resolve camara scan stream failure

- Implement /student_card_class_barcode_download route to filter student cards by class
- Dynamically extract unique class names from the database for frontend selection
- Update student_cards_admin.html to replace the text input with a class selection dropdown

Web/app.py

@@ -2177,7 +2177,7 @@ def _upload_student_cards_excel():
     client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
     try:
         db = client[cfg.MONGODB_DB]
-        student_cards = db['student_cards']
+        student_cards = list(db['student_cards'].find())
         existing_ids.update(
             str(card.get('AusweisId', '')).strip().upper()
             for card in student_cards.find({}, {'AusweisId': 1})
@@ -4108,20 +4108,21 @@ def student_cards_admin():
                         app.logger.error(f"Error adding student card: {e}")
                         flash('Fehler beim Hinzufügen des Ausweises.', 'error')
 
-    # Get all student cards
+    # Get all student cards and decrypt them
     all_cards = list(student_cards.find().sort('AusweisId', 1))
     all_cards = [_decrypt_student_card_doc(card) for card in all_cards]
     client.close()
 
+    raw_classes = set(card.get('Klasse', '').strip() for card in all_cards if card.get('Klasse'))
+    available_classes = sorted(list(raw_classes))
+
     return render_template(
         'student_cards_admin.html',
-        username=session['username'],
-        student_cards=all_cards,
+        student_cards=all_cards,  # Hier all_cards übergeben
         edit_mode=edit_mode,
         form_data=form_data,
-        config={'default': cfg.STUDENT_DEFAULT_BORROW_DAYS},
-        library_module_enabled=cfg.MODULES.is_enabled('library'),
-        student_cards_module_enabled=cfg.MODULES.is_enabled('student_cards')
+        available_classes=available_classes, # Enthält nun die lesbaren Klassen
+        config=cfg.get_school_info()
     )
 
 
@@ -4202,7 +4203,7 @@ def student_card_barcode_download():
     if 'username' not in session:
         return redirect(url_for('login'))
     current_permissions = us.get_effective_permissions(session['username'])
-        
+
     if not current_permissions['actions'].get('can_manage_users', False):
         flash('Ihnen fehlen die nötigen Berechtigungen, um diese Aktion auszuführen.', 'error')
         return redirect(url_for('library_view'))
@@ -4215,12 +4216,13 @@ def student_card_barcode_download():
         from reportlab.pdfgen import canvas
         from reportlab.lib.units import mm
         from reportlab.lib.colors import HexColor, white, black
+        from reportlab.pdfbase.pdfmetrics import stringWidth
         from io import BytesIO
         import barcode
         from barcode.writer import ImageWriter
         import tempfile
         import os
-        
+
         client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
         db = client[cfg.MONGODB_DB]
         student_cards = db['student_cards']
@@ -4230,7 +4232,7 @@ def student_card_barcode_download():
 
         pdf_buffer = BytesIO()
         c = canvas.Canvas(pdf_buffer, pagesize=A4)
-        
+
         page_width, page_height = A4
         margin = 10 * mm
         card_width = 88 * mm
@@ -4242,130 +4244,144 @@ def student_card_barcode_download():
         y_start = page_height - margin
         y_pos = y_start
         col_idx = 0
-        
+
         # Professional color palette
         header_color = HexColor("#0F172A")  # Sehr dunkles blau
         accent_color = HexColor("#2563EB")  # Helles blau
-        light_bg = HexColor("#F8FAFC")      # Sehr heller grau
-        card_bg_color = HexColor("#FFFFFF") # Weiß
-        text_dark = HexColor("#1E293B")     # Dunkler text
-        text_gray = HexColor("#64748B")     # Grauer text
-        
+        light_bg = HexColor("#F8FAFC")  # Sehr heller grau
+        card_bg_color = HexColor("#FFFFFF")  # Weiß
+        text_dark = HexColor("#1E293B")  # Dunkler text
+        text_gray = HexColor("#64748B")  # Grauer text
+
         for i, card in enumerate(all_cards):
             if col_idx == 0 and i > 0:
                 y_pos -= (card_height + gap_y)
-            
+
             # New page if needed
             if y_pos - card_height < margin:
                 c.showPage()
                 y_pos = y_start
                 col_idx = 0
-            
+
             x_pos = x_positions[col_idx]
-            
+
             # Card shadow effect (unter border)
             c.setFillColor(HexColor("#E2E8F0"))
-            c.rect(x_pos + 0.5*mm, y_pos - card_height - 0.5*mm, card_width, card_height, fill=1, stroke=0)
-            
+            c.rect(x_pos + 0.5 * mm, y_pos - card_height - 0.5 * mm, card_width, card_height, fill=1, stroke=0)
+
             # Card background
             c.setLineWidth(1)
             c.setFillColor(card_bg_color)
             c.setStrokeColor(HexColor("#CBD5E1"))
             c.rect(x_pos, y_pos - card_height, card_width, card_height, fill=1, stroke=1)
-            
+
             # Left info section (38mm)
             info_width = 38 * mm
             c.setFillColor(light_bg)
             c.rect(x_pos, y_pos - card_height, info_width, card_height, fill=1, stroke=0)
-            
+
             # Header bar
             c.setFillColor(header_color)
-            c.rect(x_pos, y_pos - 10*mm, card_width, 10*mm, fill=1, stroke=0)
-            
+            c.rect(x_pos, y_pos - 10 * mm, card_width, 10 * mm, fill=1, stroke=0)
+
             # Header accent line
             c.setStrokeColor(accent_color)
             c.setLineWidth(2)
-            c.line(x_pos, y_pos - 10*mm, x_pos + card_width, y_pos - 10*mm)
-            
+            c.line(x_pos, y_pos - 10 * mm, x_pos + card_width, y_pos - 10 * mm)
 
