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#![allow(trivial_numeric_casts)]
//! Embedding fonts in 2D for Pdf
use crate::{Error, PdfPage};
use lopdf;
use lopdf::StringFormat;
use lopdf::{Dictionary as LoDictionary, Stream as LoStream};
use owned_ttf_parser::{AsFaceRef as _, Face, OwnedFace};
use std::cell::RefCell;
use std::collections::{BTreeMap, HashMap};
use std::iter::FromIterator;
use std::rc::Rc;
/// The font
#[derive(Debug, Clone, PartialEq)]
pub enum Font {
/// Represents one of the 14 built-in fonts (Arial, Helvetica, etc.)
BuiltinFont(BuiltinFont),
/// Represents a font loaded from an external file
ExternalFont(ExternalFont),
}
/// Standard built-in PDF fonts
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub enum BuiltinFont {
TimesRoman,
TimesBold,
TimesItalic,
TimesBoldItalic,
Helvetica,
HelveticaBold,
HelveticaOblique,
HelveticaBoldOblique,
Courier,
CourierOblique,
CourierBold,
CourierBoldOblique,
Symbol,
ZapfDingbats,
}
impl From<BuiltinFont> for &'static str {
fn from(val: BuiltinFont) -> Self {
use crate::BuiltinFont::*;
match val {
TimesRoman => "Times-Roman",
TimesBold => "Times-Bold",
TimesItalic => "Times-Italic",
TimesBoldItalic => "Times-BoldItalic",
Helvetica => "Helvetica",
HelveticaBold => "Helvetica-Bold",
HelveticaOblique => "Helvetica-Oblique",
HelveticaBoldOblique => "Helvetica-BoldOblique",
Courier => "Courier",
CourierOblique => "Courier-Oblique",
CourierBold => "Courier-Bold",
CourierBoldOblique => "Courier-BoldOblique",
Symbol => "Symbol",
ZapfDingbats => "ZapfDingbats",
}
}
}
impl From<BuiltinFont> for LoDictionary {
fn from(val: BuiltinFont) -> Self {
use lopdf::Object;
use lopdf::Object::*;
let font_id: &'static str = val.into();
// Begin setting required font attributes
let font_vec: Vec<(::std::string::String, Object)> = vec![
("Type".into(), Name("Font".into())),
("Subtype".into(), Name("Type1".into())),
("BaseFont".into(), Name(font_id.into())),
("Encoding".into(), Name("WinAnsiEncoding".into())),
// Missing DescendantFonts and ToUnicode
];
LoDictionary::from_iter(font_vec)
}
}
#[derive(Debug, Clone)]
pub struct ExternalFont {
/// Raw font data
pub(crate) font_bytes: Vec<u8>,
/// Parsed font data
pub(crate) font_data: Box<dyn FontData>,
/// Font name, for adding as a resource on the document
pub(crate) face_name: String,
/// Is the font written vertically? Default: false
pub(crate) vertical_writing: bool,
/// Is the font allowed to be subsetted (removing unused glyphs before embedding)? Default: true
#[allow(unused)]
pub(crate) allow_subsetting: Rc<RefCell<bool>>,
}
/// The text rendering mode determines how a text is drawn
/// The default rendering mode is `Fill`. The color of the
/// fill / stroke is determine by the current pages outline /
/// fill color.
///
/// See PDF Reference 1.7 Page 402
#[derive(Debug, Copy, Clone)]
pub enum TextRenderingMode {
Fill,
Stroke,
FillStroke,
Invisible,
FillClip,
StrokeClip,
FillStrokeClip,
Clip,
}
impl From<TextRenderingMode> for i64 {
fn from(val: TextRenderingMode) -> Self {
use crate::TextRenderingMode::*;
match val {
Fill => 0,
Stroke => 1,
FillStroke => 2,
Invisible => 3,
FillClip => 4,
StrokeClip => 5,
FillStrokeClip => 6,
Clip => 7,
}
}
}
impl ExternalFont {
/// Creates a new font. The `index` is used for naming / identifying the font
///
/// This method uses [`owned_ttf_parser`][] to parse the font data. If you want to use a different
/// font backend, use the [`with_font_data`][] method instead.
