Port batch image export onto the sras_viewer package split

origin/main split sras_viewer.py into the sras_viewer/ package (dialogs,
main_window, common, canvases) after the batch-export feature was built
against the old monolith, so merging origin/main into main lost the feature
to the sras_viewer.py deletion. Re-add it in the new structure:
BatchExportDialog in dialogs.py, a Jobs.EXPORT job key in common.py, and
the menu action/worker wiring in main_window.py, following the Jobs-key
and dialog-class conventions the split already established rather than the
old ad hoc "main" progress-key naming the original commit used.

Also carries forward two test fixes bundled in the original batch-export
commit that the parallel pytest conversion (007089d) had ported from
tools/test_refactor.py without them: the int16-vs-float32 accumulator
expectation in test_sras_average, and asserting the sras_average.py
subprocess calls actually succeed.

sras_viewer/common.py

@@ -60,6 +60,7 @@ class Jobs:
     COMPUTE = "compute"
     DC_PRECOMPUTE = "dc_precompute"
     BATCH = "batch"
+    EXPORT = "export"
     # The alignment wizard's three background steps: fetching each angle's CH4
     # image for the mask stack, registering the angles, and writing the aligned
     # export. Separate keys because a retry of one must not be blocked by

sras_viewer/dialogs.py

@@ -8,15 +8,20 @@ mask-overlay editor plus the crop and export steps.
 from pathlib import Path
 
 from PyQt6.QtWidgets import (
-    QButtonGroup, QCheckBox, QDialog, QDialogButtonBox, QFileDialog,
+    QButtonGroup, QCheckBox, QDialog, QDialogButtonBox, QDoubleSpinBox,
-    QGroupBox, QHBoxLayout, QLabel, QLineEdit, QPushButton, QRadioButton,
+    QFileDialog, QGridLayout, QGroupBox, QHBoxLayout, QLabel, QLineEdit,
-    QScrollArea, QSpinBox, QVBoxLayout, QWidget,
+    QMessageBox, QPushButton, QRadioButton, QScrollArea, QSpinBox,
+    QVBoxLayout, QWidget,
 )
 
 from sras_compute import PYFFTW_AVAILABLE
 from sras_format import CH1_IDX, CH3_IDX, CH4_IDX, CH_NAMES
+from sras_workers import ExportChannel
 
-from .common import CH_LABELS, VELOCITY_MODE_IDX, _CSS_HINT, _CSS_WARN, _group, _make_dspin, _wrap_label
+from .common import (
+    CH_LABELS, VELOCITY_MODE_IDX, _CHANNEL_DISPLAY, _CSS_HINT, _CSS_WARN,
+    _SPIN_MIN_W, _form, _group, _make_dspin, _wrap_label,
+)
 
 
 # ---------------------------------------------------------------------------
@@ -240,6 +245,137 @@ class RowAverageFftOptionsDialog(QDialog):
         return self._spin_threshold.value()
 
