Unsplit a diptych from the filmstrip

docs/USER_GUIDE.md

@@ -92,7 +92,7 @@ Toolbar buttons, left to right:
 *   **RGB Scan**: treats the folder as red/green/blue exposure triplets and assembles each frame from three shots, for narrowband trichrome scanning. Right-click a frame → **Edit RGB Triplet…** to assign the three files by hand. An assembled frame carries the three-dot badge described under [Triage](#triage-culling-the-roll).
 *   **Half Frame**: splits each scan into two frames, for half-frame cameras. Each half is edited and metered separately and badged with which half it is. Enabling it opens a rectangle editor on the current scan: drag the green box to crop (everything outside is discarded), drag the orange line to set the split, and use **Cut thickness** to discard a band centred on the split, which is the physical black separator between the two exposures. The setting is saved and applied to every half-frame split from then on, whatever the scans were acquired with (SANE scanner, camera copy-stand, or folder import). **Adjust Half Frame**, beside Half Frame, re-opens the editor. Auto-detection of the gutter still seeds the initial split position.
 
-    Turning Half Frame off does not lose the work: each half you edited keeps its own edit. A half you only looked at is not work, so turning Half Frame on and back off again leaves the scan as it was. A scan you did split comes back as one frame carrying both halves, a **diptych**: half 1 rendered with its own edit, half 2 with its own, joined side by side at the original spacing, with the cut band as a black gap. A scan whose halves hold edits from another folder or an earlier session is not a diptych; it stays one plain frame until you split it again. A diptych carries the both-sides-filled split badge and exports as one file named `<name>-DIPTYCH`. Its controls panel is disabled, because the edits belong to the halves: turn Half Frame back on to change either one. A scan where only one half was worked on uses that half's edit for both sides. The filmstrip thumbnail and contact-sheet tile still show the plain whole scan, so a diptych's thumbnail does not match what it exports. An export size set as a long edge applies to each half, so a diptych comes out about twice that wide.
+    Turning Half Frame off does not lose the work: each half you edited keeps its own edit. A half you only looked at is not work, so turning Half Frame on and back off again leaves the scan as it was. A scan you did split comes back as one frame carrying both halves, a **diptych**: half 1 rendered with its own edit, half 2 with its own, joined side by side at the original spacing, with the cut band as a black gap. A scan whose halves hold edits from another folder or an earlier session is not a diptych; it stays one plain frame until you split it again. A diptych carries the both-sides-filled split badge and exports as one file named `<name>-DIPTYCH`. Its controls panel is disabled, because the edits belong to the halves: turn Half Frame back on to change either one. A scan where only one half was worked on uses that half's edit for both sides. The filmstrip thumbnail and contact-sheet tile still show the plain whole scan, so a diptych's thumbnail does not match what it exports. An export size set as a long edge applies to each half, so a diptych comes out about twice that wide. To get a plain frame back, right-click the diptych and select **Unsplit diptych**: it renders and exports whole again, and both halves' edits are deleted, so a later split starts from defaults.
 
     Half Frame does not apply to a frame assembled from more than one file: an RGB Scan triplet, a stitch, or an HDR merge. Those are never split, and they never come back as a diptych, even when the file they are built around was worked on as two halves earlier.
 *   **Apply (clone)**: copy the current frame's settings to selected frames or the whole roll. You choose which aspects in a dialog; crop and rotation are always per-image.

negpy/desktop/controller.py

@@ -70,6 +70,7 @@
 from negpy.services.assets.half_frame import (
     base_hash,
     diptych_configs,
+    forget_split_scan,
     half_hash,
     half_of,
     is_composite,
@@ -3467,6 +3468,31 @@ def request_unmerge_hdr(self) -> None:
         self._pending_scanned_file = paths[0]
         self.request_asset_discovery(paths)
 
