//! Name detection for fonts that require hinting to be run for correct //! contours (FreeType calls these "tricky" fonts). use crate::{string::StringId, FontRef, MetadataProvider, Tag}; pub(super) fn require_interpreter(font: &FontRef) -> bool { is_hint_reliant_by_name(font) || matches_hint_reliant_id_list(FontId::from_font(font)) } fn is_hint_reliant_by_name(font: &FontRef) -> bool { font.localized_strings(StringId::FAMILY_NAME) .english_or_first() .map(|name| { let mut buf = [0u8; MAX_HINT_RELIANT_NAME_LEN]; let mut len = 0; let mut chars = name.chars(); for ch in chars.by_ref().take(MAX_HINT_RELIANT_NAME_LEN) { buf[len] = ch as u8; len += 1; } if chars.next().is_some() { return false; } matches_hint_reliant_name_list(core::str::from_utf8(&buf[..len]).unwrap_or_default()) }) .unwrap_or_default() } /// Is this name on the list of fonts that require hinting? /// /// fn matches_hint_reliant_name_list(name: &str) -> bool { let name = skip_pdf_random_tag(name); HINT_RELIANT_NAMES .iter() // FreeType uses strstr(name, tricky_name) so we use contains() to // match behavior. .any(|tricky_name| name.contains(*tricky_name)) } /// Fonts embedded in PDFs add random prefixes. Strip these /// for tricky font comparison purposes. /// /// fn skip_pdf_random_tag(name: &str) -> &str { let bytes = name.as_bytes(); // Random tag is 6 uppercase letters followed by a + if bytes.len() < 8 || bytes[6] != b'+' || !bytes.iter().take(6).all(|b| b.is_ascii_uppercase()) { return name; } core::str::from_utf8(&bytes[7..]).unwrap_or(name) } /// #[rustfmt::skip] const HINT_RELIANT_NAMES: &[&str] = &[ "cpop", /* dftt-p7.ttf; version 1.00, 1992 [DLJGyShoMedium] */ "DFGirl-W6-WIN-BF", /* dftt-h6.ttf; version 1.00, 1993 */ "DFGothic-EB", /* DynaLab Inc. 1992-1995 */ "DFGyoSho-Lt", /* DynaLab Inc. 1992-1995 */ "DFHei", /* DynaLab Inc. 1992-1995 [DFHei-Bd-WIN-HK-BF] */ /* covers "DFHei-Md-HK-BF", maybe DynaLab Inc. */ "DFHSGothic-W5", /* DynaLab Inc. 1992-1995 */ "DFHSMincho-W3", /* DynaLab Inc. 1992-1995 */ "DFHSMincho-W7", /* DynaLab Inc. 1992-1995 */ "DFKaiSho-SB", /* dfkaisb.ttf */ "DFKaiShu", /* covers "DFKaiShu-Md-HK-BF", maybe DynaLab Inc. */ "DFKai-SB", /* kaiu.ttf; version 3.00, 1998 [DFKaiShu-SB-Estd-BF] */ "DFMing", /* DynaLab Inc. 1992-1995 [DFMing-Md-WIN-HK-BF] */ /* covers "DFMing-Bd-HK-BF", maybe DynaLab Inc. */ "DLC", /* dftt-m7.ttf; version 1.00, 1993 [DLCMingBold] */ /* dftt-f5.ttf; version 1.00, 1993 [DLCFongSung] */ /* covers following */ /* "DLCHayMedium", dftt-b5.ttf; version 1.00, 1993 */ /* "DLCHayBold", dftt-b7.ttf; version 1.00, 1993 */ /* "DLCKaiMedium", dftt-k5.ttf; version 1.00, 1992 */ /* "DLCLiShu", dftt-l5.ttf; version 1.00, 1992 */ /* "DLCRoundBold", dftt-r7.ttf; version 1.00, 1993 */ "HuaTianKaiTi?", /* htkt2.ttf */ "HuaTianSongTi?", /* htst3.ttf */ "Ming(for ISO10646)", /* hkscsiic.ttf; version 0.12, 2007 [Ming] */ /* iicore.ttf; version 0.07, 2007 [Ming] */ "MingLiU", /* mingliu.ttf */ /* mingliu.ttc; version 3.21, 2001 */ "MingMedium", /* dftt-m5.ttf; version 1.00, 1993 [DLCMingMedium] */ "PMingLiU", /* mingliu.ttc; version 3.21, 2001 */ "MingLi43", /* mingli.ttf; version 1.00, 1992 */ ]; const MAX_HINT_RELIANT_NAME_LEN: usize = 18; #[derive(Copy, Clone, PartialEq, Default, Debug)] struct TableId { checksum: u32, len: u32, } impl TableId { fn from_font_and_tag(font: &FontRef, tag: Tag) -> Option { let data = font.table_data(tag)?; Some(Self { // Note: FreeType always just computes the checksum // checksum: raw::tables::compute_checksum(data.as_bytes()), len: data.len() as u32, }) } } #[derive(Copy, Clone, PartialEq, Default, Debug)] struct FontId { cvt: TableId, fpgm: TableId, prep: TableId, } impl FontId { fn from_font(font: &FontRef) -> Self { Self { cvt: TableId::from_font_and_tag(font, Tag::new(b"cvt ")).unwrap_or_default(), fpgm: TableId::from_font_and_tag(font, Tag::new(b"fpgm")).unwrap_or_default(), prep: TableId::from_font_and_tag(font, Tag::new(b"prep")).unwrap_or_default(), } } } /// Checks for fonts that require hinting based on the length and checksum of /// the cvt, fpgm and prep tables. /// /// Roughly equivalent to fn matches_hint_reliant_id_list(font_id: FontId) -> bool { HINT_RELIANT_IDS.contains(&font_id) } /// #[rustfmt::skip] const HINT_RELIANT_IDS: &[FontId] = &[ // MingLiU 1995 FontId { cvt: TableId { checksum: 0x05BCF058, len: 0x000002E4 }, fpgm: TableId { checksum: 0x28233BF1, len: 0x000087C4 }, prep: TableId { checksum: 0xA344A1EA, len: 0x000001E1 }, }, // MingLiU 1996- FontId { cvt: TableId { checksum: 0x05BCF058, len: 0x000002E4 }, fpgm: TableId { checksum: 0x28233BF1, len: 0x000087C4 }, prep: TableId { checksum: 0xA344A1EB, len: 0x000001E1 }, }, // DFGothic-EB FontId { cvt: TableId { checksum: 0x12C3EBB2, len: 0x00000350 }, fpgm: TableId { checksum: 0xB680EE64, len: 0x000087A7 }, prep: TableId { checksum: 0xCE939563, len: 0x00000758 }, }, // DFGyoSho-Lt FontId { cvt: TableId { checksum: 0x11E5EAD4, len: 0x00000350 }, fpgm: TableId { checksum: 0xCE5956E9, len: 0x0000BC85 }, prep: TableId { checksum: 0x8272F416, len: 0x00000045 }, }, // DFHei-Md-HK-BF FontId { cvt: TableId { checksum: 0x1257EB46, len: 0x00000350 }, fpgm: TableId { checksum: 0xF699D160, len: 0x0000715F }, prep: TableId { checksum: 0xD222F568, len: 0x000003BC }, }, // DFHSGothic-W5 FontId { cvt: TableId { checksum: 0x1262EB4E, len: 0x00000350 }, fpgm: TableId { checksum: 0xE86A5D64, len: 0x00007940 }, prep: TableId { checksum: 0x7850F729, len: 0x000005FF }, }, // DFHSMincho-W3 FontId { cvt: TableId { checksum: 0x122DEB0A, len: 0x00000350 }, fpgm: TableId { checksum: 0x3D16328A, len: 0x0000859B }, prep: TableId { checksum: 0xA93FC33B, len: 0x000002CB }, }, // DFHSMincho-W7 FontId { cvt: TableId { checksum: 0x125FEB26, len: 0x00000350 }, fpgm: TableId { checksum: 0xA5ACC982, len: 0x00007EE1 }, prep: TableId { checksum: 0x90999196, len: 0x0000041F }, }, // DFKaiShu FontId { cvt: TableId { checksum: 0x11E5EAD4, len: 0x00000350 }, fpgm: TableId { checksum: 0x5A30CA3B, len: 0x00009063 }, prep: TableId { checksum: 0x13A42602, len: 0x0000007E }, }, // DFKaiShu, variant FontId { cvt: TableId { checksum: 0x11E5EAD4, len: 0x00000350 }, fpgm: TableId { checksum: 0xA6E78C01, len: 0x00008998 }, prep: TableId { checksum: 0x13A42602, len: 0x0000007E }, }, // DFKaiShu-Md-HK-BF FontId { cvt: TableId { checksum: 0x11E5EAD4, len: 0x00000360 }, fpgm: TableId { checksum: 0x9DB282B2, len: 0x0000C06E }, prep: TableId { checksum: 0x53E6D7CA, len: 0x00000082 }, }, // DFMing-Bd-HK-BF FontId { cvt: TableId { checksum: 0x1243EB18, len: 0x00000350 }, fpgm: TableId { checksum: 0xBA0A8C30, len: 0x000074AD }, prep: TableId { checksum: 0xF3D83409, len: 0x0000037B }, }, // DLCLiShu FontId { cvt: TableId { checksum: 0x07DCF546, len: 0x00000308 }, fpgm: TableId { checksum: 0x40FE7C90, len: 0x00008E2A }, prep: TableId { checksum: 0x608174B5, len: 0x0000007A }, }, // DLCHayBold FontId { cvt: TableId { checksum: 0xEB891238, len: 0x00000308 }, fpgm: TableId { checksum: 0xD2E4DCD4, len: 0x0000676F }, prep: TableId { checksum: 0x8EA5F293, len: 0x000003B8 }, }, // HuaTianKaiTi FontId { cvt: TableId { checksum: 0xFFFBFFFC, len: 0x00000008 }, fpgm: TableId { checksum: 0x9C9E48B8, len: 0x0000BEA2 }, prep: TableId { checksum: 0x70020112, len: 0x00000008 }, }, // HuaTianSongTi FontId { cvt: TableId { checksum: 0xFFFBFFFC, len: 0x00000008 }, fpgm: TableId { checksum: 0x0A5A0483, len: 0x00017C39 }, prep: TableId { checksum: 0x70020112, len: 0x00000008 }, }, // NEC fadpop7.ttf FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x40C92555, len: 0x000000E5 }, prep: TableId { checksum: 0xA39B58E3, len: 0x0000117C }, }, // NEC fadrei5.ttf FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x33C41652, len: 0x000000E5 }, prep: TableId { checksum: 0x26D6C52A, len: 0x00000F6A }, }, // NEC fangot7.ttf FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x6DB1651D, len: 0x0000019D }, prep: TableId { checksum: 0x6C6E4B03, len: 0x00002492 }, }, // NEC fangyo5.ttf FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x40C92555, len: 0x000000E5 }, prep: TableId { checksum: 0xDE51FAD0, len: 0x0000117C }, }, // NEC fankyo5.ttf FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x85E47664, len: 0x000000E5 }, prep: TableId { checksum: 0xA6C62831, len: 0x00001CAA }, }, // NEC fanrgo5.ttf FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x2D891CFD, len: 0x0000019D }, prep: TableId { checksum: 0xA0604633, len: 0x00001DE8 }, }, // NEC fangot5.ttc FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x40AA774C, len: 0x000001CB }, prep: TableId { checksum: 0x9B5CAA96, len: 0x00001F9A }, }, // NEC fanmin3.ttc FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x0D3DE9CB, len: 0x00000141 }, prep: TableId { checksum: 0xD4127766, len: 0x00002280 }, }, // NEC FA-Gothic, 1996 FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x4A692698, len: 0x000001F0 }, prep: TableId { checksum: 0x340D4346, len: 0x00001FCA }, }, // NEC FA-Minchou, 1996 FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0xCD34C604, len: 0x00000166 }, prep: TableId { checksum: 0x6CF31046, len: 0x000022B0 }, }, // NEC FA-RoundGothicB, 1996 FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0x5DA75315, len: 0x0000019D }, prep: TableId { checksum: 0x40745A5F, len: 0x000022E0 }, }, // NEC FA-RoundGothicM, 1996 FontId { cvt: TableId { checksum: 0x00000000, len: 0x00000000 }, fpgm: TableId { checksum: 0xF055FC48, len: 0x000001C2 }, prep: TableId { checksum: 0x3900DED3, len: 0x00001E18 }, }, // MINGLI.TTF, 1992 FontId { cvt: TableId { checksum: 0x00170003, len: 0x00000060 }, fpgm: TableId { checksum: 0xDBB4306E, len: 0x000058AA }, prep: TableId { checksum: 0xD643482A, len: 0x00000035 }, }, // DFHei-Bd-WIN-HK-BF, issue #1087 FontId { cvt: TableId { checksum: 0x1269EB58, len: 0x00000350 }, fpgm: TableId { checksum: 0x5CD5957A, len: 0x00006A4E }, prep: TableId { checksum: 0xF758323A, len: 0x00000380 }, }, // DFMing-Md-WIN-HK-BF, issue #1087 FontId { cvt: TableId { checksum: 0x122FEB0B, len: 0x00000350 }, fpgm: TableId { checksum: 0x7F10919A, len: 0x000070A9 }, prep: TableId { checksum: 0x7CD7E7B7, len: 0x0000025C }, }, ]; #[cfg(test)] mod tests { use super::*; #[test] fn ensure_max_name_len() { let max_len = HINT_RELIANT_NAMES .iter() .fold(0, |acc, name| acc.max(name.len())); assert_eq!(max_len, MAX_HINT_RELIANT_NAME_LEN); } #[test] fn skip_pdf_tags() { // length must be at least 8 assert_eq!(skip_pdf_random_tag("ABCDEF+"), "ABCDEF+"); // first six chars must be ascii uppercase assert_eq!(skip_pdf_random_tag("AbCdEF+Arial"), "AbCdEF+Arial"); // no numbers assert_eq!(skip_pdf_random_tag("Ab12EF+Arial"), "Ab12EF+Arial"); // missing + assert_eq!(skip_pdf_random_tag("ABCDEFArial"), "ABCDEFArial"); // too long assert_eq!(skip_pdf_random_tag("ABCDEFG+Arial"), "ABCDEFG+Arial"); // too short assert_eq!(skip_pdf_random_tag("ABCDE+Arial"), "ABCDE+Arial"); // just right assert_eq!(skip_pdf_random_tag("ABCDEF+Arial"), "Arial"); } #[test] fn all_hint_reliant_names() { for name in HINT_RELIANT_NAMES { assert!(matches_hint_reliant_name_list(name)); } } #[test] fn non_hint_reliant_names() { for not_tricky in ["Roboto", "Arial", "Helvetica", "Blah", ""] { assert!(!matches_hint_reliant_name_list(not_tricky)); } } }