Swappable invoice renderers

doc/development/api/index.rst

@@ -10,5 +10,6 @@ Contents:
    exporter
    ticketoutput
    payment
+   invoice
    customview
    general

doc/development/api/invoice.rst

@@ -0,0 +1,95 @@
+.. highlight:: python
+   :linenothreshold: 5
+
+Writing an invoice renderer plugin
+==================================
+
+An invoice renderer controls how invoice files are built.
+The creation of such a plugin is very similar to creating an export output.
+
+Please read :ref:`Creating a plugin <pluginsetup>` first, if you haven't already.
+
+Output registration
+-------------------
+
+The invoice renderer API does not make a lot of usage from signals, however, it
+does use a signal to get a list of all available ticket outputs. Your plugin
+should listen for this signal and return the subclass of ``pretix.base.invoice.BaseInvoiceRenderer``
+that we'll provide in this plugin::
+
+    from django.dispatch import receiver
+
+    from pretix.base.signals import register_invoice_renderers
+
+
+    @receiver(register_invoice_renderers, dispatch_uid="output_custom")
+    def register_infoice_renderers(sender, **kwargs):
+        from .invoice import MyInvoiceRenderer
+        return MyInvoiceRenderer
+
+
+The renderer class
+------------------
+
+.. class:: pretix.base.invoice.BaseInvoiceRenderer
+
+   The central object of each invoice renderer is the subclass of ``BaseInvoiceRenderer``.
+
+   .. py:attribute:: BaseInvoiceRenderer.event
+
+      The default constructor sets this property to the event we are currently
+      working for.
+
+   .. autoattribute:: identifier
+
+      This is an abstract attribute, you **must** override this!
+
+   .. autoattribute:: verbose_name
+
+      This is an abstract attribute, you **must** override this!
+
+   .. automethod:: generate
+
+Helper class for reportlab-base renderers
+-----------------------------------------
+
+All PDF rendering that ships with pretix is based on reportlab. We recommend to read the
+`reportlab User Guide`_ to understand all the concepts used here.
+
+If you want to implement a renderer that also uses report lab, this helper class might be
+convenient to you:
+
+
+.. class:: pretix.base.invoice.BaseReportlabInvoiceRenderer
+
+   .. py:attribute:: BaseReportlabInvoiceRenderer.pagesize
+
+   .. py:attribute:: BaseReportlabInvoiceRenderer.left_margin
+
+   .. py:attribute:: BaseReportlabInvoiceRenderer.right_margin
+
+   .. py:attribute:: BaseReportlabInvoiceRenderer.top_margin
+
+   .. py:attribute:: BaseReportlabInvoiceRenderer.bottom_margin
+
+   .. py:attribute:: BaseReportlabInvoiceRenderer.doc_template_class
+
+   .. py:attribute:: BaseReportlabInvoiceRenderer.invoice
+
+   .. automethod:: _init
+
+   .. automethod:: _get_stylesheet
+
+   .. automethod:: _register_fonts
+
+   .. automethod:: _on_first_page
+
+   .. automethod:: _on_other_page
+
+   .. automethod:: _get_first_page_frames
+
+   .. automethod:: _get_other_page_frames
+
+   .. automethod:: _build_doc
+
+.. _reportlab User Guide: https://www.reportlab.com/docs/reportlab-userguide.pdf

src/pretix/base/__init__.py

@@ -9,6 +9,7 @@ class PretixBaseConfig(AppConfig):
         from . import exporter  # NOQA
         from . import payment  # NOQA
         from . import exporters  # NOQA
+        from . import invoice  # NOQA
         from .services import export, mail, tickets, cart, orders, cleanup, update_check  # NOQA
 
         try:

src/pretix/base/invoice.py

@@ -0,0 +1,411 @@
+from collections import defaultdict
+from decimal import Decimal
+from io import BytesIO
+from typing import Tuple
+
+from django.contrib.staticfiles import finders
+from django.dispatch import receiver
+from django.utils.formats import date_format, localize
+from django.utils.translation import pgettext
+from reportlab.lib import pagesizes
+from reportlab.lib.styles import ParagraphStyle, StyleSheet1
+from reportlab.lib.units import mm
+from reportlab.lib.utils import ImageReader
+from reportlab.pdfbase import pdfmetrics
+from reportlab.pdfbase.ttfonts import TTFont
+from reportlab.pdfgen.canvas import Canvas
+from reportlab.platypus import (
+    BaseDocTemplate, Frame, NextPageTemplate, PageTemplate, Paragraph, Spacer,
+    Table, TableStyle,
+)
+
+from pretix.base.models import Event, Invoice
+from pretix.base.signals import register_invoice_renderers
+
+
+class BaseInvoiceRenderer:
+    """
+    This is the base class for all invoice renderers.
+    """
+
+    def __init__(self, event: Event):
+        self.event = event
+
+    def __str__(self):
+        return self.identifier
+
+    def generate(self, invoice: Invoice) -> Tuple[str, str, str]:
+        """
+        This method should generate the invoice file and return a tuple consisting of a
+        filename, a file type and file content. The extension will be taken from the filename
+        which is otherwise ignored.
+        """
+        raise NotImplementedError()
+
+    @property
+    def verbose_name(self) -> str:
+        """
+        A human-readable name for this renderer. This should be short but
+        self-explanatory. Good examples include 'German DIN 5008' or 'Italian invoice'.
+        """
+        raise NotImplementedError()  # NOQA
+
+    @property
+    def identifier(self) -> str:
+        """
+        A short and unique identifier for this renderer.
+        This should only contain lowercase letters and in most
+        cases will be the same as your package name.
+        """
+        raise NotImplementedError()  # NOQA
+
+
+class BaseReportlabInvoiceRenderer(BaseInvoiceRenderer):
+    """
+    This is a convenience class to avoid duplicate code when implementing invoice renderers
+    that are based on reportlab.
+    """
+    pagesize = pagesizes.A4
+    left_margin = 25 * mm
+    right_margin = 20 * mm
+    top_margin = 20 * mm
+    bottom_margin = 15 * mm
+    doc_template_class = BaseDocTemplate
+
+    def _init(self):
+        """
+        Initialize the renderer. By default, this registers fonts and sets ``self.stylesheet``.
+        """
+        self.stylesheet = self._get_stylesheet()
+        self._register_fonts()
+
+    def _get_stylesheet(self):
+        """
+        Get a stylesheet. By default, this contains the "Normal" and "Heading1" styles.
+        """
+        stylesheet = StyleSheet1()
+        stylesheet.add(ParagraphStyle(name='Normal', fontName='OpenSans', fontSize=10, leading=12))
+        stylesheet.add(ParagraphStyle(name='Heading1', fontName='OpenSansBd', fontSize=15, leading=15 * 1.2))
+        return stylesheet
+
+    def _register_fonts(self):
+        """
+        Register fonts with reportlab. By default, this registers the OpenSans font family
+        """
+        pdfmetrics.registerFont(TTFont('OpenSans', finders.find('fonts/OpenSans-Regular.ttf')))
+        pdfmetrics.registerFont(TTFont('OpenSansIt', finders.find('fonts/OpenSans-Italic.ttf')))
+        pdfmetrics.registerFont(TTFont('OpenSansBd', finders.find('fonts/OpenSans-Bold.ttf')))
+        pdfmetrics.registerFont(TTFont('OpenSansBI', finders.find('fonts/OpenSans-BoldItalic.ttf')))
+        pdfmetrics.registerFontFamily('OpenSans', normal='OpenSans', bold='OpenSansBd',
+                                      italic='OpenSansIt', boldItalic='OpenSansBI')
+
+    def _on_other_page(self, canvas: Canvas, doc):
+        """
+        Called when a new page is rendered that is *not* the first page.
+        """
+        pass
+
+    def _on_first_page(self, canvas: Canvas, doc):
+        """
+        Called when a new page is rendered that is the first page.
+        """
+        pass
+
+    def _get_story(self, doc):
+        """
+        Called to create the story to be inserted into the main frames.
+        """
+        raise NotImplementedError()
+
+    def _get_first_page_frames(self, doc):
+        """
+        Called to create a list of frames for the first page.
+        """
+        return [
+            Frame(doc.leftMargin, doc.bottomMargin, doc.width, doc.height - 75 * mm,
+                  leftPadding=0, rightPadding=0, topPadding=0, bottomPadding=0,
+                  id='normal')
+        ]
+
+    def _get_other_page_frames(self, doc):
+        """
+        Called to create a list of frames for the other pages.
+        """
+        return [
+            Frame(doc.leftMargin, doc.bottomMargin, doc.width, doc.height,
+                  leftPadding=0, rightPadding=0, topPadding=0, bottomPadding=0,
+                  id='normal')
+        ]
+
+    def _build_doc(self, fhandle):
+        """
+        Build a PDF document in a given file handle
+        """
+        self._init()
+        doc = self.doc_template_class(fhandle, pagesize=self.pagesize,
+                                      leftMargin=self.left_margin, rightMargin=self.right_margin,
+                                      topMargin=self.top_margin, bottomMargin=self.bottom_margin)
+
+        doc.addPageTemplates([
+            PageTemplate(
+                id='FirstPage',
+                frames=self._get_first_page_frames(doc),
+                onPage=self._on_first_page,