             school_name = cfg.get_school_info()
-            school_name = school_name["name"]
-            # "SCHÜLERAUSWEIS" text in header
-            c.setFont("Helvetica-Bold", 9)
+            school_name_str = str(school_name["name"])
+
+            # Zwei-Zeilen-Header: 1. BIBLIOTHEKSAUSWEIS, 2. Schulname (dynamisch)
+            c.setFont("Helvetica-Bold", 8)
             c.setFillColor(white)
-            c.drawString(x_pos + 3*mm, y_pos - 6.5*mm, f"BIBLIOTHEKSAUSWEIS - {str(school_name)}")
-            
+            c.drawString(x_pos + 3 * mm, y_pos - 4 * mm, "BIBLIOTHEKSAUSWEIS")
+
+            # Dynamische Anpassung des Schulnamens an die Breite
+            font_size = 8
+            while stringWidth(school_name_str, "Helvetica-Bold", font_size) > (card_width - 6 * mm) and font_size > 4:
+                font_size -= 0.5
+
+            c.setFont("Helvetica-Bold", font_size)
+            c.drawString(x_pos + 3 * mm, y_pos - 8 * mm, school_name_str)
+
             # Student name - large and bold
             c.setFillColor(text_dark)
             c.setFont("Helvetica-Bold", 10)
             name = card['SchülerName'][:20]
-            c.drawString(x_pos + 3*mm, y_pos - 14*mm, name)
-            
+            c.drawString(x_pos + 3 * mm, y_pos - 16 * mm, name)
+
             # ID with label
             c.setFont("Helvetica", 8)
             c.setFillColor(text_gray)
-            c.drawString(x_pos + 3*mm, y_pos - 18*mm, "Ausweis ID:")
+            c.drawString(x_pos + 3 * mm, y_pos - 20 * mm, "Ausweis ID:")
             c.setFillColor(text_dark)
             c.setFont("Helvetica-Bold", 9)
-            c.drawString(x_pos + 3*mm, y_pos - 21*mm, str(card['AusweisId']))
-            
+            c.drawString(x_pos + 3 * mm, y_pos - 23 * mm, str(card['AusweisId']))
+
             # Class with label
             if card.get('Klasse'):
                 c.setFont("Helvetica", 8)
                 c.setFillColor(text_gray)
-                c.drawString(x_pos + 3*mm, y_pos - 25*mm, "Klasse:")
+                c.drawString(x_pos + 3 * mm, y_pos - 27 * mm, "Klasse:")
                 c.setFillColor(text_dark)
                 c.setFont("Helvetica-Bold", 9)
-                c.drawString(x_pos + 3*mm, y_pos - 28*mm, card['Klasse'])
-                c.drawString(x_pos + 3*mm, y_pos - 31*mm, "-")
-                c.drawString(x_pos + 3*mm, y_pos - 34*mm, "-")
-                c.drawString(x_pos + 3*mm, y_pos - 37*mm, "-")
-                c.drawString(x_pos + 3*mm, y_pos - 40*mm, "-")
+                c.drawString(x_pos + 3 * mm, y_pos - 30 * mm, card['Klasse'])
+                c.drawString(x_pos + 3 * mm, y_pos - 33 * mm, "-")
+                c.drawString(x_pos + 3 * mm, y_pos - 36 * mm, "-")
+                c.drawString(x_pos + 3 * mm, y_pos - 39 * mm, "-")
+                c.drawString(x_pos + 3 * mm, y_pos - 42 * mm, "-")
 
