From f05881ece7d924202437aa5e85d551479f40af93 Mon Sep 17 00:00:00 2001
From: Adrian Cochrane <adrian@openwork.nz>
Date: Fri, 2 Dec 2022 14:12:15 +1300
Subject: [PATCH] Parse src property for @font-face into custom FontConfig
 property.

---
 Graphics/Text/Font/Choose/FontSet.hs | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/Graphics/Text/Font/Choose/FontSet.hs b/Graphics/Text/Font/Choose/FontSet.hs
index 85ca81c..9d2bad2 100644
--- a/Graphics/Text/Font/Choose/FontSet.hs
+++ b/Graphics/Text/Font/Choose/FontSet.hs
@@ -71,6 +71,26 @@ thawFontSet_ cb = bracket (throwNull <$> cb) fcFontSetDestroy thawFontSet
 
 data FontFaceParser a = FontFaceParser { cssFonts :: FontSet, cssInner :: a}
 
+parseFontFaceSrc (Function "local":Ident name:RightParen:Comma:rest) =
+    ("local:" ++ unpack name):parseFontFaceSrc rest
+parseFontFaceSrc (Function "local":String name:RightParen:Comma:rest) =
+    ("local:" ++ unpack name):parseFontFaceSrc rest
+parseFontFaceSrc (Function "local":Ident name:RightParen:[]) = ["local:" ++ unpack name]
+parseFontFaceSrc (Function "local":String name:RightParen:[]) = ["local:" ++ unpack name]
+
+parseFontFaceSrc (Url link:toks)
+    | Comma:rest <- skipMeta toks = unpack link:parseFontFaceSrc rest
+    | [] <- skipMeta toks = [unpack link]
+    | otherwise = [""] -- Error indicator!
+  where
+    skipMeta (Function "format":Ident _:RightParen:rest) = skipMeta rest
+    skipMeta (Function "format":String _:RightParen:rest) = skipMeta rest
+    skipMeta (Function "tech":Ident _:RightParen:rest) = skipMeta rest
+    skipMeta (Function "tech":String _:RightParen:rest) = skipMeta rest
+    skipMeta toks = toks
+
+parseFontFaceSrc _ = [""]
+
 properties2font :: [(Text, [Token])] -> Pattern
 properties2font (("font-family", [String font]):props) =
     setValue "family" Strong (unpack font) $ properties2font props
@@ -102,6 +122,11 @@ properties2font (("unicode-range", toks):props)
     | Just chars <- parseCharSet $ unpack $ serialize toks =
         setValue "charset" Strong chars $ properties2font props
 
+-- Ignoring metadata & trusting in FreeType's broad support for fonts.
+properties2font (("src", toks):props)
+    | fonts@(_:_) <- parseFontFaceSrc toks, "" `notElem` fonts =
+        setValue "web-src" Strong (intercalate "\t" fonts) $ properties2font props
+
 properties2font (_:props) = properties2font props
 properties2font [] = []
 
-- 
2.30.2