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//! Bindings for [`AFont`], [`AFontMatcher`], and [`ASystemFontIterator`]
//!
//! [`AFont`]: https://developer.android.com/ndk/reference/group/font
//! [`AFontMatcher`]: https://developer.android.com/ndk/reference/group/font#afontmatcher_create
//! [`ASystemFontIterator`]: https://developer.android.com/ndk/reference/group/font#asystemfontiterator_open
#![cfg(feature = "api-level-29")]
use std::convert::TryFrom;
use std::ffi::{CStr, OsStr};
use std::fmt::{self, Write};
use std::os::unix::prelude::OsStrExt;
use std::path::Path;
use std::ptr::NonNull;
use num_enum::IntoPrimitive;
/// An integer holding a valid font weight value between 1 and 1000.
///
/// See the [`Font::weight`] definition for more details.
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
pub struct FontWeight(u16);
impl FontWeight {
pub const fn new(value: u16) -> Result<Self, FontWeightValueError> {
if Self::MIN.0 <= value && value <= Self::MAX.0 {
Ok(Self(value))
} else {
Err(FontWeightValueError(()))
}
}
pub const fn to_u16(self) -> u16 {
self.0
}
/// The minimum value for the font weight value. Unlike [`ffi::AFONT_WEIGHT_MIN`] being `0`,
/// [`FontWeight::MIN`] is `1` to make the `MIN..MAX` range be inclusive, keeping consistency
/// between [`FontWeight`] and other types like `std::num::NonZeroU*`.
pub const MIN: FontWeight = FontWeight(ffi::AFONT_WEIGHT_MIN as u16 + 1);
/// A font weight value for the thin weight.
pub const THIN: FontWeight = FontWeight(ffi::AFONT_WEIGHT_THIN as u16);
/// A font weight value for the extra-light weight.
pub const EXTRA_LIGHT: FontWeight = FontWeight(ffi::AFONT_WEIGHT_EXTRA_LIGHT as u16);
/// A font weight value for the light weight.
pub const LIGHT: FontWeight = FontWeight(ffi::AFONT_WEIGHT_LIGHT as u16);
/// A font weight value for the normal weight.
pub const NORMAL: FontWeight = FontWeight(ffi::AFONT_WEIGHT_NORMAL as u16);
/// A font weight value for the medium weight.
pub const MEDIUM: FontWeight = FontWeight(ffi::AFONT_WEIGHT_MEDIUM as u16);
/// A font weight value for the semi-bold weight.
pub const SEMI_BOLD: FontWeight = FontWeight(ffi::AFONT_WEIGHT_SEMI_BOLD as u16);
/// A font weight value for the bold weight.
pub const BOLD: FontWeight = FontWeight(ffi::AFONT_WEIGHT_BOLD as u16);
/// A font weight value for the extra-bold weight.
pub const EXTRA_BOLD: FontWeight = FontWeight(ffi::AFONT_WEIGHT_EXTRA_BOLD as u16);
/// A font weight value for the black weight.
pub const BLACK: FontWeight = FontWeight(ffi::AFONT_WEIGHT_BLACK as u16);
/// The maximum value for the font weight value.
pub const MAX: FontWeight = FontWeight(ffi::AFONT_WEIGHT_MAX as u16);
}
impl fmt::Display for FontWeight {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(match *self {
FontWeight::THIN => "Thin",
FontWeight::EXTRA_LIGHT => "Extra Light (Ultra Light)",
FontWeight::LIGHT => "Light",
FontWeight::NORMAL => "Normal (Regular)",
FontWeight::MEDIUM => "Medium",
FontWeight::SEMI_BOLD => "Semi Bold (Demi Bold)",
FontWeight::BOLD => "Bold",
FontWeight::EXTRA_BOLD => "Extra Bold (Ultra Bold)",
FontWeight::BLACK => "Black (Heavy)",
_ => return writeln!(f, "{}", self.0),
})
}
}
/// The error type returned when an invalid font weight value is passed.