+                pagesize=self.pagesize
+            ),
+            PageTemplate(
+                id='OtherPages',
+                frames=self._get_other_page_frames(doc),
+                onPage=self._on_other_page,
+                pagesize=self.pagesize
+            )
+        ])
+        story = self._get_story(doc)
+        doc.build(story)
+        return doc
+
+    def generate(self, invoice: Invoice):
+        self.invoice = invoice
+        buffer = BytesIO()
+        self._build_doc(buffer)
+        buffer.seek(0)
+        return 'invoice.pdf', 'application/pdf', buffer.read()
+
+
+class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
+    identifier = 'classic'
+    verbose_name = pgettext('invoice', 'Classic renderer (pretix 1.0)')
+
+    def _on_other_page(self, canvas: Canvas, doc):
+        canvas.saveState()
+        canvas.setFont('OpenSans', 8)
+        canvas.drawRightString(self.pagesize[0] - 20 * mm, 10 * mm, pgettext("invoice", "Page %d") % (doc.page,))
+
+        for i, line in enumerate(self.invoice.footer_text.split('\n')[::-1]):
+            canvas.drawCentredString(self.pagesize[0] / 2, 25 + (3.5 * i) * mm, line.strip())
+
+        canvas.restoreState()
+
+    def _on_first_page(self, canvas: Canvas, doc):
+        canvas.setCreator('pretix.eu')
+        canvas.setTitle(pgettext('invoice', 'Invoice {num}').format(num=self.invoice.number))
+
+        canvas.saveState()
+        canvas.setFont('OpenSans', 8)
+        canvas.drawRightString(self.pagesize[0] - 20 * mm, 10 * mm, pgettext("invoice", "Page %d") % (doc.page,))
+
+        for i, line in enumerate(self.invoice.footer_text.split('\n')[::-1]):
+            canvas.drawCentredString(self.pagesize[0] / 2, 25 + (3.5 * i) * mm, line.strip())
+
+        textobject = canvas.beginText(25 * mm, (297 - 15) * mm)
+        textobject.setFont('OpenSansBd', 8)
+        textobject.textLine(pgettext('invoice', 'Invoice from').upper())
+        canvas.drawText(textobject)
+
+        p = Paragraph(self.invoice.invoice_from.strip().replace('\n', '<br />\n'), style=self.stylesheet['Normal'])
+        p.wrapOn(canvas, 70 * mm, 50 * mm)
+        p_size = p.wrap(70 * mm, 50 * mm)
+        p.drawOn(canvas, 25 * mm, (297 - 17) * mm - p_size[1])
+
+        textobject = canvas.beginText(25 * mm, (297 - 50) * mm)
+        textobject.setFont('OpenSansBd', 8)
+        textobject.textLine(pgettext('invoice', 'Invoice to').upper())
+        canvas.drawText(textobject)
+
+        p = Paragraph(self.invoice.invoice_to.strip().replace('\n', '<br />\n'), style=self.stylesheet['Normal'])
+        p.wrapOn(canvas, 85 * mm, 50 * mm)
+        p_size = p.wrap(85 * mm, 50 * mm)
+        p.drawOn(canvas, 25 * mm, (297 - 52) * mm - p_size[1])
+
+        textobject = canvas.beginText(125 * mm, (297 - 38) * mm)
+        textobject.setFont('OpenSansBd', 8)
+        textobject.textLine(pgettext('invoice', 'Order code').upper())
+        textobject.moveCursor(0, 5)
+        textobject.setFont('OpenSans', 10)
+        textobject.textLine(self.invoice.order.full_code)
+        canvas.drawText(textobject)
+
+        textobject = canvas.beginText(125 * mm, (297 - 50) * mm)
+        textobject.setFont('OpenSansBd', 8)
+        if self.invoice.is_cancellation:
+            textobject.textLine(pgettext('invoice', 'Cancellation number').upper())
+            textobject.moveCursor(0, 5)
+            textobject.setFont('OpenSans', 10)
+            textobject.textLine(self.invoice.number)
+            textobject.moveCursor(0, 5)
+            textobject.setFont('OpenSansBd', 8)
+            textobject.textLine(pgettext('invoice', 'Original invoice').upper())
+            textobject.moveCursor(0, 5)
+            textobject.setFont('OpenSans', 10)
+            textobject.textLine(self.invoice.refers.number)
+        else:
+            textobject.textLine(pgettext('invoice', 'Invoice number').upper())
+            textobject.moveCursor(0, 5)
+            textobject.setFont('OpenSans', 10)
+            textobject.textLine(self.invoice.number)
+        textobject.moveCursor(0, 5)
+
+        if self.invoice.is_cancellation:
+            textobject.setFont('OpenSansBd', 8)
+            textobject.textLine(pgettext('invoice', 'Cancellation date').upper())
+            textobject.moveCursor(0, 5)
+            textobject.setFont('OpenSans', 10)
+            textobject.textLine(date_format(self.invoice.date, "DATE_FORMAT"))
+            textobject.moveCursor(0, 5)
+            textobject.setFont('OpenSansBd', 8)
+            textobject.textLine(pgettext('invoice', 'Original invoice date').upper())
+            textobject.moveCursor(0, 5)
+            textobject.setFont('OpenSans', 10)
+            textobject.textLine(date_format(self.invoice.refers.date, "DATE_FORMAT"))
+            textobject.moveCursor(0, 5)
+        else:
+            textobject.setFont('OpenSansBd', 8)
+            textobject.textLine(pgettext('invoice', 'Invoice date').upper())
+            textobject.moveCursor(0, 5)
+            textobject.setFont('OpenSans', 10)
+            textobject.textLine(date_format(self.invoice.date, "DATE_FORMAT"))
+            textobject.moveCursor(0, 5)
+
+        canvas.drawText(textobject)
+
+        if self.invoice.event.settings.invoice_logo_image:
+            logo_file = self.invoice.event.settings.get('invoice_logo_image', binary_file=True)
+            canvas.drawImage(ImageReader(logo_file),
+                             95 * mm, (297 - 38) * mm,
+                             width=25 * mm, height=25 * mm,
+                             preserveAspectRatio=True, anchor='n',
+                             mask='auto')
+
+        if self.invoice.event.settings.show_date_to:
+            p_str = (
+                str(self.invoice.event.name) + '\n' + pgettext('invoice', '{from_date}\nuntil {to_date}').format(
+                    from_date=self.invoice.event.get_date_from_display(),
+                    to_date=self.invoice.event.get_date_to_display())
+            )
+        else:
+            p_str = (
+                str(self.invoice.event.name) + '\n' + self.invoice.event.get_date_from_display()
+            )
+
+        p = Paragraph(p_str.strip().replace('\n', '<br />\n'), style=self.stylesheet['Normal'])
+        p.wrapOn(canvas, 65 * mm, 50 * mm)
+        p_size = p.wrap(65 * mm, 50 * mm)
+        p.drawOn(canvas, 125 * mm, (297 - 17) * mm - p_size[1])
+
+        textobject = canvas.beginText(125 * mm, (297 - 15) * mm)
+        textobject.setFont('OpenSansBd', 8)
+        textobject.textLine(pgettext('invoice', 'Event').upper())
+        canvas.drawText(textobject)
+
+        canvas.restoreState()
+
+    def _get_first_page_frames(self, doc):
+        footer_length = 3.5 * len(self.invoice.footer_text.split('\n')) * mm
+        return [
+            Frame(doc.leftMargin, doc.bottomMargin, doc.width, doc.height - 75 * mm,
+                  leftPadding=0, rightPadding=0, topPadding=0, bottomPadding=footer_length,
+                  id='normal')
+        ]
+
+    def _get_other_page_frames(self, doc):
+        footer_length = 3.5 * len(self.invoice.footer_text.split('\n')) * mm
+        return [
+            Frame(doc.leftMargin, doc.bottomMargin, doc.width, doc.height,
+                  leftPadding=0, rightPadding=0, topPadding=0, bottomPadding=footer_length,
+                  id='normal')
+        ]
+
+    def _get_story(self, doc):
+        story = [
+            NextPageTemplate('FirstPage'),
+            Paragraph(pgettext('invoice', 'Invoice')
+                      if not self.invoice.is_cancellation
+                      else pgettext('invoice', 'Cancellation'),
+                      self.stylesheet['Heading1']),
+            Spacer(1, 5 * mm),
+            NextPageTemplate('OtherPages'),
+        ]
+
+        if self.invoice.introductory_text:
+            story.append(Paragraph(self.invoice.introductory_text, self.stylesheet['Normal']))
+            story.append(Spacer(1, 10 * mm))
+
+        taxvalue_map = defaultdict(Decimal)
+        grossvalue_map = defaultdict(Decimal)
+
+        tstyledata = [
+            ('ALIGN', (1, 0), (-1, -1), 'RIGHT'),
+            ('VALIGN', (0, 0), (-1, -1), 'TOP'),
+            ('FONTNAME', (0, 0), (-1, 0), 'OpenSansBd'),
+            ('FONTNAME', (0, -1), (-1, -1), 'OpenSansBd'),
+            ('LEFTPADDING', (0, 0), (0, -1), 0),
+            ('RIGHTPADDING', (-1, 0), (-1, -1), 0),
+        ]
+        tdata = [(
+            pgettext('invoice', 'Description'),
+            pgettext('invoice', 'Tax rate'),
+            pgettext('invoice', 'Net'),
+            pgettext('invoice', 'Gross'),
+        )]
+        total = Decimal('0.00')
+        for line in self.invoice.lines.all():
+            tdata.append((
+                Paragraph(line.description, self.stylesheet['Normal']),
+                localize(line.tax_rate) + " %",
+                localize(line.net_value) + " " + self.invoice.event.currency,
+                localize(line.gross_value) + " " + self.invoice.event.currency,
+            ))
+            taxvalue_map[line.tax_rate] += line.tax_value
+            grossvalue_map[line.tax_rate] += line.gross_value
+            total += line.gross_value
+
+        tdata.append(
+            [pgettext('invoice', 'Invoice total'), '', '', localize(total) + " " + self.invoice.event.currency])
+        colwidths = [a * doc.width for a in (.55, .15, .15, .15)]
+        table = Table(tdata, colWidths=colwidths, repeatRows=1)
+        table.setStyle(TableStyle(tstyledata))
+        story.append(table)
+
+        story.append(Spacer(1, 15 * mm))
+
+        if self.invoice.payment_provider_text:
+            story.append(Paragraph(self.invoice.payment_provider_text, self.stylesheet['Normal']))
+
+        if self.invoice.additional_text:
+            story.append(Paragraph(self.invoice.additional_text, self.stylesheet['Normal']))
+            story.append(Spacer(1, 15 * mm))
+
+        tstyledata = [
+            ('SPAN', (1, 0), (-1, 0)),
+            ('ALIGN', (2, 1), (-1, -1), 'RIGHT'),
+            ('LEFTPADDING', (0, 0), (0, -1), 0),
+            ('RIGHTPADDING', (-1, 0), (-1, -1), 0),
+            ('FONTSIZE', (0, 0), (-1, -1), 8),
+        ]
+        tdata = [('', pgettext('invoice', 'Included taxes'), '', '', ''),
+                 ('', pgettext('invoice', 'Tax rate'),
+                  pgettext('invoice', 'Net value'), pgettext('invoice', 'Gross value'), pgettext('invoice', 'Tax'))]
+
+        for rate, gross in grossvalue_map.items():
+            if line.tax_rate == 0:
+                continue
+            tax = taxvalue_map[rate]
+            tdata.append((
+                '',
+                localize(rate) + " %",
+                localize((gross - tax)) + " " + self.invoice.event.currency,
+                localize(gross) + " " + self.invoice.event.currency,
+                localize(tax) + " " + self.invoice.event.currency,
+            ))
+
+        if len(tdata) > 2:
+            colwidths = [a * doc.width for a in (.45, .10, .15, .15, .15)]
+            table = Table(tdata, colWidths=colwidths, repeatRows=2)
+            table.setStyle(TableStyle(tstyledata))
+            story.append(table)
+        return story
+
+
+@receiver(register_invoice_renderers, dispatch_uid="invoice_renderer_classic")
+def recv_classic(sender, **kwargs):
+    return ClassicInvoiceRenderer

