Various fixes to XYZ/RGB transforms.

4 files changed, 143 insertions, 13 deletions

diff --git a/test/colour_conversion_test.cc b/test/colour_conversion_test.cc
index 060148a6..aafd2cad 100644
--- a/test/colour_conversion_test.cc
+++ b/test/colour_conversion_test.cc
@@ -30,22 +30,22 @@ using namespace dcp;
 static void
 check_gamma (shared_ptr<const TransferFunction> tf, int bit_depth, float gamma)
 {
-	float const * lut = tf->lut (bit_depth);
+	double const * lut = tf->lut (bit_depth);
 	int const count = pow (2, bit_depth);
 
 	for (int i = 0; i < count; ++i) {
-		BOOST_CHECK_CLOSE (lut[i], pow (float(i) / (count - 1), gamma), 0.001);
+		BOOST_CHECK_CLOSE (lut[i], pow (double(i) / (count - 1), gamma), 0.001);
 	}
 }
 
 static void
-check_modified_gamma (shared_ptr<const TransferFunction> tf, int bit_depth, float power, float threshold, float A, float B)
+check_modified_gamma (shared_ptr<const TransferFunction> tf, int bit_depth, double power, double threshold, double A, double B)
 {
-	float const * lut = tf->lut (bit_depth);
+	double const * lut = tf->lut (bit_depth);
 	int const count = pow (2, bit_depth);
 
 	for (int i = 0; i < count; ++i) {
-		float const x = float(i) / (count - 1);
+		double const x = double(i) / (count - 1);
 		if (x > threshold) {
 			BOOST_CHECK_CLOSE (lut[i], pow ((x + A) / (1 + A), power), 0.001);
 		} else {
@@ -62,9 +62,9 @@ BOOST_AUTO_TEST_CASE (colour_conversion_test1)
 	check_modified_gamma (cc.in(), 12, 2.4, 0.04045, 0.055, 12.92);
 	check_modified_gamma (cc.in(), 16, 2.4, 0.04045, 0.055, 12.92);
 
-	check_gamma (cc.out(), 8, 2.6);
-	check_gamma (cc.out(), 12, 2.6);
-	check_gamma (cc.out(), 16, 2.6);
+	check_gamma (cc.out(), 8, 1 / 2.6);
+	check_gamma (cc.out(), 12, 1 / 2.6);
+	check_gamma (cc.out(), 16, 1 / 2.6);
 }
 
 BOOST_AUTO_TEST_CASE (colour_conversion_test2)
@@ -75,8 +75,8 @@ BOOST_AUTO_TEST_CASE (colour_conversion_test2)
 	check_modified_gamma (cc.in(), 12, 2.4, 0.081, 0.099, 4.5);
 	check_modified_gamma (cc.in(), 16, 2.4, 0.081, 0.099, 4.5);
 
-	check_gamma (cc.out(), 8, 2.6);
-	check_gamma (cc.out(), 12, 2.6);
-	check_gamma (cc.out(), 16, 2.6);
+	check_gamma (cc.out(), 8, 1 / 2.6);
+	check_gamma (cc.out(), 12, 1 / 2.6);
+	check_gamma (cc.out(), 16, 1 / 2.6);
 }
 
diff --git a/test/image_test.cc b/test/image_test.cc
index 26f27499..6b024c1a 100644
--- a/test/image_test.cc
+++ b/test/image_test.cc
@@ -44,11 +44,11 @@ public:
 
 	}
 
-	uint8_t** data () const {
+	uint16_t * const * data () const {
 		return 0;
 	}
 