             # Right barcode section with border highlight
-            barcode_x_start = x_pos + info_width + 1*mm
+            barcode_x_start = x_pos + info_width + 1 * mm
             c.setFillColor(accent_color)
             c.setLineWidth(0)
-            c.rect(barcode_x_start - 1*mm, y_pos - card_height, 
-                   card_width - info_width + 1*mm, 2*mm, fill=1, stroke=0)
-            
-            # Generate and add larger barcode
+            c.rect(barcode_x_start - 1 * mm, y_pos - card_height,
+                   card_width - info_width + 1 * mm, 2 * mm, fill=1, stroke=0)
+
+            # Generate and add dynamically sized barcode
             try:
                 temp_dir = tempfile.gettempdir()
                 barcode_path = os.path.join(temp_dir, f"barcode_{card['AusweisId']}")
-                
-                # Generate barcode with higher module width for better scanning
+
+                # ImageWriter Settings für maximalen Platz und Lesbarkeit
+                options = {
+                    'write_text': False,  # Text entfernen (spart Platz)
+                    'quiet_zone': 1.0,  # Minimaler Rand
+                    'dpi': 300  # Hohe Auflösung
+                }
+
                 barcode_obj = barcode.get('code128', str(card['AusweisId']), writer=ImageWriter())
-                barcode_obj.save(barcode_path)
+                barcode_obj.save(barcode_path, options=options)
                 barcode_file = f"{barcode_path}.png"
-                
+
                 if os.path.exists(barcode_file):
-                    # Larger barcode taking up most of right section
-                    barcode_width = (card_width - info_width - 4*mm)
-                    barcode_height = 16*mm
-                    barcode_y = y_pos - card_height + (card_height - barcode_height) / 2 + 2*mm
-                    
-                    c.drawImage(barcode_file, 
-                               barcode_x_start + 1*mm, 
-                               barcode_y, 
-                               width=barcode_width, 
-                               height=barcode_height, 
-                               preserveAspectRatio=True)
+                    # Barcode über den fast kompletten restlichen Bereich strecken
+                    barcode_width = (card_width - info_width - 4 * mm)
+                    barcode_height = card_height - 15 * mm
+                    barcode_y = y_pos - card_height + 2.5 * mm
+
+                    c.drawImage(barcode_file,
+                                barcode_x_start + 1 * mm,
+                                barcode_y,
+                                width=barcode_width,
+                                height=barcode_height,
+                                preserveAspectRatio=False)  # Strecken erlauben für maximalen Scanbereich
                     os.remove(barcode_file)
                 else:
                     raise Exception("Barcode file not created")
             except Exception as e:
                 c.setFont("Helvetica", 7)
                 c.setFillColor(HexColor("#DC2626"))
-                c.drawString(barcode_x_start + 2*mm, y_pos - card_height + 20*mm, "⚠️ Barcode Error")
-            
+                c.drawString(barcode_x_start + 2 * mm, y_pos - card_height + 20 * mm, "⚠️ Barcode Error")
+
             col_idx += 1
             if col_idx >= cols:
                 col_idx = 0
-        
+
         c.save()
         pdf_buffer.seek(0)
-        
+
         return send_file(
             pdf_buffer,
             mimetype='application/pdf',
@@ -4378,6 +4394,196 @@ def student_card_barcode_download():
         return redirect(url_for('student_cards_admin'))
 