#[derive(Debug)]
pub struct FontWeightValueError(());
impl fmt::Display for FontWeightValueError {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.write_str("font weight must be positive and less than or equal to 1000")
}
}
impl std::error::Error for FontWeightValueError {}
impl TryFrom<u16> for FontWeight {
type Error = FontWeightValueError;
fn try_from(value: u16) -> Result<Self, Self::Error> {
FontWeight::new(value)
}
}
/// A 4-byte integer representing an OpenType axis tag.
#[derive(Clone, Copy, PartialEq, Eq)]
pub struct AxisTag(u32);
impl AxisTag {
/// Checks whether the given 4-byte array can construct a valid axis tag and returns
/// [`Ok(AxisTag)`] if the array is valid.
///
/// Each byte in a tag must be in the range 0x20 to 0x7E. A space character cannot be followed
/// by a non-space character. A tag must have one to four non-space characters. See the
/// [OpenType spec] for more details.
///
/// [OpenType spec]: https://learn.microsoft.com/en-us/typography/opentype/spec/otff#data-types
pub const fn from_be_bytes_checked(value: [u8; 4]) -> Result<Self, AxisTagValueError> {
// Each byte in a tag must be in the range 0x20 to 0x7E.
macro_rules! check_byte_range {
($($e:expr)+) => {
$(
if !(value[$e] as char).is_ascii_graphic() && value[$e] != b' ' {
return Err(AxisTagValueError::InvalidCharacter);
}
)+
};
}
check_byte_range!(0 1 2 3);
if value[0] == b' ' {
return Err(
if value[1] == b' ' && value[2] == b' ' && value[3] == b' ' {
// A tag must have one to four non-space characters.
AxisTagValueError::EmptyTag
} else {
// A space character cannot be followed by a non-space character.
AxisTagValueError::InvalidSpacePadding
},
);
}
macro_rules! check_if_valid {
($e:expr ; $($f:expr)+) => {
if value[$e] == b' ' {
return if true $(&& value[$f] == b' ')+ {
Ok(Self(u32::from_be_bytes(value)))
} else {
// A space character cannot be followed by a non-space character.
Err(AxisTagValueError::InvalidSpacePadding)
};
}
};
}
check_if_valid!(1; 2 3);
check_if_valid!(2; 3);
// Whether or not value[3] is b' ', value is a valid axis tag.
Ok(Self(u32::from_be_bytes(value)))
}
/// Checks whether the given 4-byte array can construct a valid axis tag and returns
/// [`Ok(AxisTag)`] if the array is valid.
///
/// See [`AxisTag::from_be()`] for more details.
pub const fn from_be_checked(value: u32) -> Result<Self, AxisTagValueError> {
Self::from_be_bytes_checked(value.to_be_bytes())
}
/// Construct an axis tag from the given 4-byte array. If the resulting axis tag is invalid,
/// this function panics.
///
/// See [`AxisTag::from_be()`] for more details.
pub const fn from_be_bytes(value: [u8; 4]) -> Self {
Self::unwrap_result(Self::from_be_bytes_checked(value))
}
/// Construct an axis tag from the given 4-byte integer. If the resulting axis tag is invalid,
/// this function panics.
///
/// See [`AxisTag::from_be()`] for more details.
pub const fn from_be(value: u32) -> Self {
Self::unwrap_result(Self::from_be_checked(value))
}
/// const-version of [`Result::unwrap`]. Should be removed when [`Option::unwrap`] or
/// [`Result::unwrap`] become `const`-stable.
const fn unwrap_result(result: Result<Self, AxisTagValueError>) -> Self {
match result {
Ok(t) => t,
Err(e) => panic!("{}", e.as_str()),
}
}
pub const fn to_u32(self) -> u32 {
self.0
}
pub const fn to_be_bytes(self) -> [u8; 4] {
self.0.to_be_bytes()
}
}
impl fmt::Display for AxisTag {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let bytes = self.to_be_bytes();
f.write_char(bytes[0] as char)?;
f.write_char(bytes[1] as char)?;
f.write_char(bytes[2] as char)?;
f.write_char(bytes[3] as char)
}
}
impl fmt::Debug for AxisTag {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "AxisTag({} {:#x})", self, self.0)
}
}
/// The error type returned when an invalid axis tag value is passed.
