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fontconfig.rs
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fontconfig.rs
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// font-kit/src/sources/fontconfig.rs
//
// Copyright © 2018 The Pathfinder Project Developers.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! A source that contains the fonts installed on the system, as reported by the Fontconfig
//! library.
//!
//! On macOS and Windows, the Cargo feature `source-fontconfig` can be used to opt into fontconfig
//! support. To prefer it over the native font source (only if you know what you're doing), use the
//! `source-fontconfig-default` feature.
use error::SelectionError;
use family_handle::FamilyHandle;
use family_name::FamilyName;
use handle::Handle;
use properties::Properties;
use source::Source;
/// A source that contains the fonts installed on the system, as reported by the Fontconfig
/// library.
///
/// On macOS and Windows, the Cargo feature `source-fontconfig` can be used to opt into fontconfig
/// support. To prefer it over the native font source (only if you know what you're doing), use the
/// `source-fontconfig-default` feature.
pub struct FontconfigSource {
config: fc::Config,
}
impl FontconfigSource {
/// Initializes Fontconfig and prepares it for queries.
pub fn new() -> FontconfigSource {
FontconfigSource {
config: fc::Config::new(),
}
}
/// Returns the names of all families installed on the system.
pub fn all_families(&self) -> Result<Vec<String>, SelectionError> {
let pattern = fc::Pattern::new();
// We want the family name.
let mut object_set = fc::ObjectSet::new();
object_set.push_string(fc::Object::Family);
let patterns = pattern.list(Some(&self.config), object_set)
.map_err(|_| SelectionError::NotFound)?;
let mut result_families = vec![];
for patt in patterns {
if let Some(family) = patt.get_string(fc::Object::Family) {
result_families.push(family);
}
}
result_families.sort();
result_families.dedup();
if !result_families.is_empty() {
Ok(result_families)
} else {
Err(SelectionError::NotFound)
}
}
/// Looks up a font family by name and returns the handles of all the fonts in that family.
pub fn select_family_by_name(&self, family_name: &str)
-> Result<FamilyHandle, SelectionError> {
let mut pattern = fc::Pattern::from_name(family_name);
pattern.config_substitute(None, fc::MatchKind::Pattern);
pattern.default_substitute();
let patterns = pattern.sorted(None).map_err(|_| SelectionError::NotFound)?;
let mut handles = Vec::new();
for patt in patterns {
let font_path = patt.get_string(fc::Object::File).unwrap();
let font_index = patt.get_integer(fc::Object::Index).unwrap() as u32;
let handle = Handle::from_path(std::path::PathBuf::from(font_path), font_index);
handles.push(handle);
}
if !handles.is_empty() {
Ok(FamilyHandle::from_font_handles(handles.into_iter()))
} else {
Err(SelectionError::NotFound)
}
}
/// Selects a font by PostScript name, which should be a unique identifier.
///
/// The default implementation, which is used by the DirectWrite and the filesystem backends,
/// does a brute-force search of installed fonts to find the one that matches.
pub fn select_by_postscript_name(&self, postscript_name: &str)
-> Result<Handle, SelectionError> {
let mut pattern = fc::Pattern::new();
pattern.push_string(fc::Object::PostScriptName, postscript_name.to_owned());
// We want the file path and the font index.
let mut object_set = fc::ObjectSet::new();
object_set.push_string(fc::Object::File);
object_set.push_string(fc::Object::Index);
let patterns = pattern.list(Some(&self.config), object_set)
.map_err(|_| SelectionError::NotFound)?;
if let Some(patt) = patterns.into_iter().next() {
let font_path = patt.get_string(fc::Object::File).unwrap();
let font_index = patt.get_integer(fc::Object::Index).unwrap() as u32;
let handle = Handle::from_path(std::path::PathBuf::from(font_path), font_index);
Ok(handle)
} else {
Err(SelectionError::NotFound)
}
}
/// Performs font matching according to the CSS Fonts Level 3 specification and returns the
/// handle.
#[inline]
pub fn select_best_match(&self, family_names: &[FamilyName], properties: &Properties)
-> Result<Handle, SelectionError> {
<Self as Source>::select_best_match(self, family_names, properties)
}
}
impl Source for FontconfigSource {
#[inline]
fn all_families(&self) -> Result<Vec<String>, SelectionError> {
self.all_families()
}
#[inline]
fn select_family_by_name(&self, family_name: &str) -> Result<FamilyHandle, SelectionError> {
self.select_family_by_name(family_name)
}
#[inline]
fn select_by_postscript_name(&self, postscript_name: &str) -> Result<Handle, SelectionError> {
self.select_by_postscript_name(postscript_name)
}
}
// TODO: move to a separate crate
mod fc {
#![allow(dead_code)]
use fontconfig::fontconfig as ffi;
use std::ffi::{CStr, CString};
use std::os::raw::{c_char, c_uchar};
use std::ptr;
#[derive(Clone, Copy)]
pub enum Error {
NoMatch,
TypeMismatch,
NoId,
OutOfMemory,
}
#[derive(Clone, Copy)]
pub enum MatchKind {
Pattern,
Font,
Scan,
}
impl MatchKind {
fn to_u32(&self) -> u32 {
match self {
MatchKind::Pattern => ffi::FcMatchPattern,
MatchKind::Font => ffi::FcMatchFont,
MatchKind::Scan => ffi::FcMatchScan,
}
}
}
// https://www.freedesktop.org/software/fontconfig/fontconfig-devel/x19.html
#[derive(Clone, Copy)]
pub enum Object {
Family,
File,
Index,
PostScriptName,
}
impl Object {
fn as_bytes(&self) -> &[u8] {
match self {
Object::Family => b"family\0",
Object::File => b"file\0",
Object::Index => b"index\0",
Object::PostScriptName => b"postscriptname\0",
}
}
fn as_ptr(&self) -> *const libc::c_char {
self.as_bytes().as_ptr() as *const libc::c_char
}
}
pub struct Config {
d: *mut ffi::FcConfig,
}
impl Config {
// FcInitLoadConfigAndFonts
pub fn new() -> Self {
unsafe {
Config {
d: ffi::FcInitLoadConfigAndFonts(),
}
}
}
}
pub struct Pattern {
d: *mut ffi::FcPattern,
c_strings: Vec<CString>,
}
impl Pattern {
fn from_ptr(d: *mut ffi::FcPattern) -> Self {
Pattern {
d,
c_strings: vec![],
}
}
// FcPatternCreate
pub fn new() -> Self {
unsafe {
Pattern::from_ptr(ffi::FcPatternCreate())
}
}
// FcNameParse
pub fn from_name(name: &str) -> Self {
let c_name = CString::new(name).unwrap();
unsafe {
Pattern::from_ptr(ffi::FcNameParse(c_name.as_ptr() as *mut c_uchar))
}
}
// FcPatternAddString
pub fn push_string(&mut self, object: Object, value: String) {
unsafe {
let c_string = CString::new(value).unwrap();
ffi::FcPatternAddString(
self.d,
object.as_ptr(),
c_string.as_ptr() as *const c_uchar,
);
// We have to keep this string, because `FcPattern` has a pointer to it now.