 
+@app.route('/student_card_class_barcode_download', methods=['GET'])
+def student_card_class_barcode_download():
+    """
+    Download PDF with student card barcodes filtered by a specific class from dropdown.
+    """
+    from flask import request, session, redirect, url_for, send_file, flash
+
+    if 'username' not in session:
+        return redirect(url_for('login'))
+
+    current_permissions = us.get_effective_permissions(session['username'])
+    if not current_permissions['actions'].get('can_manage_users', False):
+        flash('Ihnen fehlen die nötigen Berechtigungen, um diese Aktion auszuführen.', 'error')
+        return redirect(url_for('library_view'))
+
+    class_name = request.args.get('class_name', '').strip()
+    if not class_name:
+        flash('Bitte wählen Sie eine Klasse aus.', 'error')
+        return redirect(url_for('student_cards_admin'))
+
+    try:
+        from reportlab.lib.pagesizes import A4
+        from reportlab.pdfgen import canvas
+        from reportlab.lib.units import mm
+        from reportlab.lib.colors import HexColor, white
+        from reportlab.pdfbase.pdfmetrics import stringWidth
+        from io import BytesIO
+        import barcode
+        from barcode.writer import ImageWriter
+        import tempfile
+        import os
+        import datetime
+
+        client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
+        db = client[cfg.MONGODB_DB]
+        student_cards = db['student_cards']
+
+        # 1. Alle Ausweise laden
+        all_cards = list(student_cards.find().sort('AusweisId', 1))
+        client.close()
+
+        # 2. Alle entschlüsseln
+        decrypted_cards = [_decrypt_student_card_doc(card) for card in all_cards]
+        
+        # 3. Im Speicher nach der Klartext-Klasse filtern
+        class_cards = [
+            card for card in decrypted_cards 
+            if card.get('Klasse', '').strip() == class_name
+        ]
+
+        if not class_cards:
+            flash(f'Keine Ausweise für die Klasse "{class_name}" gefunden.', 'error')
+            return redirect(url_for('student_cards_admin'))
+
+        pdf_buffer = BytesIO()
+        c = canvas.Canvas(pdf_buffer, pagesize=A4)
+
+        page_width, page_height = A4
+        margin = 10 * mm
+        card_width = 88 * mm
+        card_height = 56 * mm
+        cols = 2
+        gap_x = 8 * mm
+        gap_y = 8 * mm
+        x_positions = [margin, margin + card_width + gap_x]
+        y_start = page_height - margin
+        y_pos = y_start
+        col_idx = 0
+
+        header_color = HexColor("#0F172A")
+        accent_color = HexColor("#2563EB")
+        light_bg = HexColor("#F8FAFC")
+        card_bg_color = HexColor("#FFFFFF")
+        text_dark = HexColor("#1E293B")
+        text_gray = HexColor("#64748B")
+
+        for i, card in enumerate(class_cards):
+            if col_idx == 0 and i > 0:
+                y_pos -= (card_height + gap_y)
+
+            if y_pos - card_height < margin:
+                c.showPage()
+                y_pos = y_start
+                col_idx = 0
+
+            x_pos = x_positions[col_idx]
+
+            c.setFillColor(HexColor("#E2E8F0"))
+            c.rect(x_pos + 0.5 * mm, y_pos - card_height - 0.5 * mm, card_width, card_height, fill=1, stroke=0)
+
+            c.setLineWidth(1)
+            c.setFillColor(card_bg_color)
+            c.setStrokeColor(HexColor("#CBD5E1"))
+            c.rect(x_pos, y_pos - card_height, card_width, card_height, fill=1, stroke=1)
+
+            info_width = 38 * mm
+            c.setFillColor(light_bg)
+            c.rect(x_pos, y_pos - card_height, info_width, card_height, fill=1, stroke=0)
+
+            c.setFillColor(header_color)
+            c.rect(x_pos, y_pos - 10 * mm, card_width, 10 * mm, fill=1, stroke=0)
+
+            c.setStrokeColor(accent_color)
+            c.setLineWidth(2)
+            c.line(x_pos, y_pos - 10 * mm, x_pos + card_width, y_pos - 10 * mm)
+
+            school_name = cfg.get_school_info()
+            school_name_str = str(school_name["name"])
+
+            c.setFont("Helvetica-Bold", 8)
+            c.setFillColor(white)
+            c.drawString(x_pos + 3 * mm, y_pos - 4 * mm, "BIBLIOTHEKSAUSWEIS")
+
+            font_size = 8
+            while stringWidth(school_name_str, "Helvetica-Bold", font_size) > (card_width - 6 * mm) and font_size > 4:
+                font_size -= 0.5
+
+            c.setFont("Helvetica-Bold", font_size)
+            c.drawString(x_pos + 3 * mm, y_pos - 8 * mm, school_name_str)
+
+            c.setFillColor(text_dark)
+            c.setFont("Helvetica-Bold", 10)
+            name = card.get('SchülerName', '')[:20]
+            c.drawString(x_pos + 3 * mm, y_pos - 16 * mm, name)
+
+            c.setFont("Helvetica", 8)
+            c.setFillColor(text_gray)
+            c.drawString(x_pos + 3 * mm, y_pos - 20 * mm, "Ausweis ID:")
+            c.setFillColor(text_dark)
+            c.setFont("Helvetica-Bold", 9)
+            c.drawString(x_pos + 3 * mm, y_pos - 23 * mm, str(card.get('AusweisId', '')))
+
+            if card.get('Klasse'):
+                c.setFont("Helvetica", 8)
+                c.setFillColor(text_gray)
+                c.drawString(x_pos + 3 * mm, y_pos - 27 * mm, "Klasse:")
+                c.setFillColor(text_dark)
+                c.setFont("Helvetica-Bold", 9)
+                c.drawString(x_pos + 3 * mm, y_pos - 30 * mm, card['Klasse'])
+
+            barcode_x_start = x_pos + info_width + 1 * mm
+            c.setFillColor(accent_color)
+            c.setLineWidth(0)
+            c.rect(barcode_x_start - 1 * mm, y_pos - card_height, card_width - info_width + 1 * mm, 2 * mm, fill=1,
+                   stroke=0)
+
+            try:
+                temp_dir = tempfile.gettempdir()
+                barcode_path = os.path.join(temp_dir, f"barcode_{card.get('AusweisId', i)}")
+
+                options = {
+                    'write_text': False,
+                    'quiet_zone': 1.0,
+                    'dpi': 300
+                }
+
+                barcode_obj = barcode.get('code128', str(card.get('AusweisId', '')), writer=ImageWriter())
+                barcode_obj.save(barcode_path, options=options)
+                barcode_file = f"{barcode_path}.png"
+
+                if os.path.exists(barcode_file):
+                    barcode_width = (card_width - info_width - 4 * mm)
+                    barcode_height = card_height - 15 * mm
+                    barcode_y = y_pos - card_height + 2.5 * mm
+
+                    c.drawImage(barcode_file, barcode_x_start + 1 * mm, barcode_y,
+                                width=barcode_width, height=barcode_height, preserveAspectRatio=False)
+                    os.remove(barcode_file)
+            except Exception as e:
+                pass
+
+            col_idx += 1
+            if col_idx >= cols:
+                col_idx = 0
+
+        c.save()
+        pdf_buffer.seek(0)
+
+        filename = f'ausweise_klasse_{class_name.replace(" ", "_")}_{datetime.datetime.now().strftime("%Y%m%d")}.pdf'
+
+        return send_file(
+            pdf_buffer,
+            mimetype='application/pdf',
+            as_attachment=True,
+            download_name=filename
+        )
+    except Exception as e:
+        flash('Fehler beim PDF-Download', 'error')
+        return redirect(url_for('student_cards_admin'))
+
 @app.route('/student_card_single_barcode_download/<card_id>', methods=['GET'])
 def student_card_single_barcode_download(card_id):
     """
@@ -4386,7 +4592,7 @@ def student_card_single_barcode_download(card_id):
     if 'username' not in session:
         return redirect(url_for('login'))
     current_permissions = us.get_effective_permissions(session['username'])
-        
+
     if not current_permissions['actions'].get('can_manage_users', False):
         flash('Ihnen fehlen die nötigen Berechtigungen, um diese Aktion auszuführen.', 'error')
         return redirect(url_for('library_view'))
@@ -4399,148 +4605,165 @@ def student_card_single_barcode_download(card_id):
         from reportlab.pdfgen import canvas
         from reportlab.lib.units import mm
         from reportlab.lib.colors import HexColor, white, black
+        from reportlab.pdfbase.pdfmetrics import stringWidth
         from io import BytesIO
         from bson.objectid import ObjectId
         import barcode
         from barcode.writer import ImageWriter
         import tempfile
         import os
-        
+
         client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
         db = client[cfg.MONGODB_DB]
         student_cards = db['student_cards']
         card = student_cards.find_one({'_id': ObjectId(card_id)})
         card = _decrypt_student_card_doc(card)
         client.close()
-        
+
         if not card:
             flash('Ausweis nicht gefunden.', 'error')
             return redirect(url_for('student_cards_admin'))
 