 
+# ---------------------------------------------------------------------------
+# Batch export dialog (Export -> Batch Export Images...)
+# ---------------------------------------------------------------------------
+
+class BatchExportDialog(QDialog):
+    """Configure a batch PNG export of DC/RF/Velocity maps across every angle
+    of the currently open file.
+
+    Each channel's colorbar range is entered here and held fixed for every
+    exported angle (rather than auto-scaled per image, today's live-view
+    default) so the exported images are directly comparable to each other.
+    """
+
+    # (ch_idx, is_velocity, label, colorbar unit, filename tag)
+    _ROWS = [
+        (CH1_IDX, False, CH_LABELS[CH1_IDX], _CHANNEL_DISPLAY[CH1_IDX][2],
+         CH_NAMES[CH1_IDX]),
+        (CH3_IDX, False, CH_LABELS[CH3_IDX], _CHANNEL_DISPLAY[CH3_IDX][2],
+         CH_NAMES[CH3_IDX]),
+        (CH4_IDX, False, CH_LABELS[CH4_IDX], _CHANNEL_DISPLAY[CH4_IDX][2],
+         CH_NAMES[CH4_IDX]),
+        (CH1_IDX, True, CH_LABELS[VELOCITY_MODE_IDX],
+         _CHANNEL_DISPLAY[VELOCITY_MODE_IDX][2], CH_NAMES[VELOCITY_MODE_IDX]),
+    ]
+    # DC is cheap and precomputed on load; CH1/Velocity need a per-pixel FFT
+    # that can take minutes, so don't default to exporting them (same
+    # rationale as SrasViewerWindow._on_load_done's channel default).
+    _DEFAULT_CHECKED = {CH3_IDX, CH4_IDX}
+
+    def __init__(self, parent, *, default_dir: str, default_prefix: str,
+                 default_ranges: dict[tuple[int, bool], tuple[float, float]]):
+        super().__init__(parent)
+        self.setWindowTitle("Batch Export Images")
+        self.setModal(True)
+        self.setMinimumWidth(460)
+
+        layout = QVBoxLayout(self)
+
+        # ---- Output ------------------------------------------------------
+        grp_out, ol = _group("Output")
+        dir_row = QHBoxLayout()
+        self._edit_dir = QLineEdit(default_dir)
+        btn_browse = QPushButton("Browse…")
+        btn_browse.clicked.connect(self._on_browse)
+        dir_row.addWidget(self._edit_dir)
+        dir_row.addWidget(btn_browse)
+        out_form = _form()
+        out_form.addRow("Folder:", dir_row)
+        self._edit_prefix = QLineEdit(default_prefix)
+        out_form.addRow("File prefix:", self._edit_prefix)
+        ol.addLayout(out_form)
+        layout.addWidget(grp_out)
+
+        # ---- Channels ------------------------------------------------------
+        grp_ch, cl = _group("Channels  (fixed range, applied to every angle)")
+        grid = QGridLayout()
+        grid.setHorizontalSpacing(8)
+        grid.setVerticalSpacing(6)
+        grid.addWidget(_wrap_label("min:", _CSS_HINT), 0, 1)
+        grid.addWidget(_wrap_label("max:", _CSS_HINT), 0, 2)
+
+        self._rows: list[tuple[QCheckBox, QDoubleSpinBox, QDoubleSpinBox]] = []
+        for i, (ch_idx, is_velocity, label, unit, _tag) in enumerate(self._ROWS, 1):
+            chk = QCheckBox(label + (f"  [{unit}]" if unit else ""))
+            chk.setChecked(not is_velocity and ch_idx in self._DEFAULT_CHECKED)
+            vmin, vmax = default_ranges.get((ch_idx, is_velocity), (0.0, 1.0))
+            spin_min, spin_max = QDoubleSpinBox(), QDoubleSpinBox()
+            for spin, val in ((spin_min, vmin), (spin_max, vmax)):
+                spin.setRange(-1e9, 1e9)
+                spin.setDecimals(4)
+                spin.setMinimumWidth(_SPIN_MIN_W)
+                spin.setValue(val)
+            grid.addWidget(chk, i, 0)
+            grid.addWidget(spin_min, i, 1)
+            grid.addWidget(spin_max, i, 2)
+            self._rows.append((chk, spin_min, spin_max))
+        cl.addLayout(grid)
+        layout.addWidget(grp_ch)
+
+        # ---- Buttons --------------------------------------------------
+        buttons = QDialogButtonBox()
+        buttons.addButton("Export", QDialogButtonBox.ButtonRole.AcceptRole
+                          ).clicked.connect(self.accept)
+        buttons.addButton("Cancel", QDialogButtonBox.ButtonRole.RejectRole
+                          ).clicked.connect(self.reject)
+        layout.addWidget(buttons)
+
+    def _on_browse(self):
+        d = QFileDialog.getExistingDirectory(
+            self, "Select Output Folder", self._edit_dir.text())
+        if d:
+            self._edit_dir.setText(d)
+
+    def accept(self):
+        """Validate before closing — Cancel bypasses this entirely."""
+        if not self.get_prefix():
+            QMessageBox.warning(self, "Batch Export", "Enter a file prefix.")
+            return
+        if not self.get_output_dir():
+            QMessageBox.warning(self, "Batch Export", "Choose an output folder.")
+            return
+        selected = self.get_selected_channels()
+        if not selected:
+            QMessageBox.warning(
+                self, "Batch Export", "Select at least one channel to export.")
+            return
+        for ch in selected:
+            if not ch.vmin < ch.vmax:
+                QMessageBox.warning(
+                    self, "Batch Export", f"{ch.label}: min must be less than max.")
+                return
+        super().accept()
+
+    def get_output_dir(self) -> str:
+        return self._edit_dir.text().strip()
+
+    def get_prefix(self) -> str:
+        return self._edit_prefix.text().strip()
+
+    def get_selected_channels(self) -> list[ExportChannel]:
+        result = []
+        for (chk, spin_min, spin_max), (ch_idx, is_velocity, label, unit, tag) in zip(
+                self._rows, self._ROWS):
+            if chk.isChecked():
+                result.append(ExportChannel(
+                    ch_idx=ch_idx, is_velocity=is_velocity,
+                    vmin=spin_min.value(), vmax=spin_max.value(),
+                    label=label, unit=unit, tag=tag))
+        return result
+
+
 # ---------------------------------------------------------------------------
 # Export Fused ROI dialog
 # ---------------------------------------------------------------------------