#[derive(Clone, Copy, Debug)]
pub enum AxisTagValueError {
/// There is a byte not in the range 0x20 to 0x7E.
InvalidCharacter,
/// There is a space character followed by a non-space character.
InvalidSpacePadding,
/// The tag only consists of space characters.
EmptyTag,
}
impl AxisTagValueError {
pub const fn as_str(&self) -> &'static str {
match self {
Self::InvalidCharacter => "each byte in an axis tag must be in the range 0x20 to 0x7E",
Self::InvalidSpacePadding => {
"a space character cannot be followed by a non-space character"
}
Self::EmptyTag => "a tag must have one to four non-space characters",
}
}
}
impl fmt::Display for AxisTagValueError {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.write_str(self.as_str())
}
}
impl std::error::Error for AxisTagValueError {}
/// A native [`AFont *`]
///
/// [`AFont *`]: https://developer.android.com/ndk/reference/group/font
#[derive(Debug)]
pub struct Font {
ptr: NonNull<ffi::AFont>,
}
impl Font {
/// Assumes ownership of `ptr`.
///
/// # Safety
/// `ptr` must be a valid owning pointer to an Android [`ffi::AFont`].
pub unsafe fn from_ptr(ptr: NonNull<ffi::AFont>) -> Self {
Self { ptr }
}
/// Returns s the pointer to the native [`ffi::AFont`].
pub fn ptr(&self) -> NonNull<ffi::AFont> {
self.ptr
}
/// Returns a count of font variation settings associated with the current font.
///
/// The font variation settings are provided as multiple tag-value pairs.
///
/// For example, bold italic font may have following font variation settings: `'wght' 700`,
/// `'slnt' -12`. In this case, [`Font::axis_count()`] returns `2` and [`Font::axis_tag_at()`] and
/// [`Font::axis_value_at()`] return those variation names and the corresponding values.
///
/// ```no_run
/// use ndk::font::Font;
///
/// let font: Font = todo!();
/// for idx in 0..font.axis_count() {
/// log::debug!("{}: {}", font.axis_tag_at(idx), font.axis_value_at(idx));
/// }
/// // Output:
/// // wght: 700
/// // slnt: -12
/// ```
pub fn axis_count(&self) -> usize {
unsafe { ffi::AFont_getAxisCount(self.ptr.as_ptr()) }
}
/// Returns an OpenType axis tag associated with the current font.
///
/// See [`Font::axis_count()`] for more details.
pub fn axis_tag_at(&self, idx: usize) -> AxisTag {
// Android returns Axis Tag in big-endian.
// See https://cs.android.com/android/platform/superproject/+/refs/heads/master:frameworks/base/native/android/system_fonts.cpp;l=197 for details
AxisTag(unsafe { ffi::AFont_getAxisTag(self.ptr.as_ptr(), idx as u32) })
}
/// Returns an OpenType axis value associated with the current font.
///
/// See [`Font::axis_count()`] for more details.
pub fn axis_value_at(&self, idx: usize) -> f32 {
unsafe { ffi::AFont_getAxisValue(self.ptr.as_ptr(), idx as u32) }
}
/// Returns a font collection index value associated with the current font.
///
/// In case the target font file is a font collection (e.g. `.ttc` or `.otc`), this returns a
/// non-negative value as a font offset in the collection. This always returns 0 if the target
/// font file is a regular font.
pub fn collection_index(&self) -> usize {
unsafe { ffi::AFont_getCollectionIndex(self.ptr.as_ptr()) }
}
/// Returns an absolute path to the current font file.
///
/// Here is a list of font formats returned by this method:
///
/// * OpenType
/// * OpenType Font Collection
/// * TrueType
/// * TrueType Collection
///
/// The file extension could be one of `*.otf`, `*.ttf`, `*.otc` or `*.ttc`.
/// The font file specified by the returned path is guaranteed to be openable with `O_RDONLY`.
pub fn path(&self) -> &Path {
let path = unsafe { CStr::from_ptr(ffi::AFont_getFontFilePath(self.ptr.as_ptr())) };
OsStr::from_bytes(path.to_bytes()).as_ref()
}
/// Returns an IETF BCP47 compliant language tag associated with the current font.
