feat(python): add edit_states tool as example

Author: jbms

python/neuroglancer/tool/edit_states.py

@@ -0,0 +1,139 @@
+import argparse
+import json
+import pathlib
+import webbrowser
+
+import neuroglancer
+import neuroglancer.cli
+
+
+class Tool:
+    def __init__(
+        self,
+        viewer: neuroglancer.Viewer,
+        paths: list[pathlib.Path],
+        num_to_prefetch: int,
+    ) -> None:
+        self.viewer = viewer
+        self.paths = paths
+        self.num_to_prefetch = num_to_prefetch
+
+        key_bindings = [
+            ["bracketleft", "prev-index"],
+            ["bracketright", "next-index"],
+            ["home", "first-index"],
+            ["end", "last-index"],
+            ["control+keys", "save"],
+        ]
+        self.viewer.actions.add("prev-index", self._prev_index)
+        self.viewer.actions.add("next-index", self._next_index)
+        self.viewer.actions.add("first-index", self._first_index)
+        self.viewer.actions.add("last-index", self._last_index)
+        self.viewer.actions.add("save", self.save)
+
+        with self.viewer.config_state.txn() as s:
+            for key, command in key_bindings:
+                s.input_event_bindings.viewer[key] = command
+                s.input_event_bindings.data_view[key] = command
+            s.status_messages["help"] = "KEYS: " + " | ".join(
+                f"{key}={command}" for key, command in key_bindings
+            )
+
+        self.index = -1
+        self.set_index(0)
+
+    def set_index(self, index: int) -> None:
+        if index == self.index:
+            return
+        if index < 0:
+            index += len(self.paths)
+        elif index >= len(self.paths):
+            index -= len(self.paths)
+        if index < 0 or index >= len(self.paths):
+            return
+        self.save()
+        self.index = index
+        self.load()
+
+    def _get_state(self, index: int) -> neuroglancer.ViewerState:
+        content = self.paths[index].read_text(encoding="utf-8")
+        try:
+            state = neuroglancer.ViewerState(json.loads(content))
+        except json.JSONDecodeError:
+            state = neuroglancer.parse_url(content.strip())
+        return state
+
+    def save(self) -> None:
+        if self.index == -1:
+            return
+        state = self.viewer.state
+        path = self.paths[self.index]
+        existing_content = path.read_text(encoding="utf-8")
+        try:
+            json.loads(existing_content)
+            path.write_text(neuroglancer.to_json_dump(state))
+        except json.JSONDecodeError:
+            path.write_text(neuroglancer.to_url(state))
+
+    def load(self) -> None:
+        self.viewer.set_state(self._get_state(self.index))
+
+        prefetch_states = []
+        for i in range(self.num_to_prefetch):
+            prefetch_index = self.index + i + 1
+            if prefetch_index >= len(self.paths):
+                break
+            prefetch_states.append(self._get_state(prefetch_index))
+
+        with self.viewer.config_state.txn() as s:
+            s.prefetch = [
+                neuroglancer.PrefetchState(state=prefetch_state, priority=-i)
+                for i, prefetch_state in enumerate(prefetch_states)
+            ]
+
+        with self.viewer.config_state.txn() as s:
+            s.status_messages["status"] = "[State %d/%d] %s" % (
+                self.index,
+                len(self.paths),
+                self.paths[self.index],
+            )
+
+    def _first_index(self, s):
+        self.set_index(0)
+
+    def _last_index(self, s):
+        self.set_index(-1)
+
+    def _next_index(self, s):
+        self.set_index(self.index + 1)
+
+    def _prev_index(self, s):
+        self.set_index(self.index - 1)
+
+
+if __name__ == "__main__":
+    ap = argparse.ArgumentParser()
+    neuroglancer.cli.add_server_arguments(ap)
+    ap.add_argument(
+        "path",
+        nargs="*",
+        type=pathlib.Path,
+        help="Path to file containing URL or JSON state.",
+    )
+    ap.add_argument(
+        "--prefetch", type=int, default=10, help="Number of states to prefetch"
+    )
+    ap.add_argument("--browser", action="store_true", help="Open in browser.")
+
+    args = ap.parse_args()
+    neuroglancer.cli.handle_server_arguments(args)
+    viewer = neuroglancer.Viewer()
+
+    tool = Tool(
+        viewer=viewer,
+        paths=args.path,
+        num_to_prefetch=args.prefetch,
+    )
+    print(tool.viewer)
+    if args.browser:
+        webbrowser.open(str(tool.viewer))