sras_viewer/main_window.py

@@ -9,8 +9,8 @@ from PyQt6.QtCore import QObject, QSettings, QSignalBlocker, Qt, QThread
 from PyQt6.QtGui import QAction
 from PyQt6.QtWidgets import (
     QApplication, QCheckBox, QComboBox, QDialog, QFileDialog, QFrame,
-    QHBoxLayout, QLabel, QMainWindow, QProgressDialog, QPushButton,
+    QHBoxLayout, QLabel, QMainWindow, QMessageBox, QProgressDialog,
-    QSizePolicy, QSpinBox, QSplitter, QVBoxLayout, QWidget,
+    QPushButton, QSizePolicy, QSpinBox, QSplitter, QVBoxLayout, QWidget,
 )
 
 import sras_compute as compute
@@ -19,11 +19,12 @@ from sras_compute import (
     load_manual_alignment, save_manual_alignment, sidecar_path,
 )
 from sras_format import (
-    CH3_IDX, CH4_IDX, CH_NAMES, SrasFile, mv_to_adc,
+    CH1_IDX, CH3_IDX, CH4_IDX, CH_NAMES, SrasFile, mv_to_adc,
     _FALLBACK_YMULT_MV, _FALLBACK_YOFF_ADC,
 )
 from sras_workers import (
-    BatchCacheWorker, ComputeWorker, DcPrecomputeWorker, LoadWorker,
+    BatchCacheWorker, BatchExportWorker, ComputeWorker, DcPrecomputeWorker,
+    LoadWorker,
 )
 
 from .canvases import ImageCanvas, WaveformCanvas
@@ -35,7 +36,8 @@ from .common import (
 )
 from .align_wizard import AlignmentWizard
 from .dialogs import (
-    FftOptionsDialog, FusedRoiExportDialog, RowAverageFftOptionsDialog,
+    BatchExportDialog, FftOptionsDialog, FusedRoiExportDialog,
+    RowAverageFftOptionsDialog,
 )
 
 # ---------------------------------------------------------------------------
@@ -85,6 +87,10 @@ class SrasViewerWindow(QMainWindow):
         # Convert menu: batch DC/FFT compute-and-store (v6 -> v7)
         self._batch_errors: list[str] = []
 
+        # Export menu: batch image export
+        self._export_errors: list[str] = []
+        self._export_ok_count: int = 0
+
         # Display-only settings (colormap, grating) never trigger a
         # recompute — they're applied to cached data on redraw. DC images
         # (CH3/CH4) are cheap and precomputed for every angle in the
@@ -480,6 +486,15 @@ class SrasViewerWindow(QMainWindow):
         self._batch_fft_rowavg_act.triggered.connect(self._on_batch_compute_row_avg)
         convert_menu.addAction(self._batch_fft_rowavg_act)
 