src/pretix/base/models/event.py

@@ -326,6 +326,24 @@ class Event(LoggedModel):
                 providers[pp.identifier] = pp
         return providers
 
+    def get_invoice_renderers(self) -> dict:
+        from ..signals import register_invoice_renderers
+
+        responses = register_invoice_renderers.send(self)
+        renderers = {}
+        for receiver, response in responses:
+            if not isinstance(response, list):
+                response = [response]
+            for p in response:
+                pp = p(self)
+                renderers[pp.identifier] = pp
+        return renderers
+
+    @property
+    def invoice_renderer(self):
+        irs = self.get_invoice_renderers()
+        return irs[self.settings.invoice_renderer]
+
 
 def generate_invite_token():
     return get_random_string(length=32, allowed_chars=string.ascii_lowercase + string.digits)

src/pretix/base/models/invoices.py

@@ -9,9 +9,10 @@ from django.utils.functional import cached_property
 
 def invoice_filename(instance, filename: str) -> str:
     secret = get_random_string(length=16, allowed_chars=string.ascii_letters + string.digits)
-    return 'invoices/{org}/{ev}/{no}-{code}-{secret}.pdf'.format(
+    return 'invoices/{org}/{ev}/{no}-{code}-{secret}.{ext}'.format(
         org=instance.event.organizer.slug, ev=instance.event.slug,
-        no=instance.number, code=instance.order.code, secret=secret
+        no=instance.number, code=instance.order.code, secret=secret,
+        ext=filename.split('.')[-1]
     )
 
 

src/pretix/base/services/invoices.py

@@ -1,25 +1,11 @@
 import copy
-import tempfile
-from collections import defaultdict
 from decimal import Decimal
 
-from django.contrib.staticfiles import finders
 from django.core.files.base import ContentFile
 from django.db import transaction
 from django.utils import timezone
-from django.utils.formats import date_format, localize
 from django.utils.translation import pgettext, ugettext as _
 from i18nfield.strings import LazyI18nString
-from reportlab.lib import pagesizes
-from reportlab.lib.styles import ParagraphStyle, StyleSheet1
-from reportlab.lib.units import mm
-from reportlab.lib.utils import ImageReader
-from reportlab.pdfbase import pdfmetrics
-from reportlab.pdfbase.ttfonts import TTFont
-from reportlab.platypus import (
-    BaseDocTemplate, Frame, NextPageTemplate, PageTemplate, Paragraph, Spacer,
-    Table, TableStyle,
-)
 
 from pretix.base.i18n import language
 from pretix.base.models import Invoice, InvoiceAddress, InvoiceLine, Order
@@ -77,7 +63,8 @@ def build_invoice(invoice: Invoice) -> Invoice:
 
         if invoice.order.payment_fee:
             InvoiceLine.objects.create(
-                invoice=invoice, description=_('Payment via {method}').format(method=str(payment_provider.verbose_name)),
+                invoice=invoice,
+                description=_('Payment via {method}').format(method=str(payment_provider.verbose_name)),
                 gross_value=invoice.order.payment_fee, tax_value=invoice.order.payment_fee_tax_value,
                 tax_rate=invoice.order.payment_fee_tax_rate
             )
@@ -138,265 +125,12 @@ def generate_invoice(order: Order):
     return invoice
 