///
/// [`owned_ttf_parser`]: https://docs.rs/owned_ttf_parser/latest/owned_ttf_parser/
/// [`with_font_data`]: #method.with_font_data
pub fn new<R>(mut font_stream: R, font_index: usize) -> Result<Self, Error>
where
R: ::std::io::Read,
{
// read font from stream and parse font metrics
let mut buf = Vec::<u8>::new();
font_stream.read_to_end(&mut buf)?;
let font = TtfFace::from_vec(buf.clone())?;
Ok(Self::with_font_data(buf, font_index, Box::new(font)))
}
/// Creates a new font. The `index` is used for naming / identifying the font
pub fn with_font_data(bytes: Vec<u8>, font_index: usize, font_data: Box<dyn FontData>) -> Self {
let face_name = format!("F{font_index}");
Self {
font_bytes: bytes,
font_data,
face_name,
vertical_writing: false,
allow_subsetting: Rc::new(RefCell::new(true)),
}
}
/// Set whether or not to allow subsetting for the font. If subsetting is set to true, unused
/// glyphs will be removed before embedding the font into the PDF file. By default this is set
/// to `true`
#[cfg(feature = "font_subsetting")]
pub fn set_allow_subsetting(&self, allow_subsetting: bool) {
*self.allow_subsetting.borrow_mut() = allow_subsetting;
}
/// Set whether or not to allow subsetting for the font. If subsetting is set to true, unused
/// glyphs will be removed before embedding the font into the PDF file. By default this is set
/// to `true`
#[cfg(feature = "font_subsetting")]
pub fn with_allow_subsetting(self, allow_subsetting: bool) -> Self {
*self.allow_subsetting.borrow_mut() = allow_subsetting;
self
}
/// Iterate through all layers of the provided pages and build a Set of all Glyph IDs that were
/// used at least once
#[cfg(feature = "font_subsetting")]
fn find_used_glyphs(&self, pages: &[PdfPage]) -> std::collections::HashSet<u16> {
// TODO: This is almost the same code as `replace_glyphs`. Somehow reduce redundancy
let mut used_glyphs = std::collections::HashSet::new();
let layers = pages.iter().map(|page| page.layers.iter()).flatten();
for layer in layers {
let operations = layer
.operations
.iter()
.map(|op| (&op.operator, &op.operands));
let mut font_active = false;
for (operator, operands) in operations {
match operator.as_str() {
"Tf" => {
let font_name = operands[0]
.as_name_str()
.expect("PDF Command 'Tf' not followed by Name operand");
font_active = font_name == &self.face_name;
}
"Tj" if font_active => {
let gid_stream = operands[0]
.as_str()
.expect("PDF Command 'Tj' not followed by String operand");
for b in gid_stream.chunks_exact(2) {
let gid = b[1] as u16 | ((b[0] as u16) << 8);
used_glyphs.insert(gid);
}
}
"TJ" if font_active => {
let text_sections = operands[0]
.as_array()
.expect("PDF Command 'TJ' not followed by Array operand")
.into_iter()
.filter_map(|obj| obj.as_str().ok());
for gid_stream in text_sections {
for b in gid_stream.chunks_exact(2) {
let gid = b[1] as u16 | ((b[0] as u16) << 8);
used_glyphs.insert(gid);
}
}
}
_ => (),
}
}
}
used_glyphs
}
/// Iterate through all layers of the provided pages and replace the Glyph ID according to the
/// mapping
#[cfg(feature = "font_subsetting")]
fn replace_glyphs(&self, pages: &mut [PdfPage], gid_mapping: &HashMap<u16, u16>) {
// TODO: This is almost the same code as `find_used_glyphs`. Somehow reduce redundancy
let layers = pages
.iter_mut()
.map(|page| page.layers.iter_mut())
.flatten();
for layer in layers {
let operations = layer
.operations
.iter_mut()
.map(|op| (&mut op.operator, &mut op.operands));
let mut font_active = false;
for (operator, operands) in operations {
match operator.as_str() {
"Tf" => {
let font_name = operands[0]
.as_name_str()
.expect("PDF Command 'Tf' not followed by Name operand");
font_active = font_name == &self.face_name;
}
"Tj" if font_active => {
let gid_stream = operands[0]
.as_str_mut()
.expect("PDF Command 'Tj' not followed by String operand");
for b in gid_stream.chunks_exact_mut(2) {
let gid = b[1] as u16 | ((b[0] as u16) << 8);
let new_gid = gid_mapping.get(&gid).unwrap_or(&0);
b[0] = (new_gid >> 8) as u8;
b[1] = (new_gid & 0xff) as u8;
}
}
"TJ" if font_active => {
let text_sections = operands[0]
.as_array_mut()
.expect("PDF Command 'TJ' not followed by Array operand")
.into_iter()
.filter_map(|obj| obj.as_str_mut().ok());
for gid_stream in text_sections {
for b in gid_stream.chunks_exact_mut(2) {
let gid = b[1] as u16 | ((b[0] as u16) << 8);
let new_gid = gid_mapping.get(&gid).unwrap_or(&0);
b[0] = (new_gid >> 8) as u8;
b[1] = (new_gid & 0xff) as u8;
}
}
}
_ => (),
}
}
}
}
/// Takes the font and adds it to the document and consumes the font.