+    def request_undiptych(self) -> None:
+        """Turn the active diptych back into one plain scan, deleting both halves' edits.
+
+        The scan leaves the split-scan set, so it stays a plain frame until it is split
+        again. Exported ``.negpy`` half sidecars are left alone.
+        """
+        idx = self.state.selected_file_idx
+        if not (0 <= idx < len(self.state.uploaded_files)):
+            return
+        asset = self.state.uploaded_files[idx]
+        file_hash = asset.get("hash") or ""
+        if not asset.get("diptych") or not file_hash:
+            return
+        forget_split_scan(self.session.repo, file_hash)
+        for n in (1, 2):
+            half = half_hash(file_hash, n)
+            self.session.repo.delete_file_settings(half)
+            self._measured_half_rows.discard(half)
+        asset["diptych"] = False
+        self._active_diptych_memo = ("", None)
+        self.session.asset_model.refresh()
+        if file_hash == self.state.current_file_hash and asset.get("path"):
+            self.load_file(asset["path"])
+        self.set_status("Diptych unsplit — the halves' edits are deleted", 4000)
+
     def _select_file_by_path(self, path: str) -> bool:
         """Find a file by path in uploaded_files and select it."""
         for i, f_info in enumerate(self.session.state.uploaded_files):

negpy/desktop/view/keyboard_shortcuts.py

@@ -113,6 +113,8 @@ def _build_actions(self) -> dict[str, Callable[[], None]]:
             "toggle_keep": lambda: controller.session.toggle_mark("keeper"),
             "hdr_merge": controller.request_hdr_merge_selected,
             "hdr_unmerge": controller.request_unmerge_hdr,
+            # The view method, not the controller's: it carries the confirm the deletion needs.
+            "half_frame_undiptych": self.window.session_panel.file_browser.prompt_undiptych,
             "toggle_reject": lambda: controller.session.toggle_mark("excluded"),
             "toggle_compare": controller.toggle_compare,
             "rotate_ccw": lambda: toolbar.rotate(1),

negpy/desktop/view/shortcut_registry.py

@@ -25,6 +25,7 @@ class ShortcutEntry:
     # fire activatedAmbiguously and kills both actions.
     "hdr_merge": ShortcutEntry("", "Merge selected exposures into one HDR frame", "Triage"),
     "hdr_unmerge": ShortcutEntry("", "Unmerge an HDR frame back into its exposures", "Triage"),
+    "half_frame_undiptych": ShortcutEntry("", "Unsplit a diptych back into one plain frame", "Triage"),
     "toggle_compare": ShortcutEntry("\\", "Before/after split (auto baseline)", "Tools"),
     "rotate_cw": ShortcutEntry("]", "Rotate 90° CW", "Geometry"),
     "rotate_ccw": ShortcutEntry("[", "Rotate 90° CCW", "Geometry"),

negpy/desktop/view/sidebar/files.py

@@ -1139,11 +1139,26 @@ def _build_context_menu(self) -> QMenu:
             if active.get("hdr_paths"):
                 self._add_hdr_anchor_menu(menu, active)
                 menu.addAction("Unmerge exposures").triggered.connect(lambda: self.controller.request_unmerge_hdr())
+            if active.get("diptych"):
+                menu.addAction("Unsplit diptych").triggered.connect(self.prompt_undiptych)
         menu.addSeparator()
         unload_label = "Unload Selected" if multi else "Unload"
         menu.addAction(unload_label).triggered.connect(self._on_remove_from_menu)
         return menu
 
+    def prompt_undiptych(self) -> None:
+        """Confirm before the halves' edits go, then hand the frame back as one plain scan."""
+        box = QMessageBox(self)
+        box.setIcon(QMessageBox.Icon.Warning)
+        box.setWindowTitle("Unsplit diptych")
+        box.setText("Turn this diptych back into one plain frame?")
+        box.setInformativeText("Both halves' edits are deleted. Splitting the scan again starts from defaults.")
+        unsplit = box.addButton("Unsplit", QMessageBox.ButtonRole.AcceptRole)
+        box.addButton("Cancel", QMessageBox.ButtonRole.RejectRole)
+        box.exec()
+        if box.clickedButton() is unsplit:
+            self.controller.request_undiptych()
+
     def _add_hdr_merge_action(self, menu, state) -> None:
         """Merging is for transparencies, so the action follows the film process.
 

negpy/domain/interfaces.py

@@ -59,6 +59,8 @@ def load_file_settings_by_path(self, file_path: str) -> Optional[tuple[str, "Wor
 
     def rehome_file_settings(self, old_hash: str, new_hash: str, file_path: str) -> None: ...
 