self.c_strings.push(c_string)
}
}
// FcConfigSubstitute
pub fn config_substitute(&mut self, config: Option<Config>, match_kind: MatchKind) {
let config = config.map(|c| c.d).unwrap_or(ptr::null_mut());
unsafe {
ffi::FcConfigSubstitute(config, self.d, match_kind.to_u32());
}
}
// FcDefaultSubstitute
pub fn default_substitute(&mut self) {
unsafe {
ffi::FcDefaultSubstitute(self.d);
}
}
// FcFontSort
pub fn sorted(&self, config: Option<Config>) -> Result<FontSet, Error> {
let config = config.map(|c| c.d).unwrap_or(ptr::null_mut());
let mut res = ffi::FcResultMatch;
let d = unsafe {
ffi::FcFontSort(config, self.d, 1, ptr::null_mut(), &mut res)
};
match res {
ffi::FcResultMatch => Ok(FontSet { d, idx: 0 }),
ffi::FcResultTypeMismatch => Err(Error::TypeMismatch),
ffi::FcResultNoId => Err(Error::NoId),
ffi::FcResultOutOfMemory => Err(Error::OutOfMemory),
_ => Err(Error::NoMatch),
}
}
// FcFontList
pub fn list(&self, config: Option<&Config>, set: ObjectSet) -> Result<FontSet, Error> {
let config = config.map(|c| c.d).unwrap_or(ptr::null_mut());
let d = unsafe { ffi::FcFontList(config, self.d, set.d) };
if !d.is_null() {
Ok(FontSet { d, idx: 0 })
} else {
Err(Error::NoMatch)
}
}
}
impl Drop for Pattern {
#[inline]
fn drop(&mut self) {
unsafe {
ffi::FcPatternDestroy(self.d)
}
}
}
// A read-only `FcPattern` without a destructor.
pub struct PatternRef {
d: *mut ffi::FcPattern,
}
impl PatternRef {
// FcPatternGetString
pub fn get_string(&self, object: Object) -> Option<String> {
unsafe {
let mut string = ptr::null_mut();
let res = ffi::FcPatternGetString(self.d, object.as_ptr(), 0, &mut string);
if res != ffi::FcResultMatch {
return None
}
if string.is_null() {
return None
}
CStr::from_ptr(string as *const c_char).to_str()
.ok().map(|string| string.to_owned())
}
}
// FcPatternGetInteger
pub fn get_integer(&self, object: Object) -> Option<i32> {
unsafe {
let mut integer = 0;
let res = ffi::FcPatternGetInteger(self.d, object.as_ptr(), 0, &mut integer);
if res != ffi::FcResultMatch {
return None
}
Some(integer)
}
}
}
pub struct FontSet {
d: *mut ffi::FcFontSet,
idx: usize,
}
impl FontSet {
pub fn is_empty(&self) -> bool {
self.len() == 0
}
pub fn len(&self) -> usize {
unsafe {
(*self.d).nfont as usize
}
}
}
impl Iterator for FontSet {
type Item = PatternRef;
fn next(&mut self) -> Option<Self::Item> {
if self.idx == self.len() {
return None;
}
let idx = self.idx;
self.idx += 1;
let d = unsafe { *(*self.d).fonts.offset(idx as isize) };
Some(PatternRef { d })
}
fn size_hint(&self) -> (usize, Option<usize>) {
(0, Some(self.len()))
}
}
impl Drop for FontSet {
fn drop(&mut self) {
unsafe {
ffi::FcFontSetDestroy(self.d)
}
}
}
pub struct ObjectSet {
d: *mut ffi::FcObjectSet,
}
impl ObjectSet {
// FcObjectSetCreate
pub fn new() -> Self {
unsafe {
ObjectSet { d: ffi::FcObjectSetCreate() }
}
}
// FcObjectSetAdd
pub fn push_string(&mut self, object: Object) {
unsafe {
// Returns `false` if the property name cannot be inserted
// into the set (due to allocation failure).
assert_eq!(ffi::FcObjectSetAdd(self.d, object.as_ptr()), 1);
}
}
}
impl Drop for ObjectSet {
fn drop(&mut self) {
unsafe {
ffi::FcObjectSetDestroy(self.d)
}
}
}
}