///
/// Returns None if the font doesn't need to be embedded
pub(crate) fn into_with_document(
self,
doc: &mut lopdf::Document,
_pages: &mut [PdfPage],
) -> Option<LoDictionary> {
use lopdf::Object;
use lopdf::Object::*;
let face_name = self.face_name.clone();
let font_data;
let font_bytes;
#[cfg(feature = "font_subsetting")]
{
if *self.allow_subsetting.borrow() {
let mut used_glyphs = self.find_used_glyphs(_pages);
// Don't include font if none of its glyphs are utilized
if used_glyphs.is_empty() {
return None;
}
// TODO: This is ugly and will silently fall back to no subsetting on errors
match crate::subsetting::subset(&self.font_bytes, &mut used_glyphs) {
Ok(font_subset) => {
match TtfFace::from_vec(font_subset.new_font_bytes.clone()) {
Ok(face) => {
let font: Box<dyn FontData> = Box::new(face);
self.replace_glyphs(_pages, &font_subset.gid_mapping);
font_data = font;
font_bytes = font_subset.new_font_bytes;
}
Err(_) => {
font_data = self.font_data;
font_bytes = self.font_bytes;
}
}
}
Err(_) => {
font_data = self.font_data;
font_bytes = self.font_bytes;
}
}
} else {
font_data = self.font_data;
font_bytes = self.font_bytes;
}
}
#[cfg(not(feature = "font_subsetting"))]
{
font_data = self.font_data;
font_bytes = self.font_bytes;
}
// Extract basic font information
let face_metrics = font_data.font_metrics();
let font_stream = LoStream::new(
LoDictionary::from_iter(vec![("Length1", Integer(font_bytes.len() as i64))]),
font_bytes,
)
.with_compression(false); /* important! font stream must not be compressed! */
// Begin setting required font attributes
let mut font_vec: Vec<(::std::string::String, Object)> = vec![
("Type".into(), Name("Font".into())),
("Subtype".into(), Name("Type0".into())),
("BaseFont".into(), Name(face_name.clone().into_bytes())),
// Identity-H for horizontal writing, Identity-V for vertical writing
("Encoding".into(), Name("Identity-H".into())),
// Missing DescendantFonts and ToUnicode
];
let mut font_descriptor_vec: Vec<(::std::string::String, Object)> = vec![
("Type".into(), Name("FontDescriptor".into())),
("FontName".into(), Name(face_name.clone().into_bytes())),
("Ascent".into(), Integer(i64::from(face_metrics.ascent))),
("Descent".into(), Integer(i64::from(face_metrics.descent))),
("CapHeight".into(), Integer(i64::from(face_metrics.ascent))),
("ItalicAngle".into(), Integer(0)),
("Flags".into(), Integer(32)),
("StemV".into(), Integer(80)),
];
// End setting required font arguments
// Maximum height of a single character in the font
let mut max_height = 0;
// Total width of all characters
let mut total_width = 0;
// Widths (or heights, depends on self.vertical_writing)
// of the individual characters, indexed by glyph id
let mut widths = Vec::<(u32, u32)>::new();
// Glyph IDs - (Unicode IDs - character width, character height)
let mut cmap = BTreeMap::<u32, (u32, u32, u32)>::new();
cmap.insert(0, (0, 1000, 1000));
for (glyph_id, c) in font_data.glyph_ids() {
if let Some(glyph_metrics) = font_data.glyph_metrics(glyph_id) {
if glyph_metrics.height > max_height {
max_height = glyph_metrics.height;
}
total_width += glyph_metrics.width;
cmap.insert(
glyph_id as u32,
(c as u32, glyph_metrics.width, glyph_metrics.height),
);
}
}
// Maps the character index to a unicode value - add this to the "ToUnicode" dictionary!
