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//! Runtime autohinting support.
mod hint;
mod instance;
mod metrics;
mod outline;
mod recorder;
mod shape;
mod style;
mod topo;
pub use instance::GlyphStyles;
pub(crate) use instance::Instance;
pub use metrics::{
BlueZones, Scale, ScaleFlags, ScaledAxisMetrics, ScaledBlue, ScaledStyleMetrics, ScaledWidth,
UnscaledAxisMetrics, UnscaledBlue, UnscaledStyleMetrics, WidthMetrics,
};
pub use outline::Direction;
pub use recorder::{EdgeAction, EdgeHint, HintAction, PointAction, PointHint};
pub use style::{GlyphStyle, ScriptClass, ScriptGroup, StyleClass};
pub use style::{SCRIPT_CLASSES, STYLE_CLASSES};
pub use topo::{Axis, BlueProvenance, Dimension, Edge, Segment, TopoFlags};
use crate::outline::{DrawError, Target};
use crate::{FontRef, MetadataProvider};
use alloc::vec::Vec;
use raw::types::{F2Dot14, GlyphId};
/// Controls quirks for the different autohinters.
#[derive(Copy, Clone, PartialEq, Eq, Default, Debug)]
enum QuirksMode {
/// Just in time hinter; matches FreeType.
#[default]
Jit,
/// Ahead of time hinter; matches ttfautohint.
Aot,
}
/// Plan for hinting an outline.
#[derive(Clone, Debug, Default)]
pub struct HintPlan {
hints: Vec<HintAction>,
axes: [Option<Axis>; 2],
}
impl HintPlan {
/// Creates a new hint plan.
pub fn new(
font: &FontRef,
coords: &[F2Dot14],
ppem: f32,
target: Target,
glyph_id: GlyphId,
glyph_style: GlyphStyle,
) -> Result<Self, DrawError> {
let style_class = glyph_style
.style_class()
.ok_or(DrawError::GlyphNotFound(glyph_id))?;
let outline_glyph = font
.outline_glyphs()
.get(glyph_id)
.ok_or(DrawError::GlyphNotFound(glyph_id))?;
let shaper_mode = if cfg!(feature = "autohint_shaping") {
shape::ShaperMode::BestEffort
} else {
shape::ShaperMode::Nominal
};
let shaper = shape::Shaper::new(font, shaper_mode);
let metrics =
metrics::compute_unscaled_style_metrics(&shaper, coords, style_class, QuirksMode::Aot);
let mut outline = outline::Outline::default();
outline.fill(&outline_glyph, coords, QuirksMode::Aot)?;
let scale = metrics::Scale::new(
ppem,
outline_glyph.units_per_em() as i32,
font.attributes().style,
target,
metrics.style_class().script.group,
);
let mut recorder = recorder::HintsRecorder::default();
let hinted_plan = hint::hint_outline_with_recorder(
&mut outline,
&metrics,
&scale,
Some(glyph_style),
&mut recorder,
);
Ok(Self {
hints: recorder.actions,
axes: hinted_plan.axes,
})
}
/// Returns the collection of hinting actions.
pub fn actions(&self) -> &[HintAction] {
&self.hints
}
/// Returns the topological analysis of the horizontal axis.
pub fn horizontal_axis(&self) -> Option<&Axis> {
self.axes[Dimension::Horizontal].as_ref()
}
/// Returns the topological analysis of the vertical axis.
pub fn vertical_axis(&self) -> Option<&Axis> {
self.axes[Dimension::Vertical].as_ref()
}
}
/// All constants are defined based on a UPEM of 2048.
///
fn derived_constant(units_per_em: i32, value: i32) -> i32 {
value * units_per_em / 2048
}