         pdf_buffer = BytesIO()
         c = canvas.Canvas(pdf_buffer, pagesize=A4)
-        
+
         page_width, page_height = A4
-        margin = 20 * mm
         card_width = 105 * mm
         card_height = 70 * mm
         x_pos = (page_width - card_width) / 2
-        y_pos = (page_height - card_height) / 2
-        
+
+        # Korrektur des y_pos auf die OBERKANTE, damit die nachfolgenden Rechnungen bündig sind
+        y_pos = (page_height + card_height) / 2
+
         # Professional color palette
-        header_color = HexColor("#0F172A")  # Sehr dunkles blau
-        accent_color = HexColor("#2563EB")  # Helles blau
-        light_bg = HexColor("#F8FAFC")      # Sehr heller grau
-        card_bg_color = HexColor("#FFFFFF") # Weiß
-        text_dark = HexColor("#1E293B")     # Dunkler text
-        text_gray = HexColor("#64748B")     # Grauer text
-        
+        header_color = HexColor("#0F172A")
+        accent_color = HexColor("#2563EB")
+        light_bg = HexColor("#F8FAFC")
+        card_bg_color = HexColor("#FFFFFF")
+        text_dark = HexColor("#1E293B")
+        text_gray = HexColor("#64748B")
+
         # Card shadow effect
         c.setFillColor(HexColor("#E2E8F0"))
-        c.rect(x_pos + 1*mm, y_pos - card_height - 1*mm, card_width, card_height, fill=1, stroke=0)
-        
+        c.rect(x_pos + 1 * mm, y_pos - card_height - 1 * mm, card_width, card_height, fill=1, stroke=0)
+
         # Card background
         c.setLineWidth(1.5)
         c.setFillColor(card_bg_color)
         c.setStrokeColor(HexColor("#CBD5E1"))
-        c.rect(x_pos, y_pos, card_width, card_height, fill=1, stroke=1)
-        
+        c.rect(x_pos, y_pos - card_height, card_width, card_height, fill=1, stroke=1)
+
         # Left info section (50mm)
         info_width = 50 * mm
         c.setFillColor(light_bg)
         c.rect(x_pos, y_pos - card_height, info_width, card_height, fill=1, stroke=0)
-        
+
         # Vertical divider line
         c.setStrokeColor(accent_color)
         c.setLineWidth(3)
         c.line(x_pos + info_width, y_pos - card_height, x_pos + info_width, y_pos)
-        
+
         # Header bar
         c.setFillColor(header_color)
-        c.rect(x_pos, y_pos - 10*mm, card_width, 10*mm, fill=1, stroke=0)
-        
+        c.rect(x_pos, y_pos - 10 * mm, card_width, 10 * mm, fill=1, stroke=0)
+
         # Header accent line
         c.setStrokeColor(accent_color)
         c.setLineWidth(2.5)
-        c.line(x_pos, y_pos - 10*mm, x_pos + card_width, y_pos - 10*mm)
-        
+        c.line(x_pos, y_pos - 10 * mm, x_pos + card_width, y_pos - 10 * mm)
+
         school_name = cfg.get_school_info()
-        school_name = school_name["name"]
-        # "SCHÜLERAUSWEIS" text in header
-        c.setFont("Helvetica-Bold", 11)
+        school_name_str = str(school_name["name"])
+
+        # Zwei-Zeilen-Header
+        c.setFont("Helvetica-Bold", 10)
         c.setFillColor(white)
-        c.drawString(x_pos + 4*mm, y_pos - 6.5*mm, f"BIBLIOTHEKSAUSWEIS - {str(school_name)}")
-        
+        c.drawString(x_pos + 4 * mm, y_pos - 4.5 * mm, "BIBLIOTHEKSAUSWEIS")
+
+        # Dynamische Größe für den Schulnamen
+        font_size = 10
+        while stringWidth(school_name_str, "Helvetica-Bold", font_size) > (card_width - 8 * mm) and font_size > 4:
+            font_size -= 0.5
+
+        c.setFont("Helvetica-Bold", font_size)
+        c.drawString(x_pos + 4 * mm, y_pos - 8.5 * mm, school_name_str)
+
         # Student name - large and prominent
         c.setFillColor(text_dark)
         c.setFont("Helvetica-Bold", 12)
         name = card['SchülerName'][:25]
-        c.drawString(x_pos + 4*mm, y_pos - 16*mm, name)
-        
+        c.drawString(x_pos + 4 * mm, y_pos - 18 * mm, name)
+
         # ID section with label
         c.setFont("Helvetica", 9)
         c.setFillColor(text_gray)
-        c.drawString(x_pos + 4*mm, y_pos - 21*mm, "Ausweis-ID:")
-        
+        c.drawString(x_pos + 4 * mm, y_pos - 24 * mm, "Ausweis-ID:")
+
         c.setFillColor(text_dark)
         c.setFont("Helvetica-Bold", 11)
-        c.drawString(x_pos + 4*mm, y_pos - 25*mm, str(card['AusweisId']))