//
// To explain this structure: Glyph IDs have to be in segments where the first byte of the
// first and last element have to be the same. A range from 0x1000 - 0x10FF is valid
// but a range from 0x1000 - 0x12FF is not (0x10 != 0x12)
// Plus, the maximum number of Glyph-IDs in one range is 100
//
// Since the glyph IDs are sequential, all we really have to do is to enumerate the vector
// and create buckets of 100 / rest to 256 if needed
let mut cur_first_bit: u16 = 0_u16; // current first bit of the glyph id (0x10 or 0x12) for example
let mut all_cmap_blocks = Vec::new();
{
let mut current_cmap_block = Vec::new();
for (glyph_id, unicode_width_tuple) in &cmap {
if (*glyph_id >> 8) as u16 != cur_first_bit || current_cmap_block.len() >= 100 {
// end the current (beginbfchar endbfchar) block
all_cmap_blocks.push(current_cmap_block.clone());
current_cmap_block = Vec::new();
cur_first_bit = (*glyph_id >> 8) as u16;
}
let (unicode, width, _) = *unicode_width_tuple;
current_cmap_block.push((*glyph_id, unicode));
widths.push((*glyph_id, width));
}
all_cmap_blocks.push(current_cmap_block);
}
let cid_to_unicode_map = generate_cid_to_unicode_map(face_name.clone(), all_cmap_blocks);
let cid_to_unicode_map_stream =
LoStream::new(LoDictionary::new(), cid_to_unicode_map.as_bytes().to_vec());
let cid_to_unicode_map_stream_id = doc.add_object(cid_to_unicode_map_stream);
// encode widths / heights so that they fit into what PDF expects
// see page 439 in the PDF 1.7 reference
// basically widths_list will contain objects like this:
// 20 [21, 99, 34, 25]
// which means that the character with the GID 20 has a width of 21 units
// and the character with the GID 21 has a width of 99 units
let mut widths_list = Vec::<Object>::new();
let mut current_low_gid = 0;
let mut current_high_gid = 0;
let mut current_width_vec = Vec::<Object>::new();
// scale the font width so that it sort-of fits into an 1000 unit square
let percentage_font_scaling = 1000.0 / (face_metrics.units_per_em as f32);
for gid in 0..font_data.glyph_count() {
if let Some(GlyphMetrics { width, .. }) = font_data.glyph_metrics(gid) {
if gid == current_high_gid {
current_width_vec
.push(Integer((width as f32 * percentage_font_scaling) as i64));
current_high_gid += 1;
} else {
widths_list.push(Integer(current_low_gid as i64));
widths_list.push(Array(current_width_vec.drain(..).collect()));
current_width_vec
.push(Integer((width as f32 * percentage_font_scaling) as i64));
current_low_gid = gid;
current_high_gid = gid + 1;
}
} else {
continue;
}
}
// push the last widths, because the loop is delayed by one iteration
widths_list.push(Integer(current_low_gid as i64));
widths_list.push(Array(current_width_vec.drain(..).collect()));
let w = {
if self.vertical_writing {
("W2", Array(widths_list))
} else {
("W", Array(widths_list))
}
};
// default width for characters
let dw = {
if self.vertical_writing {
("DW2", Integer(1000))
} else {
("DW", Integer(1000))
}
};
let mut desc_fonts = LoDictionary::from_iter(vec![
("Type", Name("Font".into())),
("Subtype", Name("CIDFontType2".into())),
("BaseFont", Name(face_name.into())),
(
"CIDSystemInfo",
Dictionary(LoDictionary::from_iter(vec![
("Registry", String("Adobe".into(), StringFormat::Literal)),
("Ordering", String("Identity".into(), StringFormat::Literal)),
("Supplement", Integer(0)),
])),
),
w,
dw,
]);
let font_bbox = vec![
Integer(0),
Integer(max_height as i64),
Integer(total_width as i64),
Integer(max_height as i64),
];
font_descriptor_vec.push(("FontFile2".into(), Reference(doc.add_object(font_stream))));
// although the following entry is technically not needed, Adobe Reader needs it
font_descriptor_vec.push(("FontBBox".into(), Array(font_bbox)));
