Skip to content

Commit

Permalink
(CFF) Added seac support.
Browse files Browse the repository at this point in the history
  • Loading branch information
@RazrFalcon
RazrFalcon committed Jul 16, 2020
1 parent ffc8d81 commit 5764253
Show file tree
Hide file tree
Showing 4 changed files with 250 additions and 10 deletions.
1 change: 1 addition & 0 deletions CHANGELOG.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
## [Unreleased]
### Added
- (CFF) CID fonts support.
- (CFF) `seac` support.
- `Font::global_bounding_box`

## [0.6.1] - 2020-07-02
Expand Down
2 changes: 0 additions & 2 deletions examples/font2svg.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -223,8 +223,6 @@ fn glyph_to_path(
svg: &mut xmlwriter::XmlWriter,
path_buf: &mut svgtypes::Path,
) {


path_buf.clear();
let mut builder = Builder(path_buf);
let bbox = match font.outline_glyph(glyph_id, &mut builder) {
Expand Down
7 changes: 7 additions & 0 deletions src/parser.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -142,6 +142,13 @@ pub trait TryNumFrom<T>: Sized {
fn try_num_from(_: T) -> Option<Self>;
}

impl TryNumFrom<f32> for u8 {
#[inline]
fn try_num_from(v: f32) -> Option<Self> {
i32::try_num_from(v).and_then(|v| u8::try_from(v).ok())
}
}

impl TryNumFrom<f32> for i16 {
#[inline]
fn try_num_from(v: f32) -> Option<Self> {
Expand Down
250 changes: 242 additions & 8 deletions src/tables/cff.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -72,7 +72,6 @@ mod private_dict_operator {

/// Enumerates Charset IDs defined in the Adobe Technical Note #5176, Table 22
mod charset_id {
#![allow(dead_code)]
pub const ISO_ADOBE: usize = 0;
pub const EXPERT: usize = 1;
pub const EXPERT_SUBSET: usize = 2;
Expand All @@ -98,6 +97,21 @@ pub enum CFFError {
InvalidNumberOfBlendOperands,
BlendRegionsLimitReached,
NoLocalSubroutines,
InvalidSeacCode,
}


/// A type-safe wrapper for string ID.
#[derive(Clone, Copy, PartialEq, PartialOrd, Debug)]
struct StringId(u16);

impl FromData for StringId {
const SIZE: usize = 2;

#[inline]
fn parse(data: &[u8]) -> Option<Self> {
u16::parse(data).map(StringId)
}
}


Expand All @@ -108,6 +122,7 @@ pub struct Metadata<'a> {
table_data: &'a [u8],

global_subrs: DataIndex<'a>,
charset: Charset<'a>,
char_strings: DataIndex<'a>,
kind: FontKind<'a>,
}
Expand Down Expand Up @@ -172,9 +187,18 @@ pub(crate) fn parse_metadata(data: &[u8]) -> Option<Metadata> {
return None;
}

// 'The number of glyphs is the value of the count field in the CharStrings INDEX.'
let number_of_glyphs = u16::try_from(char_strings.len()).ok()?;

let charset = match top_dict.charset_offset {
Some(charset_id::ISO_ADOBE) => Charset::ISOAdobe,
Some(charset_id::EXPERT) => Charset::Expert,
Some(charset_id::EXPERT_SUBSET) => Charset::ExpertSubset,
Some(offset) => parse_charset(number_of_glyphs, &mut Stream::new_at(data, offset)?)?,
None => Charset::ISOAdobe, // default
};

let kind = if top_dict.has_ros {
// 'The number of glyphs is the value of the count field in the CharStrings INDEX.'
let number_of_glyphs = u16::try_from(char_strings.len()).ok()?;
parse_cid_metadata(data, top_dict, number_of_glyphs)?
} else {
parse_sid_metadata(data, top_dict)?
Expand All @@ -183,6 +207,7 @@ pub(crate) fn parse_metadata(data: &[u8]) -> Option<Metadata> {
Some(Metadata {
table_data: data,
global_subrs,
charset,
char_strings,
kind,
})
Expand Down Expand Up @@ -351,6 +376,7 @@ struct CharStringParserContext<'a> {
width_parsed: bool,
stems_len: u32,
has_endchar: bool,
has_seac: bool,
glyph_id: GlyphId, // Required to parse local subroutine in CID fonts.
local_subrs: Option<DataIndex<'a>>,
}
Expand All @@ -373,6 +399,7 @@ fn parse_char_string(
width_parsed: false,
stems_len: 0,
has_endchar: false,
has_seac: false,
glyph_id,
local_subrs,
};
Expand Down Expand Up @@ -635,7 +662,7 @@ fn _parse_char_string(
return Err(CFFError::NoLocalSubroutines);
}