 
-def _invoice_get_stylesheet():
-    stylesheet = StyleSheet1()
-    stylesheet.add(ParagraphStyle(name='Normal', fontName='OpenSans', fontSize=10, leading=12))
-    stylesheet.add(ParagraphStyle(name='Heading1', fontName='OpenSansBd', fontSize=15, leading=15 * 1.2))
-    return stylesheet
-
-
-def _invoice_register_fonts():
-    pdfmetrics.registerFont(TTFont('OpenSans', finders.find('fonts/OpenSans-Regular.ttf')))
-    pdfmetrics.registerFont(TTFont('OpenSansIt', finders.find('fonts/OpenSans-Italic.ttf')))
-    pdfmetrics.registerFont(TTFont('OpenSansBd', finders.find('fonts/OpenSans-Bold.ttf')))
-
-
-def _invoice_generate_german(invoice, f):
-    _invoice_register_fonts()
-    styles = _invoice_get_stylesheet()
-    pagesize = pagesizes.A4
-
-    def on_page(canvas, doc):
-        canvas.saveState()
-        canvas.setFont('OpenSans', 8)
-        canvas.drawRightString(pagesize[0] - 20 * mm, 10 * mm, _("Page %d") % (doc.page,))
-
-        for i, line in enumerate(invoice.footer_text.split('\n')[::-1]):
-            canvas.drawCentredString(pagesize[0] / 2, 25 + (3.5 * i) * mm, line.strip())
-
-        canvas.restoreState()
-
-    def on_first_page(canvas, doc):
-        canvas.setCreator('pretix.eu')
-        canvas.setTitle(pgettext('invoice', 'Invoice {num}').format(num=invoice.number))
-
-        canvas.saveState()
-        canvas.setFont('OpenSans', 8)
-        canvas.drawRightString(pagesize[0] - 20 * mm, 10 * mm, _("Page %d") % (doc.page,))
-
-        for i, line in enumerate(invoice.footer_text.split('\n')[::-1]):
-            canvas.drawCentredString(pagesize[0] / 2, 25 + (3.5 * i) * mm, line.strip())
-
-        textobject = canvas.beginText(25 * mm, (297 - 15) * mm)
-        textobject.setFont('OpenSansBd', 8)
-        textobject.textLine(pgettext('invoice', 'Invoice from').upper())
-        canvas.drawText(textobject)
-
-        p = Paragraph(invoice.invoice_from.strip().replace('\n', '<br />\n'), style=styles['Normal'])
-        p.wrapOn(canvas, 70 * mm, 50 * mm)
-        p_size = p.wrap(70 * mm, 50 * mm)
-        p.drawOn(canvas, 25 * mm, (297 - 17) * mm - p_size[1])
-
-        textobject = canvas.beginText(25 * mm, (297 - 50) * mm)
-        textobject.setFont('OpenSansBd', 8)
-        textobject.textLine(pgettext('invoice', 'Invoice to').upper())
-        canvas.drawText(textobject)
-
-        p = Paragraph(invoice.invoice_to.strip().replace('\n', '<br />\n'), style=styles['Normal'])
-        p.wrapOn(canvas, 85 * mm, 50 * mm)
-        p_size = p.wrap(85 * mm, 50 * mm)
-        p.drawOn(canvas, 25 * mm, (297 - 52) * mm - p_size[1])
-
-        textobject = canvas.beginText(125 * mm, (297 - 38) * mm)
-        textobject.setFont('OpenSansBd', 8)
-        textobject.textLine(_('Order code').upper())
-        textobject.moveCursor(0, 5)
-        textobject.setFont('OpenSans', 10)
-        textobject.textLine(invoice.order.full_code)
-        canvas.drawText(textobject)
-
-        textobject = canvas.beginText(125 * mm, (297 - 50) * mm)
-        textobject.setFont('OpenSansBd', 8)
-        if invoice.is_cancellation:
-            textobject.textLine(pgettext('invoice', 'Cancellation number').upper())
-            textobject.moveCursor(0, 5)
-            textobject.setFont('OpenSans', 10)
-            textobject.textLine(invoice.number)
-            textobject.moveCursor(0, 5)
-            textobject.setFont('OpenSansBd', 8)
-            textobject.textLine(pgettext('invoice', 'Original invoice').upper())
-            textobject.moveCursor(0, 5)
-            textobject.setFont('OpenSans', 10)
-            textobject.textLine(invoice.refers.number)
-        else:
-            textobject.textLine(pgettext('invoice', 'Invoice number').upper())
-            textobject.moveCursor(0, 5)
-            textobject.setFont('OpenSans', 10)
-            textobject.textLine(invoice.number)
-        textobject.moveCursor(0, 5)
-
-        if invoice.is_cancellation:
-            textobject.setFont('OpenSansBd', 8)
-            textobject.textLine(pgettext('invoice', 'Cancellation date').upper())
-            textobject.moveCursor(0, 5)
-            textobject.setFont('OpenSans', 10)
-            textobject.textLine(date_format(invoice.date, "DATE_FORMAT"))
-            textobject.moveCursor(0, 5)
-            textobject.setFont('OpenSansBd', 8)
-            textobject.textLine(pgettext('invoice', 'Original invoice date').upper())
-            textobject.moveCursor(0, 5)
-            textobject.setFont('OpenSans', 10)
-            textobject.textLine(date_format(invoice.refers.date, "DATE_FORMAT"))
-            textobject.moveCursor(0, 5)
-        else:
-            textobject.setFont('OpenSansBd', 8)
-            textobject.textLine(pgettext('invoice', 'Invoice date').upper())
-            textobject.moveCursor(0, 5)
-            textobject.setFont('OpenSans', 10)
-            textobject.textLine(date_format(invoice.date, "DATE_FORMAT"))
-            textobject.moveCursor(0, 5)
-
-        canvas.drawText(textobject)
-
-        if invoice.event.settings.invoice_logo_image:
-            logo_file = invoice.event.settings.get('invoice_logo_image', binary_file=True)
-            canvas.drawImage(ImageReader(logo_file),
-                             95 * mm, (297 - 38) * mm,
-                             width=25 * mm, height=25 * mm,
-                             preserveAspectRatio=True, anchor='n',
-                             mask='auto')
-
-        if invoice.event.settings.show_date_to:
-            p_str = (
-                str(invoice.event.name) + '\n' + _('{from_date}\nuntil {to_date}').format(
