feat(v2): add multiple extra features from the pdf slides

backend/processing/services.py

@@ -1,10 +1,12 @@
 import time
 
+import numpy as np
 from django.conf import settings
 from django.utils import timezone
 
-from .algorithms import ProcessingError, decode_image, histogram, process_image
-from .models import ImageSession, ProcessingJob
+from .algorithms import ProcessingError, average_images, decode_image, histogram, histogram_payload, normalize_to_uint8, process_image, verify_registration
+from .models import ImageSession, ImageState, ProcessingJob
+from .registry import apply_registered_operation
 from .storage import load_image_array, payload_for_image, save_image_array
 from .tasks import run_batch_job
 
@@ -25,19 +27,145 @@ def image_session_create(*, uploaded_file=None, image_base64=None):
         original_histogram=hist,
         expires_at=timezone.now() + timezone.timedelta(hours=settings.IMAGE_SESSION_TTL_HOURS),
     )
+    state = image_state_create(
+        session=session,
+        parent=None,
+        image=image,
+        operation="upload",
+        params={},
+        label="S0 Upload",
+        prefix="state-upload",
+    )
     payload = {
         "session_id": str(session.id),
+        "active_state_id": str(state.id),
         "width": session.width,
         "height": session.height,
         "channels": session.channels,
         "color_mode": session.color_mode,
         "original_histogram": hist,
+        "histogram": state.histogram,
         "expires_at": session.expires_at.isoformat(),
+        "states": [image_state_payload(state=state, include_image=True)],
     }
     payload.update(payload_for_image(image, relative_path))
     return payload
 
 
+def image_state_create(*, session, parent, image, operation, params, label=None, prefix="state"):
+    relative_path = save_image_array(image, prefix)
+    sequence = session.states.count()
+    state = ImageState.objects.create(
+        session=session,
+        parent=parent,
+        sequence=sequence,
+        label=label or f"S{sequence} {operation}",
+        operation=operation,
+        params=params or {},
+        image=relative_path,
+        width=image.shape[1],
+        height=image.shape[0],
+        channels=image.shape[2] if image.ndim == 3 else 1,
+        color_mode="RGB" if image.ndim == 3 else "L",
+        histogram=histogram_payload(image),
+    )
+    return state
+
+
+def image_state_payload(*, state, include_image=True):
+    payload = {
+        "state_id": str(state.id),
+        "session_id": str(state.session_id),
+        "parent_state_id": str(state.parent_id) if state.parent_id else None,
+        "sequence": state.sequence,
+        "label": state.label,
+        "operation": state.operation,
+        "params": state.params,
+        "width": state.width,
+        "height": state.height,
+        "channels": state.channels,
+        "color_mode": state.color_mode,
+        "histogram": state.histogram,
+        "created_at": state.created_at.isoformat(),
+    }
+    if include_image:
+        image = load_image_array(state.image)
+        payload.update(payload_for_image(image, state.image))
+    else:
+        payload["image_path"] = state.image
+        payload["image_url"] = f"{settings.MEDIA_URL}{state.image}"
+    return payload
+
+
+def image_states_payload(*, states):
+    return [image_state_payload(state=state, include_image=True) for state in states]
+
+
+def image_state_apply_operation(*, state, operation, params):
+    if state.session.expired:
+        raise ProcessingError("Image session has expired.")
+    source = load_image_array(state.image)
+    result = apply_registered_operation(source, operation, params or {})
+    new_state = image_state_create(
+        session=state.session,
+        parent=state,
+        image=result,
+        operation=operation,
+        params=params or {},
+        label=None,
+        prefix=f"state-{operation}",
+    )
+    return image_state_payload(state=new_state, include_image=True)
+
+
+def combine_states(*, states, operation, params=None):
+    params = params or {}
+    if len(states) < 2:
+        raise ProcessingError("At least two states are required.")
+    session = states[0].session
+    if any(state.session_id != session.id for state in states):
+        raise ProcessingError("All states must belong to the same session.")
+    images = [load_image_array(state.image) for state in states]
+    verify_registration(images)
+
+    if operation == "average":
+        result = average_images(images)
+    elif operation == "add":
+        result = np_clip_sum(images)
+    elif operation == "subtract":
+        result = normalize_to_uint8(images[0].astype("float32") - images[1].astype("float32"))
+    elif operation == "dot_product":
+        result = normalize_to_uint8(np.prod([image.astype("float32") / 255.0 for image in images], axis=0))
+    elif operation == "and":
+        result = images[0].copy()
+        for image in images[1:]:
+            result = result & image
+    elif operation == "or":
+        result = images[0].copy()
+        for image in images[1:]:
+            result = result | image
+    else:
+        raise ProcessingError(f"Unsupported combine operation '{operation}'.")
+
+    new_state = image_state_create(
+        session=session,
+        parent=states[0],
+        image=result,
+        operation=f"combine_{operation}",
+        params={**params, "state_ids": [str(state.id) for state in states]},
+        label=None,
+        prefix=f"state-combine-{operation}",
+    )
+    return image_state_payload(state=new_state, include_image=True)
+
+
+def np_clip_sum(images):
+    total = np.zeros_like(images[0], dtype="float32")
+    for image in images:
+        total += image.astype("float32")
+    return np.clip(total, 0, 255).astype("uint8")
+
+
 def image_session_process(*, session, operation, params):
     if session.expired:
         raise ProcessingError("Image session has expired.")