+    def delete_file_settings(self, file_hash: str) -> None: ...
+
     def save_global_setting(self, key: str, value: Any) -> None: ...
     def save_global_settings(self, settings: dict[str, Any]) -> None: ...
     def get_global_setting(self, key: str, default: Any = None) -> Any: ...

negpy/infrastructure/storage/repository.py

@@ -196,6 +196,15 @@ def load_file_settings(self, file_hash: str) -> Optional[WorkspaceConfig]:
                 return WorkspaceConfig.from_flat_dict(data)
         return None
 
+    def delete_file_settings(self, file_hash: str) -> None:
+        """Delete this hash's saved edit, its undo history and its work prints.
+
+        The triage mark stays: a keep/reject is a judgement on the frame, not an edit.
+        """
+        with self._connect(self.edits_db_path) as conn:
+            for table in ("file_settings", "edit_history", "work_prints"):
+                conn.execute(f"DELETE FROM {table} WHERE file_hash = ?", (file_hash,))
+
     def load_file_settings_many(self, hashes: List[str]) -> dict[str, WorkspaceConfig]:
         """Saved edits for many hashes in one connection — the search facts for a whole
         roll cost one round trip, not one per frame. Hashes with no saved edit are absent

negpy/services/assets/half_frame.py

@@ -54,6 +54,13 @@ def remember_split_scans(repo: Any, hashes: Any) -> None:
         repo.save_global_setting(SPLIT_SCANS_KEY, sorted(new))
 
 
+def forget_split_scan(repo: Any, file_hash: Optional[str]) -> None:
+    """Drop a base hash from the split-scan set, so the scan is no longer a diptych."""
+    known = split_scans(repo)
+    if file_hash in known:
+        repo.save_global_setting(SPLIT_SCANS_KEY, sorted(known - {file_hash}))
+
+
 def half_hash(file_hash: str, half: int) -> str:
     return f"{file_hash}{_SEP}{half}"
 

tests/test_file_browser_widget.py

@@ -132,6 +132,21 @@ def test_context_menu_single_selection_items(browser, session):
     assert "Apply settings…" in labels
 
 
+def test_context_menu_offers_unsplit_only_for_a_diptych(browser, session):
+    session.state.selected_indices = [0]
+    session.state.selected_file_idx = 0
+    assert "Unsplit diptych" not in _action_labels(browser._build_context_menu())
+
+    session.state.uploaded_files[0]["diptych"] = True
+    assert "Unsplit diptych" in _action_labels(browser._build_context_menu())
+
+
+def test_unsplit_diptych_needs_the_confirm(browser):
+    with patch("negpy.desktop.view.sidebar.files.QMessageBox.exec"):
+        browser.prompt_undiptych()  # no button clicked: rejected
+    browser.controller.request_undiptych.assert_not_called()
+
+
 def test_context_menu_multi_selection_uses_export_selected(browser, session):
     session.state.selected_indices = [0, 1]
     session.state.selected_file_idx = 0

tests/test_half_frame.py

@@ -12,6 +12,7 @@
     detect_split_x,
     SPLIT_SCANS_KEY,
     diptych_configs,
+    forget_split_scan,
     gap_px,
     half_hash,
     half_name,
@@ -306,6 +307,14 @@ def test_remember_split_scans_unions_and_skips_a_known_write(self):
         remember_split_scans(repo, {"h"})
         repo.save_global_setting.assert_not_called()
 
+    def test_forget_split_scan_drops_one_hash_and_skips_an_unknown_write(self):
+        repo = self._repo({"h#1": WorkspaceConfig()}, split=("g", "h"))
+        forget_split_scan(repo, "h")
+        repo.save_global_setting.assert_called_once_with(SPLIT_SCANS_KEY, ["g"])
+        repo.save_global_setting.reset_mock()
+        forget_split_scan(repo, "z")
+        repo.save_global_setting.assert_not_called()
+
     def test_export_filename_is_not_a_half(self):
         name = render_export_filename("/x/IMG420.tif", ExportConfig(), composite="DIPTYCH")
         assert name.endswith("IMG420-DIPTYCH") and "IMG420_1" not in name
@@ -461,6 +470,42 @@ def test_a_flagged_negative_skips_the_lookup(self):
         assert pair is None and info["hash"] == "ha"
         ctrl.session.repo.load_file_settings_many.assert_not_called()
 
