Initial commit — Copydev Imposing Tool

Outil d'imposition PDF desktop (PyQt6) remplacant Quite Imposing Plus.
9 fonctions : livret, n-up, step & repeat, imposition manuelle,
jointure pages, pages blanches, numerotation, masquage, fonds perdus.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/engine/bleeds.py

@@ -0,0 +1,36 @@
+"""Moteur Definition des fonds perdus (bleeds)."""
+
+from pypdf import PdfReader, PdfWriter
+from .pdf_utils import get_page_size, mm_to_pt
+
+
+def define_bleeds(input_path, output_path, bleed_top=0, bleed_bottom=0,
+                  bleed_left=0, bleed_right=0):
+    """Definir les zones de fond perdu en etendant le TrimBox/BleedBox.
+
+    Les valeurs sont en millimetres.
+    """
+    bt = mm_to_pt(bleed_top)
+    bb = mm_to_pt(bleed_bottom)
+    bl = mm_to_pt(bleed_left)
+    br = mm_to_pt(bleed_right)
+
+    reader = PdfReader(input_path)
+    writer = PdfWriter()
+
+    for page in reader.pages:
+        w, h = get_page_size(page)
+
+        # Le TrimBox definit la taille finale apres coupe
+        page.trimbox.lower_left = (bl, bb)
+        page.trimbox.upper_right = (w - br, h - bt)
+
+        # Le BleedBox inclut le fond perdu
+        page.bleedbox.lower_left = (0, 0)
+        page.bleedbox.upper_right = (w, h)
+
+        writer.add_page(page)
+
+    with open(output_path, "wb") as f:
+        writer.write(f)
+    return output_path