-        
+        c.drawString(x_pos + 4 * mm, y_pos - 28 * mm, str(card['AusweisId']))
+
         # Class section
         if card.get('Klasse'):
             c.setFont("Helvetica", 9)
             c.setFillColor(text_gray)
-            c.drawString(x_pos + 4*mm, y_pos - 30*mm, "Klasse:")
-            
+            c.drawString(x_pos + 4 * mm, y_pos - 34 * mm, "Klasse:")
+
             c.setFillColor(text_dark)
             c.setFont("Helvetica-Bold", 11)
-            c.drawString(x_pos + 4*mm, y_pos - 34*mm, card['Klasse'])
-        
+            c.drawString(x_pos + 4 * mm, y_pos - 38 * mm, card['Klasse'])
+
         # Barcode section - right side with blue accent
-        barcode_x_start = x_pos + info_width + 3*mm
+        barcode_x_start = x_pos + info_width + 3 * mm
         c.setFillColor(accent_color)
         c.setLineWidth(0)
-        c.rect(x_pos + info_width, y_pos - card_height, 
-               card_width - info_width, 3*mm, fill=1, stroke=0)
-        
-        # Generate and add large barcode
+        c.rect(x_pos + info_width, y_pos - card_height,
+               card_width - info_width, 3 * mm, fill=1, stroke=0)
+
+        # Generate and add large dynamically sized barcode
         try:
             temp_dir = tempfile.gettempdir()
             barcode_path = os.path.join(temp_dir, f"barcode_{card['AusweisId']}")
-            
-            # Generate barcode with better sizing
+
+            # Options anpassen für Scanbarkeit
+            options = {
+                'write_text': False,
+                'quiet_zone': 1.0,
+                'dpi': 300
+            }
+
             barcode_obj = barcode.get('code128', str(card['AusweisId']), writer=ImageWriter())
-            barcode_obj.save(barcode_path)
+            barcode_obj.save(barcode_path, options=options)
             barcode_file = f"{barcode_path}.png"
-            
+
             if os.path.exists(barcode_file):
-                # Large barcode on right side
-                barcode_width = (card_width - info_width - 8*mm)
-                barcode_height = 20*mm
-                barcode_y_offset = (card_height - 10*mm - barcode_height) / 2
-                
-                c.drawImage(barcode_file, 
-                           barcode_x_start, 
-                           y_pos - card_height + barcode_y_offset + 5*mm, 
-                           width=barcode_width, 
-                           height=barcode_height, 
-                           preserveAspectRatio=True)
+                # Den gesamten Platz auf der rechten Seite ausnutzen
+                barcode_width = (card_width - info_width - 8 * mm)
+                barcode_height = card_height - 18 * mm
+                barcode_y = y_pos - card_height + 5 * mm
+
+                c.drawImage(barcode_file,
+                            barcode_x_start + 1 * mm,
+                            barcode_y,
+                            width=barcode_width,
+                            height=barcode_height,
+                            preserveAspectRatio=False)  # Ausdehnung in alle Richtungen
                 os.remove(barcode_file)
             else:
                 raise Exception("Barcode file not created")
         except Exception as e:
             c.setFont("Helvetica", 9)
             c.setFillColor(HexColor("#DC2626"))
-            c.drawString(barcode_x_start + 2*mm, y_pos - card_height + 25*mm, "⚠️ Barcode Error")
-        
+            c.drawString(barcode_x_start + 2 * mm, y_pos - card_height + 25 * mm, "⚠️ Barcode Error")
+
         # Bottom info line
         c.setStrokeColor(HexColor("#CBD5E1"))
         c.setLineWidth(0.5)
-        c.line(x_pos, y_pos - card_height + 3*mm, x_pos + card_width, y_pos - card_height + 3*mm)
-        
+        c.line(x_pos, y_pos - card_height + 3 * mm, x_pos + card_width, y_pos - card_height + 3 * mm)
+
         c.save()
         pdf_buffer.seek(0)
-        
+
         return send_file(
             pdf_buffer,
             mimetype='application/pdf',
@@ -4552,7 +4775,6 @@ def student_card_single_barcode_download(card_id):
         flash('Fehler beim PDF-Download', 'error')
         return redirect(url_for('student_cards_admin'))
 