///
/// For information about IETF BCP47, read [`Locale.forLanguageTag(java.lang.String)`].
///
/// [`Locale.forLanguageTag(java.lang.String)`]: https://developer.android.com/reference/java/util/Locale.html#forLanguageTag(java.lang.String)
pub fn locale(&self) -> Option<&CStr> {
let ptr = unsafe { ffi::AFont_getLocale(self.ptr.as_ptr()) };
if ptr.is_null() {
None
} else {
Some(unsafe { CStr::from_ptr(ptr) })
}
}
/// Returns a weight value associated with the current font.
///
/// The weight values are positive and less than or equal to 1000. Here are pairs of the common
/// names and their values.
///
/// | Value | Name | NDK Definition |
/// | ----- | ------------------------- | --------------------------- |
/// | 100 | Thin | [`FontWeight::THIN`] |
/// | 200 | Extra Light (Ultra Light) | [`FontWeight::EXTRA_LIGHT`] |
/// | 300 | Light | [`FontWeight::LIGHT`] |
/// | 400 | Normal (Regular) | [`FontWeight::NORMAL`] |
/// | 500 | Medium | [`FontWeight::MEDIUM`] |
/// | 600 | Semi Bold (Demi Bold) | [`FontWeight::SEMI_BOLD`] |
/// | 700 | Bold | [`FontWeight::BOLD`] |
/// | 800 | Extra Bold (Ultra Bold) | [`FontWeight::EXTRA_BOLD`] |
/// | 900 | Black (Heavy) | [`FontWeight::BLACK`] |
pub fn weight(&self) -> FontWeight {
FontWeight(unsafe { ffi::AFont_getWeight(self.ptr.as_ptr()) })
}
/// Returns [`true`] if the current font is italic, otherwise returns [`false`].
pub fn is_italic(&self) -> bool {
unsafe { ffi::AFont_isItalic(self.ptr.as_ptr()) }
}
}
impl Drop for Font {
fn drop(&mut self) {
unsafe { ffi::AFont_close(self.ptr.as_ptr()) }
}
}
/// Corresponds to [`AFAMILY_VARIANT_*`].
///
/// [`AFAMILY_VARIANT_*`]: https://developer.android.com/ndk/reference/group/font#group___font_1gga96a58e29e8dbf2b5bdeb775cba46556ea662aafc7016e35d6758da93416fc0833
#[repr(u32)]
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, IntoPrimitive)]
#[non_exhaustive]
pub enum FamilyVariant {
/// A family variant value for the compact font family variant.
/// The compact font family has Latin-based vertical metrics.
Compact = ffi::AFAMILY_VARIANT_COMPACT,
/// A family variant value for the system default variant.
Default = ffi::AFAMILY_VARIANT_DEFAULT,
/// A family variant value for the elegant font family variant.
/// The elegant font family may have larger vertical metrics than Latin font.
Elegant = ffi::AFAMILY_VARIANT_ELEGANT,
#[doc(hidden)]
#[num_enum(catch_all)]
__Unknown(u32),
}
/// A native [`AFontMatcher *`]
///
/// [`AFontMatcher *`]: https://developer.android.com/ndk/reference/group/font#afontmatcher_create
#[derive(Debug)]
pub struct FontMatcher {
ptr: NonNull<ffi::AFontMatcher>,
}
impl FontMatcher {
/// Assumes ownership of `ptr`.
///
/// # Safety
/// `ptr` must be a valid owning pointer to an Android [`ffi::AFontMatcher`].
pub unsafe fn from_ptr(ptr: NonNull<ffi::AFontMatcher>) -> Self {
Self { ptr }
}
/// Returns s the pointer to the native [`ffi::AFontMatcher`].
pub fn ptr(&self) -> NonNull<ffi::AFontMatcher> {
self.ptr
}
/// Creates a new [`FontMatcher`] object. [`FontMatcher`] selects the best font from the
/// parameters set by the user.
pub fn new() -> Self {
let ptr = NonNull::new(unsafe { ffi::AFontMatcher_create() })
.expect("AFontMatcher_create returned NULL");
unsafe { FontMatcher::from_ptr(ptr) }
}
/// Performs the matching from the generic font family for the text and select one font.
