Update ui/callbacks.py

ui/callbacks.py

@@ -8,10 +8,11 @@
 • PREVIEW FUNCTIONS NOW IMPLEMENTED:
     - cb_video_changed        → returns first frame
     - cb_custom_bg_preview    → returns uploaded image
+• UPDATED: Background preview persists during processing
 """
 
 from __future__ import annotations
-import os, cv2                             # ← cv2 was already needed by fallback gen
+import os, cv2
 from typing import Any, Dict, Tuple
 import numpy as np
 from PIL import Image
@@ -32,6 +33,9 @@
 except Exception:
     pass
 
+# Global to store current background for persistence
+current_background_image = None
+
 
 # ------------------------------------------------------------------
 # LIGHTWEIGHT BG GENERATOR (inline fallback)
@@ -146,14 +150,17 @@ def cb_process_video(
     custom_file: dict | None,
     use_two: bool,
     chroma: str,
-    key_color_mode: str,     # <-- NEW ARG from dropdown
+    key_color_mode: str,
     prev_mask: bool,
     prev_green: bool,
 ):
     """
     Runs the two-stage (or single-stage) pipeline and returns:
-        (processed_video_path | None, status_message:str)
+        (processed_video_path | None, status_message:str, background_preview)
+    Now returns THREE values to maintain background preview during processing.
     """
+    global current_background_image
+    
     # Reset any prior cancel flag when user clicks Run
     if PROCESS_CANCELLED.is_set():
         PROCESS_CANCELLED.clear()
@@ -162,19 +169,36 @@ def cb_process_video(
     custom_path = None
     if isinstance(custom_file, dict) and custom_file.get("name"):
         custom_path = custom_file["name"]
+        # Update the background preview for custom uploads
+        try:
+            img = Image.open(custom_path).convert("RGB")
+            current_background_image = np.array(img)
+        except Exception:
+            pass
+    elif not custom_file and style:
+        # Generate preview for preset background
+        try:
+            from utils.cv_processing import create_professional_background
+            # Create a preview-sized version of the preset
+            current_background_image = create_professional_background(style, 640, 360)
+        except Exception:
+            pass
 
     # Fire the core function
-    return process_video_fixed(
+    video_path, status = process_video_fixed(
         video_path=vid,
         background_choice=style,
         custom_background_path=custom_path,
-        progress_callback=None,          # UI-level progress handled inside
+        progress_callback=None,
         use_two_stage=use_two,
         chroma_preset=chroma,
-        key_color_mode=key_color_mode,   # <-- pass straight through
+        key_color_mode=key_color_mode,
         preview_mask=prev_mask,
         preview_greenscreen=prev_green,
     )
+    
+    # Return video, status, AND the background preview to keep it visible
+    return video_path, status, current_background_image
 
 
 # ------------------------------------------------------------------
@@ -194,19 +218,34 @@ def cb_status() -> Tuple[Dict[str, Any], Dict[str, Any]]:
         return {"error": str(e)}, {"error": str(e)}
 
 def cb_clear():
-    # Return blanks for (out_video, status, gen_preview, gen_path)
-    return None, "", None, ""
+    """Clear all outputs including the background preview"""
+    global current_background_image
+    current_background_image = None
+    # Return blanks for (out_video, status, gen_preview, gen_path, bg_preview)
+    return None, "", None, "", None
 
 
 # ------------------------------------------------------------------
 # AI BACKGROUND
 # ------------------------------------------------------------------
 def cb_generate_bg(prompt_text: str, w: int, h: int, b: float, v: float, c: float):
+    """Generate AI background and update global preview"""
+    global current_background_image
     img, path = _generate_ai_background(prompt_text, int(w), int(h), b, v, c)
+    # Store as numpy array for consistency
+    if img:
+        current_background_image = np.array(img)
     return img, path
 
 def cb_use_gen_bg(path_text: str):
+    """Use generated background as custom and update preview"""
+    global current_background_image
     if path_text and os.path.exists(path_text):
+        try:
+            img = Image.open(path_text).convert("RGB")
+            current_background_image = np.array(img)
+        except Exception:
+            pass
         return {"name": path_text, "size": os.path.getsize(path_text)}
     return None
 
@@ -236,11 +275,28 @@ def cb_video_changed(vid_path: str):
 def cb_custom_bg_preview(file_obj: dict | None):
     """
     Display the uploaded background image (if any) as a preview.
+    Stores it globally so it persists during processing.
     """
+    global current_background_image
     try:
         if file_obj and file_obj.get("name"):
             img = Image.open(file_obj["name"]).convert("RGB")
-            return np.array(img)
+            current_background_image = np.array(img)
+            return current_background_image
     except Exception:
         pass
     return None
+
+def cb_preset_bg_preview(style: str):
+    """
+    Generate and display preview for preset backgrounds.
+    Called when background style dropdown changes.
+    """
+    global current_background_image
+    try:
+        from utils.cv_processing import create_professional_background
+        # Create a preview-sized version
+        current_background_image = create_professional_background(style, 640, 360)
+        return current_background_image
+    except Exception:
+        return None