let font_descriptor_vec_id = doc.add_object(LoDictionary::from_iter(font_descriptor_vec));
desc_fonts.set("FontDescriptor", Reference(font_descriptor_vec_id));
font_vec.push((
"DescendantFonts".into(),
Array(vec![Dictionary(desc_fonts)]),
));
font_vec.push(("ToUnicode".into(), Reference(cid_to_unicode_map_stream_id)));
Some(LoDictionary::from_iter(font_vec))
}
}
type GlyphId = u32;
type UnicodeCodePoint = u32;
type CmapBlock = Vec<(GlyphId, UnicodeCodePoint)>;
/// Generates a CMAP (character map) from valid cmap blocks
fn generate_cid_to_unicode_map(face_name: String, all_cmap_blocks: Vec<CmapBlock>) -> String {
let mut cid_to_unicode_map =
format!(include_str!("../assets/gid_to_unicode_beg.txt"), face_name);
for cmap_block in all_cmap_blocks
.into_iter()
.filter(|block| !block.is_empty() || block.len() < 100)
{
cid_to_unicode_map.push_str(format!("{} beginbfchar\r\n", cmap_block.len()).as_str());
for (glyph_id, unicode) in cmap_block {
cid_to_unicode_map.push_str(format!("<{glyph_id:04x}> <{unicode:04x}>\n").as_str());
}
cid_to_unicode_map.push_str("endbfchar\r\n");
}
cid_to_unicode_map.push_str(include_str!("../assets/gid_to_unicode_end.txt"));
cid_to_unicode_map
}
impl PartialEq for ExternalFont {
/// Two fonts are equal if their names are equal, the contents aren't checked
fn eq(&self, other: &ExternalFont) -> bool {
self.face_name == other.face_name
}
}
/// Indexed reference to a font that was added to the document
/// This is a "reference by postscript name"
#[derive(Debug, Hash, Eq, Ord, Clone, PartialEq, PartialOrd)]
pub struct IndirectFontRef {
/// Name of the font (postscript name)
pub(crate) name: String,
}
/// Direct reference (wrapper for `lopdf::Object::Reference`)
/// for increased type safety
#[derive(Debug, Clone)]
pub struct DirectFontRef {
/// Reference to the content in the document stream
pub(crate) inner_obj: lopdf::ObjectId,
/// Actual font data
pub(crate) data: Font,
}
impl IndirectFontRef {
/// Creates a new IndirectFontRef from an index
pub fn new<S>(name: S) -> Self
where
S: Into<String>,
{
Self { name: name.into() }
}
}
/// Font list for tracking fonts within a single PDF document
#[derive(Default, Debug, Clone)]
pub struct FontList {
fonts: BTreeMap<IndirectFontRef, DirectFontRef>,
}
impl FontList {
/// Creates a new FontList
pub fn new() -> Self {
Self::default()
}
/// Adds a font to the FontList
pub fn add_font(&mut self, font_ref: IndirectFontRef, font: DirectFontRef) -> IndirectFontRef {
self.fonts.insert(font_ref.clone(), font);
font_ref
}
/// Turns an indirect font reference into a direct one
/// (Warning): clones the direct font reference
#[inline]
pub fn get_font(&self, font: &IndirectFontRef) -> Option<DirectFontRef> {
self.fonts.get(font).cloned()
}
/// Returns the number of fonts currenly in use
#[inline]
pub fn len(&self) -> usize {
self.fonts.len()
}
/// Returns if the font list is empty
#[inline]
pub fn is_empty(&self) -> bool {
self.fonts.is_empty()
}
/// Converts the fonts into a dictionary
pub(crate) fn into_with_document(
self,
doc: &mut lopdf::Document,
pages: &mut [PdfPage],
) -> lopdf::Dictionary {
let mut font_dict = lopdf::Dictionary::new();
for (indirect_ref, direct_font_ref) in self.fonts {
let font_dict_collected = match direct_font_ref.data {
Font::ExternalFont(font) => match font.into_with_document(doc, pages) {
Some(dict) => dict,
None => continue,
},
Font::BuiltinFont(font) => font.into(),
};
doc.objects.insert(
direct_font_ref.inner_obj,
lopdf::Object::Dictionary(font_dict_collected),
);
font_dict.set(
indirect_ref.name,
lopdf::Object::Reference(direct_font_ref.inner_obj),
);
}
font_dict
}
}
/// The unscaled base metrics for a font provided by a [`FontData`](trait.FontData.html)
/// implementation.
