags.emplace_back(kTAG_bTRC,
		write_trc_tag(kTrcTableSize, reinterpret_cast<uint8_t*>(trc_table.data())));
		} else {
		tags.emplace_back(kTAG_rTRC, write_trc_tag_for_linear());
		tags.emplace_back(kTAG_gTRC, write_trc_tag_for_linear());
		tags.emplace_back(kTAG_bTRC, write_trc_tag_for_linear());
		tags.emplace_back(kTAG_rTRC, write_trc_tag(kSRGB_TransFun));
		tags.emplace_back(kTAG_gTRC, write_trc_tag(kSRGB_TransFun));
		tags.emplace_back(kTAG_bTRC, write_trc_tag(kSRGB_TransFun));
		}
		}

libs/ultrahdr/include/ultrahdr/gainmapmath.h

+17 −0

Original line number	Diff line number	Diff line
		@@ -51,6 +51,23 @@ struct Color {
		typedef Color (*ColorTransformFn)(Color);
		typedef float (*ColorCalculationFn)(Color);

		// A transfer function mapping encoded values to linear values,
		// represented by this 7-parameter piecewise function:
		//
		// linear = sign(encoded) * (c*\|encoded\| + f) , 0 <= \|encoded\| < d
		// = sign(encoded) * ((a*\|encoded\| + b)^g + e), d <= \|encoded\|
		//
		// (A simple gamma transfer function sets g to gamma and a to 1.)
		typedef struct TransferFunction {
		float g, a,b,c,d,e,f;
		} TransferFunction;

		static constexpr TransferFunction kSRGB_TransFun =
		{ 2.4f, (float)(1/1.055), (float)(0.055/1.055), (float)(1/12.92), 0.04045f, 0.0f, 0.0f };

		static constexpr TransferFunction kLinear_TransFun =
		{ 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

		inline Color operator+=(Color& lhs, const Color& rhs) {
		lhs.r += rhs.r;
		lhs.g += rhs.g;

libs/ultrahdr/include/ultrahdr/icc.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -17,6 +17,7 @@
		#ifndef ANDROID_ULTRAHDR_ICC_H
		#define ANDROID_ULTRAHDR_ICC_H

		#include <ultrahdr/gainmapmath.h>
		#include <ultrahdr/jpegr.h>
		#include <ultrahdr/jpegrutils.h>
		#include <utils/RefBase.h>
		@@ -222,7 +223,7 @@ private:
		const ultrahdr_color_gamut gamut);
		static sp<DataStruct> write_xyz_tag(float x, float y, float z);
		static sp<DataStruct> write_trc_tag(const int table_entries, const void* table_16);
		static sp<DataStruct> write_trc_tag_for_linear();
		static sp<DataStruct> write_trc_tag(const TransferFunction& fn);
		static float compute_tone_map_gain(const ultrahdr_transfer_function tf, float L);
		static sp<DataStruct> write_cicp_tag(uint32_t color_primaries,
		uint32_t transfer_characteristics);