Struct KernedFont 

pub struct KernedFont { /* private fields */ }

A face paired with the pair kerning ab_glyph cannot read for itself, and with the single glyph substitutions of the OpenType features a text style enables.

This is a Font rather than a lookup the call sites reach for, because there are nine of them across measuring, line breaking, alignment and drawing, several behind impl Font generics that never see a SoftwareTextFont. Overriding kern_unscaled puts the rule under every existing scaled_font.kern(..) at once — including any this change did not go looking for — and keeps a caller from having to remember which width is the kerned one. Overriding glyph_id does the same for substitution: every glyph a run measures, kerns and draws is the substituted one.

Substitution covers GSUB single substitutions only (lookup type 1, and type 7 extensions of it), which is what tnum, pnum, onum, lnum, zero, smcp, c2sc, case, sups, subs, salt and ss01–ss20 use. A feature with any other lookup type (ligature, multiple, alternate, contextual) is not applied at all, so none is ever half applied, and no feature is on unless the style’s font_feature_settings turns it on.

Implementations

impl KernedFont

pub fn new(font: FontArc, kerning: Option<Arc<GposKerning>>) -> Self

pub fn read_kerning( bytes: &[u8], variations: &[([u8; 4], f32)], ) -> Option<Arc<GposKerning>>

Reads the GPOS pair kerning for a face instanced at variations.

variations are the (tag, user value) pairs actually applied to the face, in the same units the caller handed set_variation; normalizing them is ttf_parser’s job and doing it a second way here would be a second answer.

Trait Implementations

impl Clone for KernedFont

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Font for KernedFont

fn units_per_em(&self) -> Option<f32>

Get the size of the font unit

fn ascent_unscaled(&self) -> f32

Unscaled glyph ascent. See glyph layout concepts.

fn descent_unscaled(&self) -> f32

Unscaled glyph descent. See glyph layout concepts.

fn line_gap_unscaled(&self) -> f32

Unscaled line gap. See glyph layout concepts.

fn italic_angle(&self) -> f32

The slant angle of the font.

fn glyph_id(&self, c: char) -> GlyphId

Lookup a GlyphId matching a given char.

fn h_advance_unscaled(&self, id: GlyphId) -> f32

Unscaled horizontal advance for a given glyph id. See glyph layout concepts.

fn h_side_bearing_unscaled(&self, id: GlyphId) -> f32

Unscaled horizontal side bearing for a given glyph id. See glyph layout concepts.

fn v_advance_unscaled(&self, id: GlyphId) -> f32

Unscaled vertical advance for a given glyph id.

fn v_side_bearing_unscaled(&self, id: GlyphId) -> f32

Unscaled vertical side bearing for a given glyph id.

fn kern_unscaled(&self, first: GlyphId, second: GlyphId) -> f32

Returns additional unscaled kerning to apply for a particular pair of glyph ids.

fn outline(&self, id: GlyphId) -> Option<Outline>

Compute unscaled glyph outline curves & bounding box.

fn glyph_count(&self) -> usize

The number of glyphs present in this font. Glyph identifiers for this font will always be in the range 0..self.glyph_count()

fn codepoint_ids(&self) -> CodepointIdIter<'_>

Returns an iterator of all distinct (GlyphId, char) pairs. Not ordered.

fn glyph_raster_image2( &self, id: GlyphId, pixel_size: u16, ) -> Option<GlyphImage<'_>>

Returns a pre-rendered image of the glyph.

fn glyph_svg_image(&self, id: GlyphId) -> Option<GlyphSvg<'_>>

Returns raw SVG data of a range of glyphs which includes this one.

fn font_data(&self) -> &[u8]

Extracts a slice containing the data passed into e.g. FontArc::try_from_slice.

fn pt_to_px_scale(&self, pt_size: f32) -> Option<PxScale>

Converts pt units into PxScale.

fn height_unscaled(&self) -> f32

Unscaled height ascent - descent. See glyph layout concepts.

fn glyph_raster_image( &self, id: GlyphId, pixel_size: u16, ) -> Option<GlyphImage<'_>>

👎Deprecated since 0.2.22:

Deprecated in favor of glyph_raster_image2

Returns a pre-rendered image of the glyph.

fn glyph_bounds(&self, glyph: &Glyph) -> Rect

where Self: Sized,

Returns the layout bounds of this glyph.

fn outline_glyph(&self, glyph: Glyph) -> Option<OutlinedGlyph>

where Self: Sized,

Compute glyph outline ready for drawing.

fn as_scaled<S>(&self, scale: S) -> PxScaleFont<&Self>

where S: Into<PxScale>, Self: Sized,

Construct a PxScaleFont by associating with the given pixel scale.

fn into_scaled<S>(self, scale: S) -> PxScaleFont<Self>

where S: Into<PxScale>, Self: Sized,

Move into a PxScaleFont associated with the given pixel scale.