Try img2pdf to generate the pdf

Issue : Xournal can't edit ??

annotating_with_checks.py

@@ -4,6 +4,7 @@ import json
 import shutil
 import concurrent.futures
 import threading
+import img2pdf
 
 # Fix for Matplotlib in threads: Set backend to non-interactive 'Agg'
 import matplotlib
@@ -224,8 +225,17 @@ def process_student(args):
     with open(os.path.join(output_dir, "checkboxes.json"), "w") as f:
         json.dump(final_json_map, f, indent=2)
 
-    concat_img.save(os.path.join(output_dir, "Reference.png"))
-    concat_img.save(os.path.join(output_dir, "Concat.pdf"), "PDF", resolution=DPI)
+
+    # Pour éviter du drift
+    temp_img_path = os.path.join(output_dir, "Reference.jpg")
+    concat_img.save(temp_img_path, quality=90) # Save as standard image first
+    with open(os.path.join(output_dir, "Concat.pdf"), "wb") as f:
+        f.write(img2pdf.convert(temp_img_path))
+
+    # Ancien code, avec du drift
+    # concat_img.save(os.path.join(output_dir, "Concat.pdf"), "PDF", resolution=DPI)
+    # concat_img.save(os.path.join(output_dir, "Reference.png"))
+
 
 
 if __name__ == "__main__":

reading_annotations.py

@@ -17,7 +17,8 @@ def detect_checks_and_notes(output_dir):
         notes_img: RGBA image of manual notes (checks masked out)
     """
     pdf_path = os.path.join(output_dir, "Concat_annotated.pdf")
-    ref_path = os.path.join(output_dir, "Reference.png")
+    # ref_path = os.path.join(output_dir, "Reference.png")
+    ref_path = os.path.join(output_dir, "Reference.jpg")
     json_path = os.path.join(output_dir, "checkboxes.json")
 
     if not (os.path.exists(pdf_path) and os.path.exists(ref_path)):
@@ -39,9 +40,7 @@ def detect_checks_and_notes(output_dir):
     except Exception as e:
         print(f"Error reading PDF: {e}")
         return [], None
-    # print("Debug : user_pages", len(user_pages))
     # Concatenate PDF pages back to one image if user saved as multiple pages
-    # (Xournal++ might preserve the long format or split it)
     total_h = sum(p.height for p in user_pages)
     user_img = Image.new("RGB", (user_pages[0].width, total_h))
     y = 0
@@ -72,7 +71,7 @@ def detect_checks_and_notes(output_dir):
     DENSITY_THRESHOLD = 0.05 # 5% of pixels darkened
 
     # Mask to hide checkmarks from the "Notes" extraction
-    mask_img = Image.new("L", ref_img.size, 255) # White = keep, Black = hide
+    mask_img = Image.new("L", ref_img.size, 255) # White (255) = keep, Black (0) = hide
     mask_draw = ImageDraw.Draw(mask_img)
 
     for box in boxes:
@@ -131,6 +130,12 @@ def detect_checks_and_notes(output_dir):
 
     notes.putalpha(Image.fromarray(final_alpha))
 
+    # Debuging : Issues
+    # - The artifacts increase as we go lower in the image
+    # - Tous les rectangles sont présents
+    # - 
+    notes.show()
+
     return actions, notes
 
 from PIL import ImageDraw