report: the detector tilt, and the two points the beam centre is not

BEAM_CENTRE is the PONI - the foot of the perpendicular from the sample - so on a
tilted detector it is not where the direct beam lands. The report printed only that
one number and never mentioned the tilt at all, so the two points were
indistinguishable to a reader. On a detector at 85 mm with a 0.22 degree tilt they
are 8.3 px apart.

Print DETECTOR_TILT (rot1/rot2/rot3, degrees, as the run used them - nothing is
refined here) and DIRECT_BEAM beside BEAM_CENTRE, and say which is which.

JFJOCH_DATASET_SETTINGS was the more serious half: it exists to carry a geometry
back into the instrument, and dataset_settings carries poni_rot1/2/3_rad, but the
block omitted them - so it described a FLAT detector, silently, on every tilted
setup. The rotations now ride with it when they are non-zero; they stay out when
they are zero, because the API's own default is 0.0 and the shorter block means the
same thing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EFEJG6WBQv8th4UJFNe53N

docs/CHANGELOG.md

@@ -14,6 +14,7 @@
 * The `rugnux` report gives the strong-direction diffraction limit, and warns when CC1/2 is not monotone with resolution.
 * `rugnux` ranks screw axes on the evidence their absences carry, rather than on how many control reflections a candidate happens to have.
 * Twinning is no longer reported when the L-test contradicts it.
+* The `rugnux` report gives the detector tilt and the direct beam beside the beam centre, and carries the tilt in the `dataset_settings` block.
 * The `jfjoch_viewer` grid scan view draws the cells in the proportion of the scan steps, so the map has the shape of the scanned area.
 
 ### 1.0.0-rc.165

rugnux/ResultReport.cpp

@@ -91,9 +91,25 @@ std::string RenderResultReport(const std::string &output_prefix,
     }
     Key(os, "DETECTOR_DISTANCE", fmt::format("{:.3f}", result.used_distance_mm));
     Key(os, "BEAM_CENTRE", fmt::format("{:.2f} {:.2f}", result.used_beam_x_pxl, result.used_beam_y_pxl));
+    // The tilt this run integrated at, and the two points it separates. BEAM_CENTRE is the PONI - the
+    // foot of the perpendicular from the sample - so on a tilted detector it is NOT where the direct
+    // beam lands, and the two were previously indistinguishable in this report because only one of
+    // them was printed. Degrees here; the JSON below carries radians, as the API spells it.
+    {
+        const auto &g = experiment.GetDiffractionGeometry();
+        constexpr double DEG = 180.0 / M_PI;
+        const auto direct = g.GetDirectBeam_pxl();
+        Key(os, "DETECTOR_TILT", fmt::format("{:.4f} {:.4f} {:.4f}", g.GetPoniRot1_rad() * DEG,
+                                             g.GetPoniRot2_rad() * DEG, g.GetPoniRot3_rad() * DEG));
+        Key(os, "DIRECT_BEAM", fmt::format("{:.2f} {:.2f}", direct.first, direct.second));
+    }
     os << "\n"
        << " The distance and beam centre above are the ones this result was integrated at, which on\n"
-       << " a rotation run is the post-refined geometry rather than the values in the input file.\n";
+       << " a rotation run is the post-refined geometry rather than the values in the input file.\n"
+       << " DETECTOR_TILT is rot1/rot2/rot3 in degrees, as the run used them - it is not refined here.\n"
+       << " BEAM_CENTRE is the PONI and DIRECT_BEAM is where the beam actually lands; they differ by\n"
+       << " distance*tan(tilt)/pixel and are identical only when the tilt is zero. Quote whichever the\n"
+       << " program you are feeding expects, and check which one it means.\n";
 
     // The same geometry once more, as the object jfjoch_broker takes it in: the four required
     // properties of dataset_settings in broker/jfjoch_api.yaml, spelled the way the API spells them.
@@ -101,14 +117,27 @@ std::string RenderResultReport(const std::string &output_prefix,
     // this the only way back into the instrument is to read two numbers off this report by eye and
     // retype them. One line, valid JSON, so a script can lift it with a grep and POST it.
     os << "\n";
-    Key(os, "JFJOCH_DATASET_SETTINGS",
-        fmt::format(R"({{"beam_x_pxl": {:.2f}, "beam_y_pxl": {:.2f}, "detector_distance_mm": {:.3f}, )"
-                    R"("incident_energy_keV": {:.4f}}})",
-                    result.used_beam_x_pxl, result.used_beam_y_pxl, result.used_distance_mm,
-                    experiment.GetDatasetSettings().GetPhotonEnergy_keV()));
+    {
+        // The rotations belong here whenever they are not zero: dataset_settings carries
+        // poni_rot1/2/3_rad, and a block that omits them describes a FLAT detector - a different
+        // geometry from the one this run used, silently, on every tilted setup. Omitted when zero
+        // because the API's own default is 0.0, so the shorter block means the same thing.
+        const auto &g = experiment.GetDiffractionGeometry();
+        std::string rot;
+        if (g.GetPoniRot1_rad() != 0.0f || g.GetPoniRot2_rad() != 0.0f || g.GetPoniRot3_rad() != 0.0f)
+            rot = fmt::format(R"(, "poni_rot1_rad": {:.6f}, "poni_rot2_rad": {:.6f}, )"
+                              R"("poni_rot3_rad": {:.6f})",
+                              g.GetPoniRot1_rad(), g.GetPoniRot2_rad(), g.GetPoniRot3_rad());
+        Key(os, "JFJOCH_DATASET_SETTINGS",
+            fmt::format(R"({{"beam_x_pxl": {:.2f}, "beam_y_pxl": {:.2f}, "detector_distance_mm": {:.3f}, )"
+                        R"("incident_energy_keV": {:.4f}{}}})",
+                        result.used_beam_x_pxl, result.used_beam_y_pxl, result.used_distance_mm,
+                        experiment.GetDatasetSettings().GetPhotonEnergy_keV(), rot));
+    }
     os << "\n"
        << " The geometry above as jfjoch_broker's dataset_settings, to carry a refined beam centre and\n"
-       << " distance back to the instrument for the next collection.\n";
+       << " distance back to the instrument for the next collection. The PONI rotations ride with it\n"
+       << " when they are non-zero, because without them the block describes a flat detector.\n";
 
     if (result.spot_resolution_estimate_A.has_value()) {
         os << "\n";