feat(student-cards): add class-specific PDF export with dynamic dropdown

- 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

@@ -4113,15 +4113,24 @@ def student_cards_admin():
     all_cards = [_decrypt_student_card_doc(card) for card in all_cards]
     client.close()
 
+    # Alle eindeutigen Klassen für das Dropdown ermitteln
+    client = MongoClient(cfg.MONGODB_HOST, cfg.MONGODB_PORT)
+    db = client[cfg.MONGODB_DB]
+    student_cards_collection = db['student_cards']
+
+    # Extrahiere alle vorhandenen Klassen, entferne leere/None Werte und sortiere sie
+    raw_classes = student_cards_collection.distinct('Klasse')
+    available_classes = sorted([c for c in raw_classes if c])
+
+    client.close()
+
     return render_template(
         'student_cards_admin.html',
-        username=session['username'],
+        student_cards=student_cards,
-        student_cards=all_cards,
         edit_mode=edit_mode,
         form_data=form_data,
-        config={'default': cfg.STUDENT_DEFAULT_BORROW_DAYS},
+        available_classes=available_classes,
-        library_module_enabled=cfg.MODULES.is_enabled('library'),
+        config=cfg.get_school_info()
-        student_cards_module_enabled=cfg.MODULES.is_enabled('student_cards')
     )
 
 
@@ -4215,6 +4224,7 @@ 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
@@ -4246,10 +4256,10 @@ def student_card_barcode_download():
         # Professional color palette
         header_color = HexColor("#0F172A")  # Sehr dunkles blau
         accent_color = HexColor("#2563EB")  # Helles blau
-        light_bg = HexColor("#F8FAFC")      # Sehr heller grau
+        light_bg = HexColor("#F8FAFC")  # Sehr heller grau
-        card_bg_color = HexColor("#FFFFFF") # Weiß
+        card_bg_color = HexColor("#FFFFFF")  # Weiß
-        text_dark = HexColor("#1E293B")     # Dunkler text
+        text_dark = HexColor("#1E293B")  # Dunkler text
-        text_gray = HexColor("#64748B")     # Grauer text
+        text_gray = HexColor("#64748B")  # Grauer text
 
         for i, card in enumerate(all_cards):
             if col_idx == 0 and i > 0:
@@ -4265,7 +4275,7 @@ def student_card_barcode_download():
 
             # 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)
@@ -4280,84 +4290,98 @@ def student_card_barcode_download():
 
             # 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"]
+            school_name_str = str(school_name["name"])
-            # "SCHÜLERAUSWEIS" text in header
+
-            c.setFont("Helvetica-Bold", 9)
+            # 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 - 30 * mm, card['Klasse'])
-                c.drawString(x_pos + 3*mm, y_pos - 31*mm, "-")
+                c.drawString(x_pos + 3 * mm, y_pos - 33 * mm, "-")
-                c.drawString(x_pos + 3*mm, y_pos - 34*mm, "-")
+                c.drawString(x_pos + 3 * mm, y_pos - 36 * mm, "-")
-                c.drawString(x_pos + 3*mm, y_pos - 37*mm, "-")
+                c.drawString(x_pos + 3 * mm, y_pos - 39 * mm, "-")
-                c.drawString(x_pos + 3*mm, y_pos - 40*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, 
+            c.rect(barcode_x_start - 1 * mm, y_pos - card_height,
-                   card_width - info_width + 1*mm, 2*mm, fill=1, stroke=0)
+                   card_width - info_width + 1 * mm, 2 * mm, fill=1, stroke=0)
 
-            # Generate and add larger barcode
+            # 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 über den fast kompletten restlichen Bereich strecken
-                    barcode_width = (card_width - info_width - 4*mm)
+                    barcode_width = (card_width - info_width - 4 * mm)
-                    barcode_height = 16*mm
+                    barcode_height = card_height - 15 * mm
-                    barcode_y = y_pos - card_height + (card_height - barcode_height) / 2 + 2*mm
+                    barcode_y = y_pos - card_height + 2.5 * mm
 
                     c.drawImage(barcode_file,
-                               barcode_x_start + 1*mm, 
+                                barcode_x_start + 1 * mm,
-                               barcode_y, 
+                                barcode_y,
-                               width=barcode_width, 
+                                width=barcode_width,
-                               height=barcode_height, 
+                                height=barcode_height,
-                               preserveAspectRatio=True)
+                                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:
@@ -4378,6 +4402,187 @@ 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']
+
+        class_cards = list(student_cards.find({'Klasse': class_name}).sort('AusweisId', 1))
+        class_cards = [_decrypt_student_card_doc(card) for card in class_cards]
+        client.close()
+
+        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):
     """
@@ -4399,6 +4604,7 @@ 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
@@ -4421,29 +4627,30 @@ def student_card_single_barcode_download(card_id):
         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
+        header_color = HexColor("#0F172A")
-        accent_color = HexColor("#2563EB")  # Helles blau
+        accent_color = HexColor("#2563EB")
-        light_bg = HexColor("#F8FAFC")      # Sehr heller grau
+        light_bg = HexColor("#F8FAFC")
-        card_bg_color = HexColor("#FFFFFF") # Weiß
+        card_bg_color = HexColor("#FFFFFF")
-        text_dark = HexColor("#1E293B")     # Dunkler text
+        text_dark = HexColor("#1E293B")
-        text_gray = HexColor("#64748B")     # Grauer text
+        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
@@ -4457,86 +4664,101 @@ def student_card_single_barcode_download(card_id):
 
         # 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"]
+        school_name_str = str(school_name["name"])
-        # "SCHÜLERAUSWEIS" text in header
+
-        c.setFont("Helvetica-Bold", 11)
+        # 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)
+               card_width - info_width, 3 * mm, fill=1, stroke=0)
 
-        # Generate and add large barcode
+        # 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
+                # Den gesamten Platz auf der rechten Seite ausnutzen
-                barcode_width = (card_width - info_width - 8*mm)
+                barcode_width = (card_width - info_width - 8 * mm)
-                barcode_height = 20*mm
+                barcode_height = card_height - 18 * mm
-                barcode_y_offset = (card_height - 10*mm - barcode_height) / 2
+                barcode_y = y_pos - card_height + 5 * mm
 
                 c.drawImage(barcode_file,
-                           barcode_x_start, 
+                            barcode_x_start + 1 * mm,
-                           y_pos - card_height + barcode_y_offset + 5*mm, 
+                            barcode_y,
-                           width=barcode_width, 
+                            width=barcode_width,
-                           height=barcode_height, 
+                            height=barcode_height,
-                           preserveAspectRatio=True)
+                            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)
@@ -4552,7 +4774,6 @@ 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/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>