-                    from_date=invoice.event.get_date_from_display(),
-                    to_date=invoice.event.get_date_to_display())
-            )
-        else:
-            p_str = (
-                str(invoice.event.name) + '\n' + invoice.event.get_date_from_display()
-            )
-
-        p = Paragraph(p_str.strip().replace('\n', '<br />\n'), style=styles['Normal'])
-        p.wrapOn(canvas, 65 * mm, 50 * mm)
-        p_size = p.wrap(65 * mm, 50 * mm)
-        p.drawOn(canvas, 125 * mm, (297 - 17) * mm - p_size[1])
-
-        textobject = canvas.beginText(125 * mm, (297 - 15) * mm)
-        textobject.setFont('OpenSansBd', 8)
-        textobject.textLine(_('Event').upper())
-        canvas.drawText(textobject)
-
-        canvas.restoreState()
-
-    doc = BaseDocTemplate(f.name, pagesize=pagesizes.A4,
-                          leftMargin=25 * mm, rightMargin=20 * mm,
-                          topMargin=20 * mm, bottomMargin=15 * mm)
-
-    footer_length = 3.5 * len(invoice.footer_text.split('\n')) * mm
-    frames_p1 = [
-        Frame(doc.leftMargin, doc.bottomMargin, doc.width, doc.height - 75 * mm,
-              leftPadding=0, rightPadding=0, topPadding=0, bottomPadding=footer_length,
-              id='normal')
-    ]
-    frames = [
-        Frame(doc.leftMargin, doc.bottomMargin, doc.width, doc.height,
-              leftPadding=0, rightPadding=0, topPadding=0, bottomPadding=footer_length,
-              id='normal')
-    ]
-    doc.addPageTemplates([
-        PageTemplate(id='FirstPage', frames=frames_p1, onPage=on_first_page, pagesize=pagesize),
-        PageTemplate(id='OtherPages', frames=frames, onPage=on_page, pagesize=pagesize)
-    ])
-    story = [
-        NextPageTemplate('FirstPage'),
-        Paragraph(pgettext('invoice', 'Invoice')
-                  if not invoice.is_cancellation
-                  else pgettext('invoice', 'Cancellation'),
-                  styles['Heading1']),
-        Spacer(1, 5 * mm),
-        NextPageTemplate('OtherPages'),
-    ]
-
-    if invoice.introductory_text:
-        story.append(Paragraph(invoice.introductory_text, styles['Normal']))
-        story.append(Spacer(1, 10 * mm))
-
-    taxvalue_map = defaultdict(Decimal)
-    grossvalue_map = defaultdict(Decimal)
-
-    tstyledata = [
-        ('ALIGN', (1, 0), (-1, -1), 'RIGHT'),
-        ('VALIGN', (0, 0), (-1, -1), 'TOP'),
-        ('FONTNAME', (0, 0), (-1, 0), 'OpenSansBd'),
-        ('FONTNAME', (0, -1), (-1, -1), 'OpenSansBd'),
-        ('LEFTPADDING', (0, 0), (0, -1), 0),
-        ('RIGHTPADDING', (-1, 0), (-1, -1), 0),
-    ]
-    tdata = [(
-        pgettext('invoice', 'Description'),
-        pgettext('invoice', 'Tax rate'),
-        pgettext('invoice', 'Net'),
-        pgettext('invoice', 'Gross'),
-    )]
-    total = Decimal('0.00')
-    for line in invoice.lines.all():
-        tdata.append((
-            Paragraph(line.description, styles['Normal']),
-            localize(line.tax_rate) + " %",
-            localize(line.net_value) + " " + invoice.event.currency,
-            localize(line.gross_value) + " " + invoice.event.currency,
-        ))
-        taxvalue_map[line.tax_rate] += line.tax_value
-        grossvalue_map[line.tax_rate] += line.gross_value
-        total += line.gross_value
-
-    tdata.append([pgettext('invoice', 'Invoice total'), '', '', localize(total) + " " + invoice.event.currency])
-    colwidths = [a * doc.width for a in (.55, .15, .15, .15)]
-    table = Table(tdata, colWidths=colwidths, repeatRows=1)
-    table.setStyle(TableStyle(tstyledata))
-    story.append(table)
-
-    story.append(Spacer(1, 15 * mm))
-
-    if invoice.payment_provider_text:
-        story.append(Paragraph(invoice.payment_provider_text, styles['Normal']))
-
-    if invoice.additional_text:
-        story.append(Paragraph(invoice.additional_text, styles['Normal']))
-        story.append(Spacer(1, 15 * mm))
-
-    tstyledata = [
-        ('SPAN', (1, 0), (-1, 0)),
-        ('ALIGN', (2, 1), (-1, -1), 'RIGHT'),
-        ('LEFTPADDING', (0, 0), (0, -1), 0),
-        ('RIGHTPADDING', (-1, 0), (-1, -1), 0),
-        ('FONTSIZE', (0, 0), (-1, -1), 8),
-    ]
-    tdata = [('', pgettext('invoice', 'Included taxes'), '', '', ''),
-             ('', pgettext('invoice', 'Tax rate'),
-              pgettext('invoice', 'Net value'), pgettext('invoice', 'Gross value'), pgettext('invoice', 'Tax'))]
-
-    for rate, gross in grossvalue_map.items():
-        if line.tax_rate == 0:
-            continue
-        tax = taxvalue_map[rate]
-        tdata.append((
-            '',
-            localize(rate) + " %",
-            localize((gross - tax)) + " " + invoice.event.currency,
-            localize(gross) + " " + invoice.event.currency,
-            localize(tax) + " " + invoice.event.currency,
-        ))
-
-    if len(tdata) > 2:
-        colwidths = [a * doc.width for a in (.45, .10, .15, .15, .15)]
-        table = Table(tdata, colWidths=colwidths, repeatRows=2)
-        table.setStyle(TableStyle(tstyledata))
-        story.append(table)
-
-    doc.build(story)
-    return doc
-
-
 @app.task(base=TransactionAwareTask)
 def invoice_pdf_task(invoice: int):
     i = Invoice.objects.get(pk=invoice)
     with language(i.locale):
-        with tempfile.NamedTemporaryFile(suffix=".pdf") as f:
-            _invoice_generate_german(i, f)
-            f.seek(0)
-            i.file.save('invoice.pdf', ContentFile(f.read()))
+        fname, ftype, fcontent = i.event.invoice_renderer.generate(i)
+        i.file.save(fname, ContentFile(fcontent))
         i.save()
         return i.file.name
 