#[derive(Clone, Copy, Debug, Default)]
pub struct FontMetrics {
/// The ascent of the font.
pub ascent: i16,
/// The descent of the font.
pub descent: i16,
/// The units per em square for this font.
pub units_per_em: u16,
}
/// The metrics for a glyph provided by a [`FontData`](trait.FontData.html) implementation.
#[derive(Clone, Copy, Debug, Default)]
pub struct GlyphMetrics {
/// The width of the glyph, typically the horizontal advance.
pub width: u32,
/// The height of the glyph, typically the difference between the ascent and the descent.
pub height: u32,
}
/// Provides access to font metrics.
///
/// Per default, printpdf uses [`owned_ttf_parser`][] to extract the font data. You can implement
/// this trait for other types if you want to use a different font backend.
///
/// [`owned_ttf_parser`]: https://docs.rs/owned_ttf_parser/latest/owned_ttf_parser/
pub trait FontData: FontDataClone + std::fmt::Debug {
/// Returns the unscaled metrics for this font.
fn font_metrics(&self) -> FontMetrics;
/// Returns the glyph id for a Unicode character if it is present in this font.
fn glyph_id(&self, c: char) -> Option<u16>;
/// Returns a mapping from glyph IDs to Unicode characters for all supported characters.
fn glyph_ids(&self) -> HashMap<u16, char>;
/// Returns the number of glyphs in this font.
fn glyph_count(&self) -> u16;
/// Returns the glyph metrics for a glyph of this font, if available.
fn glyph_metrics(&self, glyph_id: u16) -> Option<GlyphMetrics>;
}
/// Wrapper struct for `owned_ttf_parser::OwnedFace` that implements `Clone` and that makes sure
/// that the font is scalable.
#[derive(Clone, Debug)]
struct TtfFace {
inner: std::sync::Arc<OwnedFace>,
units_per_em: u16,
}
impl TtfFace {
pub fn from_vec(v: Vec<u8>) -> Result<Self, Error> {
let face = OwnedFace::from_vec(v, 0)?;
let units_per_em = face.as_face_ref().units_per_em();
Ok(Self {
inner: std::sync::Arc::new(face),
units_per_em,
})
}
fn face(&self) -> &Face<'_> {
self.inner.as_face_ref()
}
}
impl FontData for TtfFace {
fn font_metrics(&self) -> FontMetrics {
FontMetrics {
ascent: self.face().ascender(),
descent: self.face().descender(),
units_per_em: self.units_per_em,
}
}
fn glyph_id(&self, c: char) -> Option<u16> {
self.face().glyph_index(c).map(|id| id.0)
}
fn glyph_ids(&self) -> HashMap<u16, char> {
let subtables = self
.face()
.tables().cmap.map(|cmap| cmap.subtables.into_iter().filter(|v| v.is_unicode()));
let Some(subtables) = subtables else{
return HashMap::new();
};
let mut map = HashMap::with_capacity(self.face().number_of_glyphs().into());
for subtable in subtables {
subtable.codepoints(|c| {
use std::convert::TryFrom as _;
if let Ok(ch) = char::try_from(c) {
if let Some(idx) = subtable.glyph_index(c).filter(|idx| idx.0 > 0) {
map.entry(idx.0).or_insert(ch);
}
}
})
}
map
}
fn glyph_count(&self) -> u16 {
self.face().number_of_glyphs()
}
fn glyph_metrics(&self, glyph_id: u16) -> Option<GlyphMetrics> {
let glyph_id = owned_ttf_parser::GlyphId(glyph_id);
if let Some(width) = self.face().glyph_hor_advance(glyph_id) {
let width = width as u32;
let height = self
.face()
.glyph_bounding_box(glyph_id)
.map(|bbox| bbox.y_max - bbox.y_min - self.face().descender())
.unwrap_or(1000) as u32;
Some(GlyphMetrics { width, height })
} else {
None
}
}
}
/// Helper trait for cloning boxed [`FontData`](trait.FontData.html) implementors.
pub trait FontDataClone {
/// Clones this font data and returns a box with the cloned data.
fn clone_font_data(&self) -> Box<dyn FontData>;
}
impl<T: FontData + Clone + 'static> FontDataClone for T {
fn clone_font_data(&self) -> Box<dyn FontData> {
Box::new(self.clone())
}
}
impl Clone for Box<dyn FontData> {
fn clone(&self) -> Box<dyn FontData> {
self.clone_font_data()
}
}