Move XYZ/RGB function to its own source file.

1 files changed, 109 insertions, 0 deletions

diff --git a/src/rgb_xyz.cc b/src/rgb_xyz.cc
new file mode 100644
index 00000000..6be7180f
--- /dev/null
+++ b/src/rgb_xyz.cc
@@ -0,0 +1,109 @@
+/*
+    Copyright (C) 2013 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 "rgb_xyz.h"
+#include "argb_frame.h"
+#include "xyz_frame.h"
+#include "gamma_lut.h"
+
+using std::min;
+using std::max;
+using boost::shared_ptr;
+using namespace libdcp;
+
+/** Convert an openjpeg XYZ image to RGB.
+ *  @param xyz_frame Frame in XYZ.
+ *  @return RGB image.
+ */
+shared_ptr<ARGBFrame>
+libdcp::xyz_to_rgb (shared_ptr<const XYZFrame> xyz_frame, shared_ptr<const GammaLUT> lut_in, shared_ptr<const GammaLUT> lut_out)
+{
+	float const dci_coefficient = 48.0 / 52.37;
+
+        /* sRGB color matrix for XYZ -> RGB.  This is the same as the one used by the Fraunhofer
+	   EasyDCP player, I think.
+	*/
+
+	float const colour_matrix[3][3] = {
+		{  3.24096989631653,   -1.5373831987381,  -0.498610764741898 },
+		{ -0.96924364566803,    1.87596750259399,  0.0415550582110882 },
+		{  0.0556300804018974, -0.203976958990097, 1.05697154998779 }
+	};
+
+	int const max_colour = pow (2, lut_out->bit_depth()) - 1;
+
+	struct {
+		double x, y, z;
+	} s;
+	
+	struct {
+		double r, g, b;
+	} d;
+	
+	int* xyz_x = xyz_frame->data (0);
+	int* xyz_y = xyz_frame->data (1);
+	int* xyz_z = xyz_frame->data (2);
+
+	shared_ptr<ARGBFrame> argb_frame (new ARGBFrame (xyz_frame->size ()));
+
+	uint8_t* argb = argb_frame->data ();
+	
+	for (int y = 0; y < xyz_frame->size().height; ++y) {
+		uint8_t* argb_line = argb;
+		for (int x = 0; x < xyz_frame->size().width; ++x) {
+
+			assert (*xyz_x >= 0 && *xyz_y >= 0 && *xyz_z >= 0 && *xyz_x < 4096 && *xyz_x < 4096 && *xyz_z < 4096);
+			
+			/* In gamma LUT */
+			s.x = lut_in->lut()[*xyz_x++];
+			s.y = lut_in->lut()[*xyz_y++];
+			s.z = lut_in->lut()[*xyz_z++];
+
+			/* DCI companding */
+			s.x /= dci_coefficient;
+			s.y /= dci_coefficient;
+			s.z /= dci_coefficient;
+			
+			/* XYZ to RGB */
+			d.r = ((s.x * colour_matrix[0][0]) + (s.y * colour_matrix[0][1]) + (s.z * colour_matrix[0][2]));
+			d.g = ((s.x * colour_matrix[1][0]) + (s.y * colour_matrix[1][1]) + (s.z * colour_matrix[1][2]));
+			d.b = ((s.x * colour_matrix[2][0]) + (s.y * colour_matrix[2][1]) + (s.z * colour_matrix[2][2]));
+			
+			d.r = min (d.r, 1.0);
+			d.r = max (d.r, 0.0);
+			
+			d.g = min (d.g, 1.0);
+			d.g = max (d.g, 0.0);
+			
+			d.b = min (d.b, 1.0);
+			d.b = max (d.b, 0.0);
+			
+			/* Out gamma LUT */
+			*argb_line++ = lut_out->lut()[(int) (d.b * max_colour)] * 0xff;
+			*argb_line++ = lut_out->lut()[(int) (d.g * max_colour)] * 0xff;
+			*argb_line++ = lut_out->lut()[(int) (d.r * max_colour)] * 0xff;
+			*argb_line++ = 0xff;
+		}
+		
+		argb += argb_frame->stride ();
+	}
+
+	return argb_frame;
+}
+