frappe-syntax-print（frappe 语法打印）

Frappe Print Formats & PDF Generation

Deterministic reference for print formats, Letter Head, and PDF generation in Frappe v14/v15/v16.

When to Use This Skill

USE when:

• Creating or modifying Print Formats (Jinja or JS)
• Generating PDFs programmatically (get_pdf, download endpoints)
• Configuring Letter Head (header/footer) for print output
• Working with Print Designer (v15+)
• Implementing page breaks, print CSS, or landscape layouts
• Building Report Print Formats ({%= %} syntax)

DO NOT USE for:

• General Jinja template syntax (emails, portals) -- see frappe-syntax-jinja
• Client Script UI logic -- see frappe-syntax-clientscripts
• Web views or portal pages -- see frappe-syntax-jinja

Decision Tree: Which Print Format Type?

Need a printable/PDF document?
├─ YES → Is it a Query/Script Report?
│        ├─ YES → Use JS Template ({%= %} microtemplate)
│        │        Set print_format_for = "Report"
│        └─ NO  → Need visual drag-and-drop editor?
│                  ├─ YES → On v15+?
│                  │        ├─ YES → Use Print Designer (WeasyPrint)
│                  │        └─ NO  → NOT available on v14. Use Jinja.
│                  └─ NO  → Need full layout control?
│                           ├─ YES → Use Jinja Print Format (custom_format=1)
│                           └─ NO  → Use Standard Print Format (auto layout)
└─ NO  → This skill does not apply.

Print Format Types

Standard Print Format

ALWAYS the default. Frappe auto-generates layout from DocType fields. No code needed. Controlled via Print Settings and field print_hide property.

Jinja Print Format

Set custom_format = 1 on the Print Format document. Full Jinja2 with server-side rendering.

Context variables available in every Jinja Print Format:

Example — Minimal Jinja Print Format:

<h1>{{ doc.name }}</h1>
<p>Customer: {{ doc.customer_name }}</p>
<p>Date: {{ doc.posting_date | global_date_format }}</p>

<table class="table table-bordered">
  <thead>
    <tr><th>Item</th><th>Qty</th><th>Rate</th><th>Amount</th></tr>
  </thead>
  <tbody>
    {% for row in doc.items %}
    <tr>
      <td>{{ row.item_name }}</td>
      <td>{{ row.qty }}</td>
      <td>{{ frappe.utils.fmt_money(row.rate, currency=doc.currency) }}</td>
      <td>{{ frappe.utils.fmt_money(row.amount, currency=doc.currency) }}</td>
    </tr>
    {% endfor %}
  </tbody>
</table>

<p><strong>Grand Total:</strong> {{ frappe.utils.fmt_money(doc.grand_total, currency=doc.currency) }}</p>

JS Template (Report Print Formats)

ONLY for Query Reports and Script Reports. Uses {%= %} microtemplate syntax, NOT Jinja.

// In report's .js file
{%= row.item_name %}
{% if (row.qty > 10) { %}
  <strong>Bulk order</strong>
{% } %}

{% for (var i = 0; i < rows.length; i++) { %}
  <tr>
    <td>{%= rows[i].item_name %}</td>
    <td>{%= rows[i].qty %}</td>
  </tr>
{% } %}

CRITICAL: NEVER mix Jinja {{}} and JS {%= %} syntax. They are completely separate template engines.

Print Designer (v15+ Only)

• Separate app: bench get-app print_designer
• Uses WeasyPrint (not wkhtmltopdf)
• Visual drag-and-drop builder in the browser
• NEVER attempt to use Print Designer on v14 -- it does not exist

Letter Head

Letter Head provides consistent header/footer across all print formats.

Configuration

IMPORTANT: The footer field only displays in PDF output, never in browser print preview.

Letter Head in Jinja Templates

# Server-side: render Letter Head programmatically
from frappe.utils.print_format import render_letterhead_for_print

letterhead_html = render_letterhead_for_print(
    letter_head_name="My Company",
    doc=doc
)

Dynamic Letter Head Content

Letter Head content and footer fields support Jinja with doc context:

<!-- In Letter Head content field -->
<div style="text-align: right;">
  <strong>{{ doc.company }}</strong><br>
  Date: {{ doc.posting_date | global_date_format }}
</div>

PDF Generation API

See references/pdf-api.md for complete API reference.

