quality_app-v2/documentation/PRINTING_MODULE_REFERENCE.md

Old Quality App - Printing Module Summary

Key Files

1. /srv/quality_app/py_app/app/pdf_generator.py

Main PDF Generation Engine

The LabelPDFGenerator class handles all label PDF generation:

• Dimensions: 80mm x 105mm thermal printer labels
• Optimized for: Epson TM-T20, Citizen CTS-310 thermal printers

Key Methods:

generate_labels_pdf(order_data, quantity, printer_optimized=True)

• Generates PDF with multiple labels based on quantity
• Creates sequential labels: CP00000711-001, CP00000711-002, etc.
• Returns BytesIO buffer with complete PDF

generate_single_label_pdf(order_data, piece_number, total_pieces, printer_optimized=True)

• Generates single label PDF for specific piece number
• Used by QZ Tray for direct thermal printing
• Returns BytesIO buffer with one label

_draw_label(canvas, order_data, sequential_number, current_num, total_qty)

Label Layout:

• Row 1: Company header (empty)
• Row 2: Customer name
• Row 3: Quantity ordered (left) | Right column split 40/60
• Row 4: Customer order (com_achiz_client - nr_linie_com_client)
• Row 5: Delivery date (data_livrare)
• Row 6: Product description (double height)
• Row 7: Size (dimensiune)
• Row 8: Article code (customer_article_number)
• Row 9: Production order (comanda_productie - sequential_number)

Barcodes:

• Bottom: CODE128 barcode with sequential number (CP00000711/001)
• Right side: CODE128 vertical barcode with customer order format

_optimize_for_label_printer(canvas)

• Sets 300 DPI resolution
• Enables compression
• Sets print scaling to 100% (no scaling)
• Adds PDF metadata for printer optimization

---

2. /srv/quality_app/py_app/app/print_module.py

Database Data Retrieval

Key Functions:

get_unprinted_orders_data(limit=100)

• Returns orders where printed_labels != 1
• Retrieves all fields needed for label generation
• Returns list of order dictionaries

get_printed_orders_data(limit=100)

• Returns orders where printed_labels = 1
• Used for "print lost labels" page
• Returns list of order dictionaries

update_order_printed_status(order_id)

• Updates printed_labels = 1 for order
• Called after successful printing

---

3. API Routes in /srv/quality_app/py_app/app/routes.py

/generate_label_pdf (POST)

Single Label Generation for QZ Tray

Accepts JSON:
{
    "comanda_productie": "CP00000711",
    "cantitate": 5,
    "piece_number": 1,
    "total_pieces": 5,
    ... (other order fields)
}

Returns: PDF binary data
Purpose: Generate single label for thermal printer via QZ Tray

/generate_labels_pdf/<order_id>/true (POST)

Batch Label Generation for PDF Download

Returns: Multi-page PDF with all labels for order
Purpose: Generate all labels for download/preview
Also marks order as printed (printed_labels = 1)

---

4. /srv/quality_app/py_app/app/print_config.py

Print Service Configuration

WINDOWS_PRINT_SERVICE_URL = "http://192.168.1.XXX:8765"
PRINT_SERVICE_TIMEOUT = 30
PRINT_SERVICE_ENABLED = True

Note: Windows print service is configured but QZ Tray is the primary method.

---

Label Printing Flow

For Direct Printing (QZ Tray):

1. User selects order from table
2. Clicks "Print Labels" button
3. Frontend calls /labels/api/generate-pdf with order data and piece_number
4. Backend's LabelPDFGenerator.generate_single_label_pdf() creates PDF
5. Returns PDF binary to frontend
6. QZ Tray prints directly to thermal printer
7. After successful print, calls /labels/api/update-printed-status/{id}

For PDF Download:

1. User selects order
2. Clicks "Generate PDF" button
3. Frontend calls /labels/api/generate-pdf/{orderId}/true
4. Backend's LabelPDFGenerator.generate_labels_pdf() creates multi-page PDF
5. Returns PDF for browser download/print
6. Order marked as printed

---

Key Configuration Classes

LabelPDFGenerator Parameters:

# Label dimensions
label_width = 80mm
label_height = 105mm

# Content area
content_width = 60mm
content_height = 68mm
content_x = 4mm from left
content_y = 22mm from bottom

# Layout
row_height = 6.8mm (content_height / 10)
left_column_width = 40% (24mm)
right_column_width = 60% (36mm)

# Barcode areas
bottom_barcode: 80mm width x 12mm height
vertical_barcode: 12mm width x 68mm height (rotated 90°)

---

Order Data Fields Used

Required fields for label generation:
- comanda_productie: Production order number
- cod_articol: Article code
- descr_com_prod: Product description
- cantitate: Quantity
- com_achiz_client: Customer purchase order
- nr_linie_com_client: Customer order line
- customer_name: Customer name
- customer_article_number: Customer article number
- data_livrare: Delivery date
- dimensiune: Product size
- printed_labels: Status (0 = unprinted, 1 = printed)

---

Thermal Printer Optimization

The PDF generator is specifically optimized for thermal label printers:

1. No margins: Fills entire label area
2. High resolution: 300 DPI quality
3. Monochrome: Black/white only (no colors)
4. Compression: Reduces file size
5. Scaling: 100% (no scaling in printer)
6. Bar width: Optimized for thermal resolution

Tested with:

• Epson TM-T20 (80mm thermal printer)
• Citizen CTS-310 (80mm thermal printer)