///
/// For more information about generic font families, please read the
/// [W3C spec](https://www.w3.org/TR/css-fonts-4/#generic-font-families).
///
/// Even if no font can render the given text, this function will return a non-null result for
/// drawing Tofu character.
///
/// # Parameters
///
/// - `family_name`: A font family name.
/// - `text`: A UTF-16 encoded text buffer to be rendered. If an empty string is given, this
/// function will panic.
/// - `run_length_out`: Set this to [`Some`] if you want to get the length of the text run with
/// the font returned.
pub fn match_font(
&mut self,
family_name: &CStr,
text: &[u16],
run_length_out: Option<&mut u32>,
) -> Font {
if text.is_empty() {
panic!("text is empty");
}
unsafe {
Font::from_ptr(
NonNull::new(ffi::AFontMatcher_match(
self.ptr.as_ptr(),
family_name.as_ptr(),
text.as_ptr(),
text.len() as _,
run_length_out.map_or(std::ptr::null_mut(), |u| u),
))
.expect("AFontMatcher_match returned NULL"),
)
}
}
/// Sets the family variant of the font to be matched.
///
/// If this function is not called, the match is performed with [`FamilyVariant::Default`].
pub fn set_family_variant(&mut self, family_variant: FamilyVariant) {
unsafe { ffi::AFontMatcher_setFamilyVariant(self.ptr.as_ptr(), family_variant.into()) }
}
/// Sets the locale of the font to be matched.
///
/// If this function is not called, the match is performed with an empty locale list.
///
/// # Parameters
///
/// - `language_tags`: comma separated IETF BCP47 compliant language tags.
pub fn set_locales(&mut self, language_tags: &CStr) {
unsafe { ffi::AFontMatcher_setLocales(self.ptr.as_ptr(), language_tags.as_ptr()) }
}
/// Sets the style of the font to be matched.
///
/// If this function is not called, the match is performed with [`FontWeight::NORMAL`] with non-italic style.
pub fn set_style(&mut self, weight: FontWeight, italic: bool) {
unsafe { ffi::AFontMatcher_setStyle(self.ptr.as_ptr(), weight.to_u16(), italic) }
}
}
impl Drop for FontMatcher {
fn drop(&mut self) {
unsafe { ffi::AFontMatcher_destroy(self.ptr.as_ptr()) }
}
}
/// A native [`ASystemFontIterator *`]
///
/// [`ASystemFontIterator *`]: https://developer.android.com/ndk/reference/group/font#asystemfontiterator_open
#[derive(Debug)]
pub struct SystemFontIterator {
ptr: NonNull<ffi::ASystemFontIterator>,
}
impl SystemFontIterator {
/// Assumes ownership of `ptr`.
///
/// # Safety
/// `ptr` must be a valid owning pointer to an Android [`ffi::ASystemFontIterator`].
pub unsafe fn from_ptr(ptr: NonNull<ffi::ASystemFontIterator>) -> Self {
Self { ptr }
}
/// Returns the pointer to the native [`ffi::ASystemFontIterator`].
pub fn ptr(&self) -> NonNull<ffi::ASystemFontIterator> {
self.ptr
}
/// Creates a system font iterator.
pub fn new() -> Option<Self> {
NonNull::new(unsafe { ffi::ASystemFontIterator_open() })
.map(|p| unsafe { SystemFontIterator::from_ptr(p) })
}
}
impl Iterator for SystemFontIterator {
type Item = Font;
fn next(&mut self) -> Option<Self::Item> {
NonNull::new(unsafe { ffi::ASystemFontIterator_next(self.ptr.as_ptr()) })
.map(|p| unsafe { Font::from_ptr(p) })
}
}
impl Drop for SystemFontIterator {
fn drop(&mut self) {
unsafe { ffi::ASystemFontIterator_close(self.ptr.as_ptr()) }
}
}