if ctx.has_endchar {
if ctx.has_endchar && !ctx.has_seac {
if !s.at_end() {
return Err(CFFError::DataAfterEndChar);
}
Expand Down Expand Up @@ -771,8 +798,33 @@ fn _parse_char_string(
}
}
operator::ENDCHAR => {
if !stack.is_empty() && !ctx.width_parsed {
stack.clear();
if stack.len() == 4 || (!ctx.width_parsed && stack.len() == 5) {
// Process 'seac'.
let accent_char = seac_code_to_glyph_id(&ctx.metadata.charset, stack.pop())
.ok_or(CFFError::InvalidSeacCode)?;
let base_char = seac_code_to_glyph_id(&ctx.metadata.charset, stack.pop())
.ok_or(CFFError::InvalidSeacCode)?;
let dy = stack.pop();
let dx = stack.pop();

if !ctx.width_parsed {
stack.pop();
ctx.width_parsed = true;
}

ctx.has_seac = true;

let base_char_string = ctx.metadata.char_strings.get(u32::from(base_char.0))
.ok_or(CFFError::InvalidSeacCode)?;
_parse_char_string(ctx, base_char_string, x, y, stack, depth + 1, builder)?;
x = dx;
y = dy;

let accent_char_string = ctx.metadata.char_strings.get(u32::from(accent_char.0))
.ok_or(CFFError::InvalidSeacCode)?;
_parse_char_string(ctx, accent_char_string, x, y, stack, depth + 1, builder)?;
} else if stack.len() == 1 && !ctx.width_parsed {
stack.pop();
ctx.width_parsed = true;
}

Expand Down Expand Up @@ -1009,7 +1061,7 @@ fn _parse_char_string(
x = pos.0;
y = pos.1;

if ctx.has_endchar {
if ctx.has_endchar && !ctx.has_seac {
if !s.at_end() {
return Err(CFFError::DataAfterEndChar);
}
Expand Down Expand Up @@ -1159,6 +1211,22 @@ pub fn calc_subroutine_bias(len: u32) -> u16 {
}
}

fn seac_code_to_glyph_id(charset: &Charset, n: f32) -> Option<GlyphId> {
let code = u8::try_num_from(n)?;

let sid = STANDARD_ENCODING[code as usize];
let sid = StringId(u16::from(sid));

match charset {
Charset::ISOAdobe => {
// Not sure why code should be less than 228/zcaron, but this is what harfbuzz does.
if code < 228 { Some(GlyphId(sid.0)) } else { None }
}
Charset::Expert | Charset::ExpertSubset => None,
_ => charset.sid_to_gid(sid),
}
}

fn parse_index<'a>(s: &mut Stream<'a>) -> Option<DataIndex<'a>> {
let count: u16 = s.read()?;
if count != 0 {
Expand Down Expand Up @@ -1565,10 +1633,153 @@ pub fn skip_number(b0: u8, s: &mut Stream) -> Option<()> {
}


#[derive(Clone, Copy, Debug)]
struct CharsetFormat1Range {
first: StringId,
left: u8,
}

impl FromData for CharsetFormat1Range {
const SIZE: usize = 3;

#[inline]
fn parse(data: &[u8]) -> Option<Self> {
let mut s = Stream::new(data);
Some(CharsetFormat1Range {
first: s.read()?,
left: s.read()?,
})
}
}


#[derive(Clone, Copy, Debug)]
struct CharsetFormat2Range {
first: StringId,
left: u16,
}

impl FromData for CharsetFormat2Range {
const SIZE: usize = 4;

#[inline]
fn parse(data: &[u8]) -> Option<Self> {
let mut s = Stream::new(data);
Some(CharsetFormat2Range {
first: s.read()?,
left: s.read()?,
})
}
}