+        export_menu = menubar.addMenu("&Export")
+        self._batch_export_act = QAction("&Batch Export Images…", self)
+        self._batch_export_act.setStatusTip(
+            "Export DC/RF/Velocity map PNGs for every angle of the open "
+            "file, with a fixed colorbar range per channel.")
+        self._batch_export_act.setEnabled(False)
+        self._batch_export_act.triggered.connect(self._on_batch_export)
+        export_menu.addAction(self._batch_export_act)
+
     # ------------------------------------------------------------------
     # Drag-and-drop
     # ------------------------------------------------------------------
@@ -702,6 +717,8 @@ class SrasViewerWindow(QMainWindow):
         self._wizard_act.setEnabled(
             has_file and s.n_angles > 1 and self._align_wizard is None)
         self.chk_aligned_view.setEnabled(enabled and self._alignment_result is not None)
+
+        self._batch_export_act.setEnabled(has_file and not self._job_running(Jobs.EXPORT))
         self._update_roi_ui()
 
     def _on_channel_changed(self):
@@ -1538,6 +1555,106 @@ class SrasViewerWindow(QMainWindow):
         self._batch_fft_act.setEnabled(True)
         self._batch_fft_rowavg_act.setEnabled(True)
 
+    # ------------------------------------------------------------------
+    # Export menu: batch image export
+    # ------------------------------------------------------------------
+
+    def _export_default_ranges(self) -> dict[tuple[int, bool], tuple[float, float]]:
+        """Best-effort default min/max per exportable channel, from whatever
+        is already cached — this must never trigger a fresh compute just to
+        seed the dialog (CH1/Velocity in particular can be expensive)."""
+        s = self._sras
+        ranges: dict[tuple[int, bool], tuple[float, float]] = {}
+
+        for ch_idx, precomputed in ((CH3_IDX, s.precomputed_dc3_mv),
+                                    (CH4_IDX, s.precomputed_dc4_mv)):
+            arrays = [self._dc_cache.get((a, ch_idx)) for a in range(s.n_angles)]
+            arrays = [a for a in arrays if a is not None]
+            if not arrays:
+                arrays = [a for a in precomputed if a is not None]
+            if arrays:
+                ranges[(ch_idx, False)] = (
+                    float(min(a.min() for a in arrays)),
+                    float(max(a.max() for a in arrays)))
+
+        freq_arrays = list(self._fft_cache.values())
+        if not freq_arrays:
+            freq_arrays = [a for a in s.precomputed_freq_mhz if a is not None]
+        if freq_arrays:
+            fmin = float(min(a.min() for a in freq_arrays))
+            fmax = float(max(a.max() for a in freq_arrays))
+            ranges[(CH1_IDX, False)] = (fmin, fmax)
+            grating = self.spin_grating_um.value()
+            ranges[(CH1_IDX, True)] = (fmin * grating, fmax * grating)
+
+        return ranges
+
+    def _on_batch_export(self):
+        if self._sras is None or self._job_running(Jobs.EXPORT):
+            return
+        s = self._sras
+
+        dlg = BatchExportDialog(
+            self, default_dir=str(s.path.parent), default_prefix=s.path.stem,
+            default_ranges=self._export_default_ranges())
+        if dlg.exec() != QDialog.DialogCode.Accepted:
+            return
+
+        output_dir = dlg.get_output_dir()
+        try:
+            Path(output_dir).mkdir(parents=True, exist_ok=True)
+        except OSError as exc:
+            QMessageBox.warning(
+                self, "Batch Export", f"Could not create output folder:\n{exc}")
+            return
+
+        channels = dlg.get_selected_channels()
+        self._export_errors = []
+        self._export_ok_count = 0
+        worker = BatchExportWorker(
+            s, channels, output_dir, dlg.get_prefix(),
+            cmap=self.combo_cmap.currentText(),
+            apply_bg_sub=self.chk_bg_sub.isChecked(),
+            dc_threshold_mv=self.spin_threshold_mv.value(),
+            n_fft=self._current_n_fft(), grating_um=self.spin_grating_um.value())
+        started = self._run_worker(
+            Jobs.EXPORT, worker,
+            connect=(
+                ("progress", lambda pct: self._set_progress(Jobs.EXPORT, pct)),
+                ("file_done", self._on_export_file_done),
+                ("finished", self._on_export_finished),
+            ),
+            on_done=self._after_export,
+        )
+        if not started:
+            return   # a second trigger snuck in while the dialog was open
+
+        self._batch_export_act.setEnabled(False)
+        self._show_progress(
+            Jobs.EXPORT, f"Exporting images to {output_dir}…", maximum=100)
+
+    def _on_export_file_done(self, path: str, err: str):
+        if err:
+            self._export_errors.append(f"{Path(path).name if path else '?'} — {err}")
+        else:
+            self._export_ok_count += 1
+            self._show_progress(Jobs.EXPORT, f"Wrote {Path(path).name}…")
+
+    def _on_export_finished(self):
+        self._close_progress(Jobs.EXPORT)
+        n_ok = self._export_ok_count
+        n_failed = len(self._export_errors)
+        if n_failed:
+            summary = (f"Batch export: {n_ok} image(s) written, {n_failed} "
+                       f"failed: {'; '.join(self._export_errors)}")
+        else:
+            summary = f"Batch export: {n_ok} image(s) written."
+        self.statusBar().showMessage(summary)
+        self._export_errors = []
+
+    def _after_export(self):
+        self._update_controls_enabled(self._sras is not None)
+
     # ------------------------------------------------------------------
     # Fusion: angle alignment
     # ------------------------------------------------------------------