-
 @app.route('/login', methods=['GET', 'POST'])
 def login():
     """

Web/templates/library_table.html

@@ -805,71 +805,92 @@
         deleteLibraryItem(itemId);
     }
 
-    // =========================================================================
-    // 3. CORE SCANNER ROUTING ENGINE (QUAGGA2)
-    // =========================================================================
-    function startScanner(targetCallback) {
-        const readerWrap = document.getElementById('scanReaderWrap');
+    async function startScanner(callback = null) {
+        if (scannerRunning) {
+            console.warn("Scanner is already running. Stopping it first...");
+            await stopScanner();
+        }
+
+        activeScannerCallback = callback;
+
+        const scannerWrap = document.querySelector('.library-scan-reader-wrap');
         const toggleBtn = document.getElementById('toggleScannerBtn');
 
-        activeScannerCallback = targetCallback;
+        // 1. CRITICAL FIX: Make the container visible BEFORE Quagga initializes
+        // Quagga cannot calculate video dimensions if display is 'none'
+        if (scannerWrap) {
+            scannerWrap.style.display = 'block';
+        }
 
-        if (readerWrap) readerWrap.style.display = 'block';
-        setScanStatus('Initializing camera...', 'warn');
+        setScanStatus('Starte Kamera...', 'warn');
 