@@ -452,7 +186,4 @@ def build_preview_invoice_pdf(event):
             gross_value=119, tax_value=19,
             tax_rate=19
         )
-        with tempfile.NamedTemporaryFile(suffix=".pdf") as f:
-            _invoice_generate_german(invoice, f)
-            f.seek(0)
-            return f.read()
+        return event.invoice_renderer.generate(invoice)

src/pretix/base/settings.py

@@ -55,6 +55,10 @@ DEFAULTS = {
         'default': 'True',
         'type': bool,
     },
+    'invoice_renderer': {
+        'default': 'classic',
+        'type': str,
+    },
     'reservation_time': {
         'default': '30',
         'type': int

src/pretix/base/signals.py

@@ -82,6 +82,16 @@ subclass of pretix.base.payment.BasePaymentProvider
 As with all event-plugin signals, the ``sender`` keyword argument will contain the event.
 """
 
+register_invoice_renderers = EventPluginSignal(
+    providing_args=[]
+)
+"""
+This signal is sent out to get all known invoice renderers. Receivers should return a
+subclass of pretix.base.invoice.BaseInvoiceRenderer
+
+As with all event-plugin signals, the ``sender`` keyword argument will contain the event.
+"""
+
 register_ticket_outputs = EventPluginSignal(
     providing_args=[]
 )

src/pretix/control/forms/event.py

@@ -436,6 +436,11 @@ class InvoiceSettingsForm(SettingsForm):
             ('paid', _('Automatically on payment')),
         )
     )
+    invoice_renderer = forms.ChoiceField(
+        label=_("Invoice style"),
+        required=True,
+        choices=[]
+    )
     invoice_address_from = forms.CharField(
         widget=forms.Textarea(attrs={'rows': 5}), required=False,
         label=_("Your address"),
@@ -472,6 +477,13 @@ class InvoiceSettingsForm(SettingsForm):
         help_text=_('We will show your logo with a maximal height and width of 2.5 cm.')
     )
 
+    def __init__(self, *args, **kwargs):
+        event = kwargs.get('obj')
+        super().__init__(*args, **kwargs)
+        self.fields['invoice_renderer'].choices = [
+            (r.identifier, r.verbose_name) for r in event.get_invoice_renderers().values()
+        ]
+
 
 class MailSettingsForm(SettingsForm):
     mail_prefix = forms.CharField(

src/pretix/control/templates/pretixcontrol/event/invoicing.html

@@ -12,6 +12,7 @@
             {% bootstrap_field form.invoice_address_vatid layout="horizontal" %}
             {% bootstrap_field form.invoice_numbers_consecutive layout="horizontal" %}
             {% bootstrap_field form.invoice_generate layout="horizontal" %}
+            {% bootstrap_field form.invoice_renderer layout="horizontal" %}
             {% bootstrap_field form.invoice_language layout="horizontal" %}
             {% bootstrap_field form.invoice_address_from layout="horizontal" %}
             {% bootstrap_field form.invoice_introductory_text layout="horizontal" %}

src/pretix/control/views/event.py

@@ -310,9 +310,9 @@ class InvoicePreview(EventPermissionRequiredMixin, View):
     permission = 'can_change_event_settings'
 
     def get(self, request, *args, **kwargs):
-        pdf = build_preview_invoice_pdf(request.event)
-        resp = HttpResponse(pdf, content_type='application/pdf')
-        resp['Content-Disposition'] = 'attachment; filename="invoice-preview.pdf"'
+        fname, ftype, fcontent = build_preview_invoice_pdf(request.event)
+        resp = HttpResponse(fcontent, content_type=ftype)
+        resp['Content-Disposition'] = 'attachment; filename="{}"'.format(fname)
         return resp