v1.0.0-rc.166 (#76)

* `rugnux --mode calibration` writes `<prefix>.json` beside the `.poni`, whose `dataset_settings` member is a `jfjoch_broker` `dataset_settings` body as it stands.
* `rugnux` and `jfjoch_viewer` read PILATUS miniCBF sweeps natively, without conversion.
* Masters written by other facilities open, including Eiger 1.x and third-party NXmx variants.
* `rugnux` measures the beam centre on every run, and indexes with it when the file's value indexes nothing.
* A detector swung out on a 2theta arm is placed where the file says it stands, and the calibration can hold the tilt fixed.
* `rugnux` writes the unmerged MTZ by default, and a P1 merge beside it, so a wrong space group can be re-merged without reprocessing.
* Significant improvements to symmetry handling in `rugnux`: the lattice, the point group, the setting and the systematic absences.
* The `rugnux` report gives the resolution the CC1/2 fit reached, beside the range the reflections were written to.
* The `rugnux` report gives the twinning statistics measured before the space group was decided, beside the ones measured after.
* 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, the measured tilt and the direct beam beside the beam centre, and a post-refined beam centre is judged against the run's own measurement rather than the file's.
* `--no-refine-tilt` holds the detector tilt at the value in the file, instead of zeroing it, when the calibration starts from the spots.
* 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.

Reviewed-on: #76
Co-authored-by: Filip Leonarski <filip.leonarski@psi.ch>

common/DetectorOrientation.cpp

@@ -0,0 +1,63 @@
+// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
+// SPDX-License-Identifier: GPL-3.0-only
+
+#include "DetectorOrientation.h"
+#include "JFJochException.h"
+
+DetectorOrientation::DetectorOrientation(bool mirror_y, int64_t quarter_turns) {
+    MirrorY(mirror_y);
+    QuarterTurns(quarter_turns);
+}
+
+DetectorOrientation &DetectorOrientation::MirrorY(bool input) {
+    mirror_y = input;
+    return *this;
+}
+
+DetectorOrientation &DetectorOrientation::QuarterTurns(int64_t input) {
+    if ((input < 0) || (input > 3))
+        throw JFJochException(JFJochExceptionCategory::InputParameterInvalid,
+                              "Quarter turns must be 0, 1, 2 or 3");
+    quarter_turns = input;
+    return *this;
+}
+
+bool DetectorOrientation::IsMirrorY() const {
+    return mirror_y;
+}
+
+int64_t DetectorOrientation::GetQuarterTurns() const {
+    return quarter_turns;
+}
+
+bool DetectorOrientation::IsIdentity() const {
+    return !mirror_y && (quarter_turns == 0);
+}
+
+RotMatrix DetectorOrientation::Matrix() const {
+    // Columns of Rz(k*90 deg), in the internal frame (x = column, y = row downward, z = beam). y
+    // points down, so a positive right-handed turn about +z takes +x to +y - clockwise on screen.
+    const float c[4] = {1, 0, -1, 0};
+    const float s[4] = {0, 1, 0, -1};
+    const Coord rz_x = {c[quarter_turns], s[quarter_turns], 0};
+    const Coord rz_y = {-s[quarter_turns], c[quarter_turns], 0};
+
+    // Rz * diag(1,-1,1): the mirror negates the second column.
+    return {rz_x, mirror_y ? -rz_y : rz_y, {0, 0, 1}};
+}
+
+std::optional<DetectorOrientation> DetectorOrientation::Match(const Coord &fast, const Coord &slow) {
+    for (int64_t quarter_turns = 0; quarter_turns < 4; quarter_turns++) {
+        for (const bool mirror_y: {false, true}) {
+            const DetectorOrientation orientation(mirror_y, quarter_turns);
+            const RotMatrix m = orientation.Matrix();
+            if (((m.Column(0) - fast).Length() < 1e-3f) && ((m.Column(1) - slow).Length() < 1e-3f))
+                return orientation;
+        }
+    }
+    return {};
+}
+
+bool DetectorOrientation::operator==(const DetectorOrientation &other) const {
+    return (mirror_y == other.mirror_y) && (quarter_turns == other.quarter_turns);
+}