tests/test_compute.py

@@ -327,21 +327,26 @@ def test_sras_average(tmp_path):
     assert np.array_equal(avg.background, SrasFile(str(src)).background), \
         "background preserved"
     src_data = meta["data"]
-    expect0 = src_data[0][:, :, 0:4, :].astype(np.float32).mean(axis=2).astype(np.int16)
+    # int16 (not float32) before .mean(): matches average_rows' own
+    # float64-accumulator behavior for integer input, so this doesn't
+    # drift from what average_rows actually guarantees.
+    expect0 = src_data[0][:, :, 0:4, :].astype(np.int16).mean(axis=2).astype(np.int16)
     assert np.array_equal(np.asarray(avg.data[0])[:, :, 0, :], expect0), \
         "first averaged group equals the mean of its 4 source frames"
 
     # Remainder handling: 12 frames / 5 -> 2 full groups + 1 partial.
     dst2 = tmp_path / "legacy_v4_avg5.sras"
-    subprocess.run([sys.executable, str(REPO / "sras_average.py"),
+    proc2 = subprocess.run([sys.executable, str(REPO / "sras_average.py"),
-                    str(src), str(dst2), "--n", "5"],
+                            str(src), str(dst2), "--n", "5"],
-                   capture_output=True, text=True, cwd=REPO)
+                           capture_output=True, text=True, cwd=REPO)
+    assert proc2.returncode == 0, (proc2.stderr or proc2.stdout).strip()[-200:]
     assert list(SrasFile(str(dst2)).n_frames) == [3, 3], \
         "partial trailing group kept by default"
     dst3 = tmp_path / "legacy_v4_avg5d.sras"
-    subprocess.run([sys.executable, str(REPO / "sras_average.py"),
+    proc3 = subprocess.run([sys.executable, str(REPO / "sras_average.py"),
-                    str(src), str(dst3), "--n", "5", "--discard-remainder"],
+                            str(src), str(dst3), "--n", "5", "--discard-remainder"],
-                   capture_output=True, text=True, cwd=REPO)
+                           capture_output=True, text=True, cwd=REPO)
+    assert proc3.returncode == 0, (proc3.stderr or proc3.stdout).strip()[-200:]
     assert list(SrasFile(str(dst3)).n_frames) == [2, 2], \
         "--discard-remainder drops the partial group"