Quick Reference

# Generate PDF bytes from HTML
from frappe.utils.pdf import get_pdf
pdf_bytes = get_pdf(html_string, options=None)

# Generate PDF from a specific document + print format
from frappe.utils.print_format import download_pdf
download_pdf(doctype, name, format=None, doc=None, no_letterhead=0)

Download Endpoints

# Single document PDF
GET /api/method/frappe.utils.print_format.download_pdf
    ?doctype=Sales Invoice
    &name=SINV-00001
    &format=My Print Format
    &no_letterhead=0

# Multiple documents in one PDF
GET /api/method/frappe.utils.print_format.download_multi_pdf
    ?doctype=Sales Invoice
    &name=["SINV-00001","SINV-00002"]
    &format=My Print Format

PDF Engine Selection (v15+)

ALWAYS use wkhtmltopdf on v14. On v15+, Chrome produces better CSS3 support.

Page Breaks & Print CSS

Page Break Classes

<!-- Force page break after this element -->
<div class="page-break"></div>

<!-- Or use CSS directly -->
<div style="page-break-after: always;"></div>

<!-- Page break before -->
<div style="page-break-before: always;"></div>

Print CSS Classes (Frappe Built-in)

PDF Header/Footer HTML

# In hooks.py — inject header/footer into every PDF
pdf_header_html = "myapp.utils.get_pdf_header"
pdf_body_html = "myapp.utils.get_pdf_body"
pdf_footer_html = "myapp.utils.get_pdf_footer"

<!-- Header/footer elements in print format HTML -->
<div id="header-html">
  <span class="page"></span> of <span class="topage"></span>
</div>

<div id="footer-html">
  <p style="text-align: center; font-size: 9px;">
    Printed on {{ frappe.utils.nowdate() }}
  </p>
</div>

Print CSS Best Practices

/* ALWAYS use relative units for print widths */
@media print {
  .print-format {
    max-width: 100%;
    margin: 0;
    padding: 15mm;
  }

  /* Prevent table rows from splitting across pages */
  tr {
    page-break-inside: avoid;
  }

  /* Constrain images */
  img {
    max-width: 100%;
    height: auto;
  }
}

Custom App Print Formats

Ship a Print Format with Your App

myapp/
└── mymodule/
    └── print_format/
        └── my_custom_format/
            ├── my_custom_format.json   # Print Format doc
            └── my_custom_format.html   # Jinja template

In the JSON file, ALWAYS set:

{
  "doctype": "Print Format",
  "name": "My Custom Format",
  "doc_type": "Sales Invoice",
  "module": "My Module",
  "standard": "Yes",
  "custom_format": 1,
  "print_format_type": "Jinja"
}

ALWAYS set standard = "Yes" and module for app-shipped print formats. This ensures they are recognized as part of the app and not as site-level customizations.

Jinja Filters for Print Formats

Register Custom Jinja Filters/Methods

# In hooks.py
jinja = {
    "methods": [
        "myapp.utils.jinja.my_custom_method"
    ],
    "filters": [
        "myapp.utils.jinja.my_custom_filter"
    ]
}

# myapp/utils/jinja.py
def my_custom_method(value):
    """Available as {{ my_custom_method(doc.field) }} in templates."""
    return value.upper()

def my_custom_filter(value, arg=None):
    """Available as {{ doc.field | my_custom_filter }} in templates."""
    return f"[{value}]"

Version Compatibility Matrix

Common Anti-Patterns

See references/anti-patterns.md for the complete list with fixes.

1. NEVER use {{}} in Report Print Formats -- they use {%= %} (JS microtemplate)
2. NEVER call frappe.get_doc() inside a {% for %} loop in templates -- causes N+1 queries
3. NEVER put heavy business logic in Jinja templates -- move to Python and pass results
4. NEVER hardcode page dimensions in CSS -- use .print-format class or relative units
5. NEVER ignore the no_letterhead parameter when generating PDFs programmatically
6. NEVER use Print Designer on v14 -- it requires v15+
7. NEVER embed large base64 images in print templates -- use URLs with max-width: 100%

Reference Files

• Jinja Print Formats -- Jinja syntax, variables, filters, macros
• PDF API -- get_pdf(), download endpoints, page breaks, hooks
• Anti-Patterns -- Common print format mistakes with fixes