+    def test_undiptych_forgets_the_split_and_deletes_both_halves(self):
+        from negpy.desktop.controller import AppController
+
+        ctrl = self._controller({"ha#1": WorkspaceConfig(), "ha#2": WorkspaceConfig()})
+        asset = {"path": "/p/a.tif", "hash": "ha", "diptych": True}
+        ctrl.state = MagicMock()
+        ctrl.state.selected_file_idx = 0
+        ctrl.state.uploaded_files = [asset]
+        ctrl.state.current_file_hash = "ha"
+        ctrl._measured_half_rows = {"ha#1"}
+        ctrl.set_status = MagicMock()
+        ctrl.load_file = MagicMock()
+
+        AppController.request_undiptych(ctrl)
+
+        ctrl.session.repo.save_global_setting.assert_called_once_with(SPLIT_SCANS_KEY, [])
+        assert [c.args[0] for c in ctrl.session.repo.delete_file_settings.call_args_list] == ["ha#1", "ha#2"]
+        assert asset["diptych"] is False
+        assert ctrl._measured_half_rows == set()  # or a re-meter files a row again
+        assert ctrl._active_diptych_memo == ("", None)
+        ctrl.load_file.assert_called_once_with("/p/a.tif")
+
+    def test_undiptych_leaves_a_plain_frame_alone(self):
+        from negpy.desktop.controller import AppController
+
+        ctrl = self._controller({})
+        ctrl.state = MagicMock()
+        ctrl.state.selected_file_idx = 0
+        ctrl.state.uploaded_files = [{"path": "/p/a.tif", "hash": "ha"}]
+        ctrl.set_status = MagicMock()
+
+        AppController.request_undiptych(ctrl)
+
+        ctrl.session.repo.delete_file_settings.assert_not_called()
+        ctrl.session.repo.save_global_setting.assert_not_called()
+
     def test_composite_kind_and_summary(self):
         from negpy.desktop.session import composite_kind, composite_summary
 

tests/test_storage_repo.py

@@ -78,6 +78,24 @@ def test_load_settings_by_path_skips_rows_without_a_path(tmp_path):
     assert by_path["/a/1.nef"].metadata.film == "Portra"
 
 
+def test_delete_file_settings_takes_the_edit_history_and_work_prints(tmp_path):
+    repo = _repo(tmp_path)
+    for h in ("h1", "h2"):
+        repo.save_file_settings(h, _config("Portra"), file_path="/a/1.nef")
+        repo.save_history_step(h, 0, _config("Portra"))
+        repo.save_work_print(h, "print", _config("Portra"))
+    repo.save_file_mark("h1", "keeper", file_path="/a/1.nef")
+
+    repo.delete_file_settings("h1")
+
+    assert repo.load_file_settings("h1") is None
+    assert repo.load_history_step("h1", 0) is None
+    assert repo.list_work_prints("h1") == []
+    assert repo.load_file_marks() == {"h1": "keeper"}  # a triage mark is not an edit
+    assert repo.load_file_settings("h2") is not None
+    assert repo.list_work_prints("h2") == ["print"]
+
+
 def test_file_marks_are_resolvable_by_path(tmp_path):
     repo = _repo(tmp_path)
     repo.save_file_mark("h1", "keeper", file_path="/a/1.nef")

tests/test_updater.py

@@ -230,7 +230,9 @@ def test_the_windows_script_switches_cmd_to_utf8_before_the_paths():
     """cmd parses a batch file in the OEM codepage, not the UTF-8 it is written in. The
     staging path carries the profile name, so a non-ASCII user name garbles every path
     unless the script switches the codepage first."""
-    script = nsis_script(Path("C:\\Users\\José\\Temp\\Setup.exe"), Path(r"C:\Program Files\NegPy"), Path(r"C:\Program Files\NegPy\NegPy.exe"), 3)
+    script = nsis_script(
+        Path("C:\\Users\\José\\Temp\\Setup.exe"), Path(r"C:\Program Files\NegPy"), Path(r"C:\Program Files\NegPy\NegPy.exe"), 3
+    )
 
     assert "chcp 65001 >nul" in script
     assert script.index("chcp 65001") < script.index("José")