#[derive(Clone, Copy, Debug)]
enum Charset<'a> {
ISOAdobe,
Expert,
ExpertSubset,
Format0(LazyArray16<'a, StringId>),
Format1(LazyArray16<'a, CharsetFormat1Range>),
Format2(LazyArray16<'a, CharsetFormat2Range>),
}

impl Charset<'_> {
fn sid_to_gid(&self, sid: StringId) -> Option<GlyphId> {
if sid.0 == 0 {
return Some(GlyphId(0));
}

match self {
Charset::ISOAdobe | Charset::Expert | Charset::ExpertSubset => None,
Charset::Format0(ref array) => {
// First glyph is omitted, so we have to add 1.
array.into_iter().position(|n| n == sid).map(|n| GlyphId(n as u16 + 1))
}
Charset::Format1(array) => {
let mut glyph_id = GlyphId(1);
for range in *array {
let last = u32::from(range.first.0) + u32::from(range.left);
if range.first <= sid && u32::from(sid.0) <= last {
glyph_id.0 += sid.0 - range.first.0;
return Some(glyph_id)
}

glyph_id.0 += u16::from(range.left) + 1;
}

None
}
Charset::Format2(array) => {
// The same as format 1, but Range::left is u16.
let mut glyph_id = GlyphId(1);
for range in *array {
let last = u32::from(range.first.0) + u32::from(range.left);
if sid >= range.first && u32::from(sid.0) <= last {
glyph_id.0 += sid.0 - range.first.0;
return Some(glyph_id)
}

glyph_id.0 += range.left + 1;
}

None
}
}
}
}

fn parse_charset<'a>(number_of_glyphs: u16, s: &mut Stream<'a>) -> Option<Charset<'a>> {
if number_of_glyphs < 2 {
return None;
}

// -1 everywhere, since `.notdef` is omitted.
let format: u8 = s.read()?;
match format {
0 => Some(Charset::Format0(s.read_array16(number_of_glyphs - 1)?)),
1 => {
// The number of ranges is not defined, so we have to
// read until no glyphs are left.
let mut count = 0;
{
let mut s = s.clone();
let mut total_left = number_of_glyphs - 1;
while total_left > 0 {
s.skip::<StringId>(); // first
let left: u8 = s.read()?;
total_left = total_left.checked_sub(u16::from(left) + 1)?;
count += 1;
}
}

s.read_array16(count).map(Charset::Format1)
}
2 => {
// The same as format 1, but Range::left is u16.
let mut count = 0;
{
let mut s = s.clone();
let mut total_left = number_of_glyphs - 1;
while total_left > 0 {
s.skip::<StringId>(); // first
let left: u16 = s.read()?;
let left = left.checked_add(1)?;
total_left = total_left.checked_sub(left)?;
count += 1;
}
}

s.read_array16(count).map(Charset::Format2)
}
_ => None,
}
}


#[derive(Clone, Copy, Debug)]
enum FDSelect<'a> {
Format0(LazyArray16<'a, u8>),
Format3(&'a [u8]), // It's easier to parse it inplace.
Format3(&'a [u8]), // It's easier to parse it in-place.
}

impl Default for FDSelect<'_> {
Expand Down Expand Up @@ -1712,6 +1923,26 @@ pub fn f32_abs(n: f32) -> f32 {
if n.is_sign_negative() { -n } else { n }
}

/// The Standard Encoding as defined in the Adobe Technical Note #5176 Appendix B.
const STANDARD_ENCODING: [u8;256] = [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64,
65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110,
0, 111, 112, 113, 114, 0, 115, 116, 117, 118, 119, 120, 121, 122, 0, 123,
0, 124, 125, 126, 127, 128, 129, 130, 131, 0, 132, 133, 0, 134, 135, 136,
137, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 138, 0, 139, 0, 0, 0, 0, 140, 141, 142, 143, 0, 0, 0, 0,
0, 144, 0, 0, 0, 145, 0, 0, 146, 147, 148, 149, 0, 0, 0, 0,
];


#[cfg(test)]
mod tests {
Expand Down Expand Up @@ -1796,6 +2027,9 @@ mod tests {
CFFError::NoLocalSubroutines => {
write!(f, "no local subroutines")
}
CFFError::InvalidSeacCode => {
write!(f, "invalid seac code")
}
}
}
}
Expand Down

0 comments on commit 5764253

Please sign in to comment.