-        Quagga.init({
-            inputStream: {
-                name: "Live",
-                type: "LiveStream",
-                target: document.querySelector('#library-scanner-container'),
-                constraints: {
-                    width: 640,
-                    height: 480,
-                    facingMode: "environment"
+        // 2. Initialize Quagga with a slight delay to allow the DOM to render the block
+        setTimeout(() => {
+            Quagga.init({
+                inputStream: {
+                    name: "Live",
+                    type: "LiveStream",
+                    // This MUST match the inner div where the video should appear
+                    target: document.querySelector('.library-scan-reader'), 
+                    constraints: {
+                        width: 640,
+                        height: 480,
+                        facingMode: "environment" // Prefer back camera on mobile
+                    }
                 },
-            },
-            decoder: {
-                readers: [
-                    "code_128_reader",
-                    "ean_reader",
-                    "code_39_reader",
-                    "upc_reader",
-                    "codabar_reader",
-                    "i2of5_reader"
-                ]
-            }
-        }, function(err) {
-            if (err) {
-                console.error('Scanner start failed:', err);
-                if (readerWrap) readerWrap.style.display = 'none';
-                const detail = (err && (err.message || err.name)) ? ` (${err.message || err.name})` : '';
-                setScanStatus(`Scanner konnte nicht gestartet werden${detail}`, 'error');
-                return;
-            }
+                locator: {
+                    patchSize: "medium",
+                    halfSample: true
+                },
+                decoder: {
+                    // Keep only the barcode types you actually use to improve performance
+                    readers: ["code_128_reader", "ean_reader", "code_39_reader"] 
+                },
+                locate: true
+            }, function(err) {
+                if (err) {
+                    // This will finally log the actual error (e.g., NotAllowedError) if permissions fail
+                    console.error("Quagga initialization failed:", err);
+                    setScanStatus('Kamera-Fehler: ' + (err.name || err), 'error');
 
-            Quagga.start();
-            scannerRunning = true;
+                    if (scannerWrap) scannerWrap.style.display = 'none';
+                    scannerRunning = false;
+                    return;
+                }
 
-            if (!targetCallback && toggleBtn) {
-                toggleBtn.textContent = 'Scanner stoppen';
-            }
-            setScanStatus('Scanner aktiv. Jetzt Code scannen.', 'warn');
-        });
+                Quagga.start();
+                scannerRunning = true;
+                setScanStatus('Scanner bereit.', 'ok');
+
+                if (toggleBtn) {
+                    toggleBtn.textContent = 'Scanner stoppen';
+                }
+            });
+        }, 50);
     }
 
-    function stopScanner() {
+    async function stopScanner() {
         if (!scannerRunning) return;
 
-        const readerWrap = document.getElementById('scanReaderWrap');
-        const toggleBtn = document.getElementById('toggleScannerBtn');
+        try {
+            Quagga.stop();
+        } catch (e) {
+            console.warn("Error stopping Quagga (it may not have been running):", e);
+        }
 
-        Quagga.stop();
         scannerRunning = false;
         activeScannerCallback = null;
 
-        if (readerWrap) readerWrap.style.display = 'none';
-        if (toggleBtn) toggleBtn.textContent = 'Scanner starten';
-        setScanStatus('Scanner gestoppt.', 'warn');
+        // Hide the container to free up UI space
+        const scannerWrap = document.querySelector('.library-scan-reader-wrap');
+        if (scannerWrap) {
+            scannerWrap.style.display = 'none';
+        }
+
+        const toggleBtn = document.getElementById('toggleScannerBtn');
+        if (toggleBtn) {
+            toggleBtn.textContent = 'Kamera Scanner'; // Reset button text
+        }
     }
 
     async function isStudentCardBarcode(code) {

Web/templates/student_cards_admin.html

@@ -232,6 +232,16 @@
             <h1>📚 Bibliotheksausweise (Bibliothek)</h1>
         </div>
         <div class="export-buttons">
+            <form method="GET" action="{{ url_for('student_card_class_barcode_download') }}" style="display: inline-flex; gap: 5px; align-items: center; background: white; padding: 2px; border-radius: 4px; border: 1px solid #ddd;">
+                <select name="class_name" required style="border: none; padding: 8px; outline: none; font-size: 14px; background: transparent; cursor: pointer;">
+                    <option value="" disabled selected>-- Klasse wählen --</option>
+                    {% for cls in available_classes %}
+                        <option value="{{ cls }}">{{ cls }}</option>
+                    {% endfor %}
+                </select>
+                <button type="submit" class="btn-print" style="background: #17a2b8; padding: 8px 12px; margin: 0;">📤 PDF</button>
+            </form>
+
             <a href="{{ url_for('student_card_barcode_download') }}" class="btn-print" style="background: #28a745;">📥 Alle Ausweise (PDF)</a>
             <a href="{{ url_for('library_admin') }}" class="btn btn-primary">← Zur Bibliotheks-Upload</a>
         </div>