Support custom fonts

src/pretix/presale/style.py

@@ -8,6 +8,7 @@ import sass
 from django.conf import settings
 from django.core.files.base import ContentFile
 from django.core.files.storage import default_storage
+from django.dispatch import Signal
 from django.templatetags.static import static as _static
 
 from pretix.base.models import Event
@@ -23,11 +24,6 @@ def regenerate_css(event_id: int):
     event = Event.objects.select_related('organizer').get(pk=event_id)
     sassdir = os.path.join(settings.STATIC_ROOT, 'pretixpresale/scss')
 
-    sassrules = []
-    if event.settings.get('primary_color'):
-        sassrules.append('$brand-primary: {};'.format(event.settings.get('primary_color')))
-    sassrules.append('@import "main.scss";')
-
     def static(path):
         sp = _static(path)
         if not settings.MEDIA_URL.startswith("/") and sp.startswith("/"):
@@ -41,6 +37,19 @@ def regenerate_css(event_id: int):
                 sp = urljoin(settings.SITE_URL, sp)
         return '"{}"'.format(sp)
 
+    sassrules = []
+    if event.settings.get('primary_color'):
+        sassrules.append('$brand-primary: {};'.format(event.settings.get('primary_color')))
+
+    font = event.settings.get('primary_font')
+    if font != 'Open Sans':
+        sassrules.append(get_font_stylesheet(font))
+        sassrules.append('$font-family-sans-serif: "{}", "Open Sans", "OpenSans", "Helvetica Neue", Helvetica, Arial, sans-serif !default'.format(
+            font
+        ))
+
+    sassrules.append('@import "main.scss";')
+
     cf = dict(django_libsass.CUSTOM_FUNCTIONS)
     cf['static'] = static
     css = sass.compile(
@@ -57,3 +66,62 @@ def regenerate_css(event_id: int):
         newname = default_storage.save(fname, ContentFile(css.encode('utf-8')))
         event.settings.set('presale_css_file', newname)
         event.settings.set('presale_css_checksum', checksum)
+
+
+register_fonts = Signal()
+"""
+Return a dictionaries of the following structure. Paths should be relative to static root.
+
+{
+    "font name": {
+        "regular": {
+            "truetype": "….ttf",
+            "woff": "…",
+            "woff2": "…"
+        },
+        "bold": {
+            ...
+        },
+        "italic": {
+            ...
+        },
+        "bolditalic": {
+            ...
+        }
+    }
+}
+"""
+
+
+def get_fonts():
+    f = {}
+    for recv, value in register_fonts.send(0):
+        f.update(value)
+    return f
+
+
+def get_font_stylesheet(font_name):
+    stylesheet = []
+    font = get_fonts()[font_name]
+    for sty, formats in font.items():
+        stylesheet.append('@font-face { ')
+        stylesheet.append('font-family: "{}";'.format(font_name))
+        if sty in ("italic", "bolditalic"):
+            stylesheet.append("font-style: italic;")
+        else:
+            stylesheet.append("font-style: normal;")
+        if sty in ("bold", "bolditalic"):
+            stylesheet.append("font-weight: bold;")
+        else:
+            stylesheet.append("font-weight: normal;")
+
+        srcs = []
+        if "woff2" in formats:
+            srcs.append("url(static('{}')) format('woff2')".format(formats['woff2']))
+        if "woff" in formats:
+            srcs.append("url(static('{}')) format('woff')".format(formats['woff']))
+        if "truetype" in formats:
+            srcs.append("url(static('{}')) format('truetype')".format(formats['truetype']))
+        stylesheet.append("src: {};".format(", ".join(srcs)))
+        stylesheet.append("}")
+    return "\n".join(stylesheet)