Fix incorrect burnt-in subtitle colours when burning into a DCP source (#2261).

[dcpomatic.git] / src / lib / image.cc

diff --git a/src/lib/image.cc b/src/lib/image.cc
index 7b95e67669ae8ca73ba46bab0aaf8bd7a55a1525..f86c105d4f8aa2d2ab76ce465fd8820d44bfa9bd 100644 (file)
--- a/src/lib/image.cc
+++ b/src/lib/image.cc
@@ -730,14 +730,14 @@ Image::alpha_blend (shared_ptr<const Image> other, Position<int> position)
                                double const b = lut_in[op[blue]];
 
                                /* RGB to XYZ, including Bradford transform and DCI companding */
-                               double const x = max (0.0, min (65535.0, r * fast_matrix[0] + g * fast_matrix[1] + b * fast_matrix[2]));
-                               double const y = max (0.0, min (65535.0, r * fast_matrix[3] + g * fast_matrix[4] + b * fast_matrix[5]));
-                               double const z = max (0.0, min (65535.0, r * fast_matrix[6] + g * fast_matrix[7] + b * fast_matrix[8]));
+                               double const x = max(0.0, min(1.0, r * fast_matrix[0] + g * fast_matrix[1] + b * fast_matrix[2]));
+                               double const y = max(0.0, min(1.0, r * fast_matrix[3] + g * fast_matrix[4] + b * fast_matrix[5]));
+                               double const z = max(0.0, min(1.0, r * fast_matrix[6] + g * fast_matrix[7] + b * fast_matrix[8]));
 
                                /* Out gamma LUT and blend */
-                               tp[0] = lrint(lut_out[lrint(x)] * 65535) * alpha + tp[0] * (1 - alpha);
-                               tp[1] = lrint(lut_out[lrint(y)] * 65535) * alpha + tp[1] * (1 - alpha);
-                               tp[2] = lrint(lut_out[lrint(z)] * 65535) * alpha + tp[2] * (1 - alpha);
+                               tp[0] = lrint(lut_out[lrint(x * 65535)] * 65535) * alpha + tp[0] * (1 - alpha);
+                               tp[1] = lrint(lut_out[lrint(y * 65535)] * 65535) * alpha + tp[1] * (1 - alpha);
+                               tp[2] = lrint(lut_out[lrint(z * 65535)] * 65535) * alpha + tp[2] * (1 - alpha);
 
                                tp += this_bpp / 2;
                                op += other_bpp;