| //! 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? |
| /// |
| /// <https://gitlab.freedesktop.org/freetype/freetype/-/blob/80a507a6b8e3d2906ad2c8ba69329bd2fb2a85ef/src/truetype/ttobjs.c#L174> |
| 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. |
| /// |
| /// <https://gitlab.freedesktop.org/freetype/freetype/-/blob/80a507a6b8e3d2906ad2c8ba69329bd2fb2a85ef/src/truetype/ttobjs.c#L153> |
| 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) |
| } |
| |
| /// <https://gitlab.freedesktop.org/freetype/freetype/-/blob/80a507a6b8e3d2906ad2c8ba69329bd2fb2a85ef/src/truetype/ttobjs.c#L180> |
| #[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<Self> { |
| let data = font.table_data(tag)?; |
| Some(Self { |
| // Note: FreeType always just computes the checksum |
| // <https://gitlab.freedesktop.org/freetype/freetype/-/blob/80a507a6b8e3d2906ad2c8ba69329bd2fb2a85ef/src/truetype/ttobjs.c#L281> |
| 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 <https://gitlab.freedesktop.org/freetype/freetype/-/blob/80a507a6b8e3d2906ad2c8ba69329bd2fb2a85ef/src/truetype/ttobjs.c#L309> |
| fn matches_hint_reliant_id_list(font_id: FontId) -> bool { |
| HINT_RELIANT_IDS.contains(&font_id) |
| } |
| |
| /// <https://gitlab.freedesktop.org/freetype/freetype/-/blob/80a507a6b8e3d2906ad2c8ba69329bd2fb2a85ef/src/truetype/ttobjs.c#L314> |
| #[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)); |
| } |
| } |
| } |