-	int* stride () const {
+	int const * stride () const {
 		return 0;
 	}
 };
diff --git a/test/rgb_xyz_test.cc b/test/rgb_xyz_test.cc
new file mode 100644
index 00000000..b33a0f4a
--- /dev/null
+++ b/test/rgb_xyz_test.cc
@@ -0,0 +1,129 @@
+/*
+    Copyright (C) 2014 Carl Hetherington <cth@carlh.net>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include "image.h"
+#include "rgb_xyz.h"
+#include "xyz_frame.h"
+#include "colour_conversion.h"
+#include <boost/test/unit_test.hpp>
+
+using std::max;
+using boost::shared_ptr;
+
+class SimpleImage : public dcp::Image
+{
+public:
+	SimpleImage (dcp::Size size)
+		: Image (size)
+	{
+		/* 48bpp */
+		_stride[0] = _size.width * 6;
+		_data[0] = new uint16_t[size.height * stride()[0] / 2];
+	}
+
+	~SimpleImage ()
+	{
+		delete[] _data[0];
+	}
+
+	uint16_t * const * data () const {
+		return _data;
+	}
+
+	int const * stride () const {
+		return _stride;
+	}
+
+private:
+	uint16_t* _data[1];
+	int _stride[1];
+};
+
+/** Convert a test image from sRGB to XYZ and check that the transforms are right */
+BOOST_AUTO_TEST_CASE (rgb_xyz_test)
+{
+	unsigned int seed = 0;
+	dcp::Size const size (640, 480);
+
+	shared_ptr<const dcp::Image> rgb (new SimpleImage (size));
+	for (int y = 0; y < size.height; ++y) {
+		uint16_t* p = rgb->data()[0] + y * rgb->stride()[0] / 2;
+		for (int x = 0; x < size.width; ++x) {
+			/* Write a 12-bit random number for each component */
+			for (int c = 0; c < 3; ++c) {
+				*p = (rand_r (&seed) & 0xfff) << 4;
+				++p;
+			}
+		}
+	}
+
+	shared_ptr<dcp::XYZFrame> xyz = dcp::rgb_to_xyz (rgb, dcp::ColourConversion::srgb_to_xyz);
+
+	for (int y = 0; y < size.height; ++y) {
+		uint16_t* p = rgb->data()[0] + y * rgb->stride()[0] / 2;
+		for (int x = 0; x < size.width; ++x) {
+
+			double cr = *p++ / 65535.0;
+			double cg = *p++ / 65535.0;
+			double cb = *p++ / 65535.0;
+
+			/* Input gamma */
+
+			if (cr < 0.04045) {
+				cr /= 12.92;
+			} else {
+				cr = pow ((cr + 0.055) / 1.055, 2.4);
+			}
+
+			if (cg < 0.04045) {
+				cg /= 12.92;
+			} else {
+				cg = pow ((cg + 0.055) / 1.055, 2.4);
+			}
+
+			if (cb < 0.04045) {
+				cb /= 12.92;
+			} else {
+				cb = pow ((cb + 0.055) / 1.055, 2.4);
+			}
+
+			/* Matrix */
+
+			double cx = cr * 0.4124564 + cg * 0.3575761 + cb * 0.1804375;
+			double cy = cr * 0.2126729 + cg * 0.7151522 + cb * 0.0721750;
+			double cz = cr * 0.0193339 + cg * 0.1191920 + cb * 0.9503041;
+
+			/* Compand */
+
+			cx *= 48 / 52.37;
+			cy *= 48 / 52.37;
+			cz *= 48 / 52.37;
+
+			/* Output gamma */
+
+			cx = pow (cx, 1 / 2.6);
+			cy = pow (cy, 1 / 2.6);
+			cz = pow (cz, 1 / 2.6);
+
+			BOOST_REQUIRE_CLOSE (cx * 4095, xyz->data(0)[y * size.width + x], 1);
+			BOOST_REQUIRE_CLOSE (cy * 4095, xyz->data(1)[y * size.width + x], 1);
+			BOOST_REQUIRE_CLOSE (cz * 4095, xyz->data(2)[y * size.width + x], 1);
+		}
+	}
+}
diff --git a/test/wscript b/test/wscript
index c19d2533..1208dd0e 100644
--- a/test/wscript
+++ b/test/wscript
@@ -44,6 +44,7 @@ def build(bld):
                  kdm_test.cc
                  read_dcp_test.cc
                  recovery_test.cc
+                 rgb_xyz_test.cc
                  round_trip_test.cc
                  smpte_load_font_test.cc
                  subtitle_test.cc