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use std::hash::{
BuildHasher,
Hasher,
RandomState,
};
use ratatui::{
buffer::Cell,
style::Modifier,
};
use rustybuzz::Face;
/// A Font which can be used for rendering.
#[derive(Clone)]
pub struct Font<'a> {
font: Face<'a>,
advance: f32,
id: u64,
}
impl<'a> Font<'a> {
/// Create a new Font from data. Returns [`None`] if the font cannot
/// be parsed.
pub fn new(data: &'a [u8]) -> Option<Self> {
let mut hasher = RandomState::new().build_hasher();
hasher.write(data);
Face::from_slice(data, 0).map(|font| {
let advance = font
.glyph_hor_advance(font.glyph_index('m').unwrap_or_default())
.unwrap_or_default() as f32;
Self {
font,
advance,
id: hasher.finish(),
}
})
}
}
impl Font<'_> {
pub(crate) fn id(&self) -> u64 {
self.id
}
pub(crate) fn font(&self) -> &Face {
&self.font
}
pub(crate) fn char_width(&self, height_px: u32) -> u32 {
let scale = height_px as f32 / self.font.height() as f32;
(self.advance * scale) as u32
}
}
/// A collection of fonts to use for rendering. Supports font fallback.
///
/// It is recommended, but not required, that all fonts have the same/very
/// similar aspect ratio, or you may get unexpected results during rendering due
/// to fallback.
pub struct Fonts<'a> {
char_width: u32,
char_height: u32,
last_resort: Font<'a>,
regular: Vec<Font<'a>>,
bold: Vec<Font<'a>>,
italic: Vec<Font<'a>>,
bold_italic: Vec<Font<'a>>,
}
impl<'a> Fonts<'a> {
/// Create a new, empty set of fonts. The provided font will be used as a
/// last-resort fallback if no other fonts can render a particular
/// character. Rendering will attempt to fake bold/italic styles using this
/// font where appropriate.
///
/// The provided size_px will be the rendered height in pixels of all fonts
/// in this collection.
pub fn new(font: Font<'a>, size_px: u32) -> Self {
Self {
char_width: font.char_width(size_px),
char_height: size_px,
last_resort: font,
regular: vec![],
bold: vec![],
italic: vec![],
bold_italic: vec![],
}
}
/// The height (in pixels) of all fonts.
#[inline]
pub fn height_px(&self) -> u32 {
self.char_height
}
/// Change the height of all fonts in this collection to the specified
/// height in pixels.
pub fn set_size_px(&mut self, height_px: u32) {
self.char_height = height_px;
self.char_width = std::iter::once(&self.last_resort)
.chain(self.regular.iter())
.chain(self.bold.iter())
.chain(self.italic.iter())
.chain(self.bold_italic.iter())
.map(|font| font.char_width(height_px))
.min()
.unwrap_or_default();
}
/// Add a collection of fonts for various styles. They will automatically be
/// added to the appropriate fallback font list based on the font's
/// bold/italic properties. Note that this will automatically organize fonts
/// by relative width in order to optimize fallback rendering quality. The
/// ordering of already provided fonts will remain unchanged.
pub fn add_fonts(&mut self, fonts: impl IntoIterator<Item = Font<'a>>) {
let bold_italic_len = self.bold_italic.len();
let italic_len = self.italic.len();
let bold_len = self.bold.len();
let regular_len = self.regular.len();
for font in fonts {
if !font.font().is_monospaced() {
warn!("Non monospace font used in add_fonts, this may cause unexpected rendering.");
}
self.char_width = self.char_width.min(font.char_width(self.char_height));
if font.font().is_italic() && font.font().is_bold() {
self.bold_italic.push(font);
} else if font.font().is_italic() {
self.italic.push(font);
} else if font.font().is_bold() {
self.bold.push(font);
} else {
self.regular.push(font);
}
}
self.bold_italic[bold_italic_len..].sort_by_key(|font| font.char_width(self.char_height));
self.italic[italic_len..].sort_by_key(|font| font.char_width(self.char_height));
self.bold[bold_len..].sort_by_key(|font| font.char_width(self.char_height));
self.regular[regular_len..].sort_by_key(|font| font.char_width(self.char_height));
}
/// Add a new collection of fonts for regular styled text. These fonts will
/// come _after_ previously provided fonts in the fallback order.
pub fn add_regular_fonts(&mut self, fonts: impl IntoIterator<Item = Font<'a>>) {
self.char_width = self.char_width.min(Self::add_fonts_internal(
&mut self.regular,
fonts,
self.char_height,
));
}
/// Add a new collection of fonts for bold styled text. These fonts will
/// come _after_ previously provided fonts in the fallback order.
