Fix blank label between copies: send all copies in single GDI print job (StartDoc/N pages/EndDoc) instead of N separate jobs - thermal printers eject blank label between rapid separate jobs

label_printer_gui.py

@@ -982,23 +982,13 @@ printer = PDF
             success = False
             all_success = True
             try:
-                # Print multiple copies if count > 1
+                # Send all copies in ONE print job to prevent blank labels
-                for i in range(count):
+                # being ejected between separate jobs on thermal printers.
-                    if count > 1:
+                success = print_label_standalone(
-                        Clock.schedule_once(lambda dt, idx=i: popup.content.children[0].text.replace(
+                    label_text, printer, preview=0,
-                            f'Processing {count} label(s)...',
+                    svg_template=template_path, copies=count
-                            f'Printing {idx+1} of {count}...'
+                )
-                        ), 0)
+                all_success = success
-                    
-                    success = print_label_standalone(label_text, printer, preview=0, svg_template=template_path)
-                    
-                    if not success:
-                        all_success = False
-                        break
-                    
-                    # Small delay between prints for multiple copies
-                    if i < count - 1:
-                        time.sleep(0.5)
                 
                 # Get the PDF filename that was created
                 # Files are saved to pdf_backup/ with timestamp

print_label.py

@@ -158,15 +158,18 @@ def create_label_pdf(text, svg_template=None):
     return generator.create_label_pdf(article, nr_art, serial, pdf_filename, image_path, selected_template)
 
 
-def _print_pdf_windows(file_path, printer_name):
+def _print_pdf_windows(file_path, printer_name, copies=1):
     """
     Print a PDF on Windows using pymupdf (fitz) to render and win32print/GDI to send.
+    All copies are sent as multiple pages within ONE print job so the printer
+    never sees a gap (which causes blank labels on thermal printers).
     No external application is launched.  Falls back to SumatraPDF if pymupdf
     is unavailable.
 
     Returns True on success, False on failure.
     """
-    _write_print_log(f"_print_pdf_windows called: printer={printer_name!r} file={file_path!r}")
+    copies = max(1, int(copies))
+    _write_print_log(f"_print_pdf_windows called: printer={printer_name!r} copies={copies} file={file_path!r}")
 
     # ── Method 1: pure-Python GDI (pymupdf + win32print) ─────────────────
     try:
@@ -207,16 +210,18 @@ def _print_pdf_windows(file_path, printer_name):
             f"rendered={pix.width}x{pix.height}px  dest={dest_w}x{dest_h}px"
         )
 
-        # Draw at exact physical size – NOT stretched to the driver's paper area
+        # Draw at exact physical size – NOT stretched to the driver's paper area.
+        # All copies go into ONE print job to prevent blank labels between jobs.
         hdc.StartDoc(os.path.basename(file_path))
-        hdc.StartPage()
         dib = ImageWin.Dib(img)
-        dib.draw(hdc.GetHandleOutput(), (0, 0, dest_w, dest_h))
+        for copy_idx in range(copies):
-        hdc.EndPage()
+            hdc.StartPage()
+            dib.draw(hdc.GetHandleOutput(), (0, 0, dest_w, dest_h))
+            hdc.EndPage()
         hdc.EndDoc()
         hdc.DeleteDC()
 
-        _write_print_log(f"GDI print SUCCESS → {printer_name}")
+        _write_print_log(f"GDI print SUCCESS → {printer_name} ({copies} cop{'y' if copies==1 else 'ies'} in 1 job)")
         return True
 
     except ImportError as ie:
@@ -291,15 +296,16 @@ def _print_pdf_windows(file_path, printer_name):
     return False
 
 
-def print_to_printer(printer_name, file_path):
+def print_to_printer(printer_name, file_path, copies=1):
     """
     Print file to printer (cross-platform).
-    Uses SumatraPDF for silent printing on Windows.
+    Uses pymupdf+GDI for silent printing on Windows with all copies in one job.
-    
+
     Args:
         printer_name (str): Name of printer or "PDF" for PDF output
         file_path (str): Path to file to print
-        
+        copies (int): Number of copies to print in a single print job
+
     Returns:
         bool: True if successful
     """
@@ -320,7 +326,7 @@ def print_to_printer(printer_name, file_path):
             # Windows: Print PDF using Python GDI (pymupdf + win32print).
             # No external viewer is launched at any point.
             if file_path.endswith('.pdf'):
-                return _print_pdf_windows(file_path, printer_name)
+                return _print_pdf_windows(file_path, printer_name, copies=copies)
             else:
                 subprocess.run(['notepad', '/p', file_path],
                                check=False,
@@ -344,20 +350,23 @@ def print_to_printer(printer_name, file_path):
         return True
 
 
-def print_label_standalone(value, printer, preview=0, svg_template=None):
+def print_label_standalone(value, printer, preview=0, svg_template=None, copies=1):
     """
     Generate a PDF label, save it to pdf_backup/, and print it on the printer.
-    The printer's own paper size and orientation settings are used as-is.
+    All copies are sent in a single print job to avoid blank labels on thermal
+    printers that eject a label between separate jobs.
 
     Args:
         value (str): Label data in format "article;nr_art;serial;status"
         printer (str): Printer name (or "PDF" to skip physical printing)
         preview (int): 0 = print immediately; 1-3 = 3 s delay; >3 = 5 s delay
         svg_template (str): Path to SVG template (optional; auto-selected if None)
+        copies (int): Number of copies to print in one job (default 1)
 
     Returns:
         bool: True if sending to printer succeeded, False otherwise
     """
+    copies = max(1, int(copies))
     pdf_file = None
     try:
         # Step 1 – Generate and save PDF to pdf_backup/
@@ -388,9 +397,9 @@ def print_label_standalone(value, printer, preview=0, svg_template=None):
                 print("\nCancelled by user")
                 return False
 
-        # Step 3 – Send to printer
+        # Step 3 – Send to printer (all copies in one job)
-        print("Sending to printer...")
+        print(f"Sending to printer ({copies} cop{'y' if copies==1 else 'ies'})...")
-        return print_to_printer(printer, pdf_file)
+        return print_to_printer(printer, pdf_file, copies=copies)
 
     except Exception as e:
         print(f"Error printing label: {str(e)}")