feat: imaging tensor loaders + change hash

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

gates/imaging.py

@@ -0,0 +1,30 @@
+"""Tensor/imaging helpers (torch + PIL). No comfy imports."""
+import hashlib
+import numpy as np
+import torch
+from PIL import Image, ImageOps
+
+
+def load_image_tensor(path):
+    img = Image.open(path)
+    img = ImageOps.exif_transpose(img).convert("RGB")
+    arr = np.array(img, dtype=np.float32) / 255.0
+    return torch.from_numpy(arr).unsqueeze(0)          # [1,H,W,3]
+
+
+def load_mask_tensor(path, h, w):
+    if not path:
+        return torch.zeros((1, h, w), dtype=torch.float32)
+    m = Image.open(path).convert("L")
+    arr = np.array(m, dtype=np.float32) / 255.0
+    return torch.from_numpy(arr).unsqueeze(0)          # [1,H,W]
+
+
+def empty_outputs():
+    return (torch.zeros((1, 1, 1, 3), dtype=torch.float32),
+            torch.zeros((1, 1, 1), dtype=torch.float32))
+
+
+def change_hash(pool_id, index, mtimes):
+    key = f"{pool_id}|{index}|" + "|".join(f"{t:.3f}" for t in mtimes)
+    return hashlib.sha256(key.encode()).hexdigest()

tests/test_imaging.py

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+import numpy as np, torch
+from PIL import Image
+from gates import imaging
+
+
+def _png(tmp_path, name, color, size=(4, 6)):  # size = (w, h)
+    p = tmp_path / name
+    Image.new("RGB", size, color).save(p)
+    return str(p)
+
+
+def test_load_image_tensor_shape_and_range(tmp_path):
+    t = imaging.load_image_tensor(_png(tmp_path, "a.png", (255, 0, 0)))
+    assert t.shape == (1, 6, 4, 3)         # [B,H,W,C]
+    assert t.dtype == torch.float32
+    assert 0.0 <= float(t.min()) and float(t.max()) <= 1.0
+    assert float(t[0, 0, 0, 0]) > 0.99     # red channel
+
+
+def test_load_mask_none_is_zeros():
+    m = imaging.load_mask_tensor(None, h=6, w=4)
+    assert m.shape == (1, 6, 4)
+    assert float(m.max()) == 0.0
+
+
+def test_load_mask_from_file(tmp_path):
+    p = tmp_path / "m.png"
+    Image.new("L", (4, 6), 255).save(p)
+    m = imaging.load_mask_tensor(str(p), h=6, w=4)
+    assert m.shape == (1, 6, 4)
+    assert float(m.min()) > 0.99
+
+
+def test_empty_image_is_1x1_black():
+    img, mask = imaging.empty_outputs()
+    assert img.shape == (1, 1, 1, 3) and float(img.max()) == 0.0
+    assert mask.shape == (1, 1, 1)
+
+
+def test_change_hash_changes_with_mtime():
+    h1 = imaging.change_hash("p", 0, [1000.0])
+    h2 = imaging.change_hash("p", 0, [1001.0])
+    assert h1 != h2