///
/// You do not have to provide these for bold text to be supported. If no
/// bold fonts are supplied, rendering will fallback to the regular fonts
/// with fake bolding.
pub fn add_bold_fonts(&mut self, fonts: impl IntoIterator<Item = Font<'a>>) {
self.char_width = self.char_width.min(Self::add_fonts_internal(
&mut self.bold,
fonts,
self.char_height,
));
}
/// Add a new collection of fonts for italic styled text. These fonts will
/// come _after_ previously provided fonts in the fallback order.
///
/// It is recommended, but not required, that you provide italic fonts if
/// your application intends to make use of italics. If no italic fonts
/// are supplied, rendering will fallback to the regular fonts with fake
/// italics.
pub fn add_italic_fonts(&mut self, fonts: impl IntoIterator<Item = Font<'a>>) {
self.char_width = self.char_width.min(Self::add_fonts_internal(
&mut self.italic,
fonts,
self.char_height,
));
}
/// Add a new collection of fonts for bold italic styled text. These fonts
/// will come _after_ previously provided fonts in the fallback order.
///
/// You do not have to provide these for bold text to be supported. If no
/// bold fonts are supplied, rendering will fallback to the italic fonts
/// with fake bolding.
pub fn add_bold_italic_fonts(&mut self, fonts: impl IntoIterator<Item = Font<'a>>) {
self.char_width = self.char_width.min(Self::add_fonts_internal(
&mut self.bold_italic,
fonts,
self.char_height,
));
}
}
impl<'a> Fonts<'a> {
/// The minimum width (in pixels) across all fonts.
pub(crate) fn min_width_px(&self) -> u32 {
self.char_width
}
pub(crate) fn count(&self) -> usize {
1 + self.bold.len() + self.italic.len() + self.bold_italic.len() + self.regular.len()
}
pub(crate) fn font_for_cell(&self, cell: &Cell) -> (&Font, bool, bool) {
if cell.modifier.contains(Modifier::BOLD | Modifier::ITALIC) {
self.select_font(
cell.symbol(),
self.bold_italic
.iter()
.map(|f| (f, false, false))
.chain(self.italic.iter().map(|f| (f, true, false)))
.chain(self.bold.iter().map(|f| (f, false, true)))
.chain(self.regular.iter().map(|f| (f, true, true))),
true,
true,
)
} else if cell.modifier.contains(Modifier::BOLD) {
self.select_font(
cell.symbol(),
self.bold
.iter()
.map(|f| (f, false, false))
.chain(self.regular.iter().map(|f| (f, true, false))),
true,
false,
)
} else if cell.modifier.contains(Modifier::ITALIC) {
self.select_font(
cell.symbol(),
self.italic
.iter()
.map(|f| (f, false, false))
.chain(self.regular.iter().map(|f| (f, false, true))),
false,
true,
)
} else {
self.select_font(
cell.symbol(),
self.regular.iter().map(|f| (f, false, false)),
false,
false,
)
}
}
fn select_font<'fonts>(
&'fonts self,
cluster: &str,
fonts: impl IntoIterator<Item = (&'fonts Font<'a>, bool, bool)>,
last_resort_fake_bold: bool,
last_resort_fake_italic: bool,
) -> (&'fonts Font<'a>, bool, bool) {
let mut max = 0;
let mut font = None;
for (candidate, fake_bold, fake_italic) in fonts.into_iter().chain(std::iter::once((
&self.last_resort,
last_resort_fake_bold,
last_resort_fake_italic,
))) {
let (count, last_idx) =
cluster
.chars()
.enumerate()
.fold((0, 0), |(mut count, _), (idx, ch)| {
count += usize::from(candidate.font().glyph_index(ch).is_some());
(count, idx)
});
if count > max {
max = count;
font = Some((candidate, fake_bold, fake_italic));
}
if count == last_idx + 1 {
break;
}
}
*font.get_or_insert((
&self.last_resort,
last_resort_fake_bold,
last_resort_fake_italic,
))
}
fn add_fonts_internal(
target: &mut Vec<Font<'a>>,
fonts: impl IntoIterator<Item = Font<'a>>,
char_height: u32,
) -> u32 {
let len = target.len();
target.extend(fonts);
target[len..]
.iter()
.map(|font| font.char_width(char_height))
.min()
.unwrap_or(u32::MAX)
}
}