initial commit

labelstore.py

@@ -0,0 +1,55 @@
+"""Persistence for sprite frame label assignments.
+
+Assignments are stored in a JSON sidecar keyed by filename (not frame index),
+so resuming a session survives frames being added, removed, or reordered.
+"""
+
+import json
+from pathlib import Path
+
+SIDECAR_NAME = '.sprite_tags.json'
+SCHEMA_VERSION = 1
+
+
+def sidecar_path(frames_dir: Path) -> Path:
+    return frames_dir / SIDECAR_NAME
+
+
+def save_labels(path: Path, assignments_by_name: dict, labels: list) -> None:
+    data = {
+        'version': SCHEMA_VERSION,
+        'labels': list(labels),
+        'assignments': dict(assignments_by_name),
+    }
+    Path(path).write_text(json.dumps(data, indent=2))
+
+
+def load_labels(path: Path):
+    """Return (assignments_by_name, labels). Missing or invalid file → ({}, [])."""
+    path = Path(path)
+    if not path.exists():
+        return {}, []
+    try:
+        data = json.loads(path.read_text())
+    except (json.JSONDecodeError, OSError, ValueError):
+        return {}, []
+    assignments = data.get('assignments', {})
+    labels = data.get('labels', [])
+    if not isinstance(assignments, dict) or not isinstance(labels, list):
+        return {}, []
+    return assignments, labels
+
+
+def to_name_keyed(assignments_by_index: dict, frames: list) -> dict:
+    """{index: label} → {filename: label}."""
+    return {frames[i].name: label for i, label in assignments_by_index.items()}
+
+
+def to_index_keyed(assignments_by_name: dict, frames: list) -> dict:
+    """{filename: label} → {index: label}, dropping files not in `frames`."""
+    name_to_index = {p.name: i for i, p in enumerate(frames)}
+    return {
+        name_to_index[name]: label
+        for name, label in assignments_by_name.items()
+        if name in name_to_index
+    }