Trait FontFuncs 

pub trait FontFuncs {
    // Provided methods
    fn nominal_glyph(
        &mut self,
        builtin: &BuiltinFontFuncs<'_>,
        c: u32,
    ) -> Option<GlyphId> { ... }
    fn variant_glyph(
        &mut self,
        builtin: &BuiltinFontFuncs<'_>,
        c: u32,
        vs: u32,
    ) -> Option<GlyphId> { ... }
    fn advance_width(
        &mut self,
        builtin: &BuiltinFontFuncs<'_>,
        glyph: GlyphId,
    ) -> i32 { ... }
    fn populate_advance_widths(
        &mut self,
        builtin: &BuiltinFontFuncs<'_>,
        batch: AdvanceWidthBatch<'_>,
    ) { ... }
    fn advance_height(
        &mut self,
        builtin: &BuiltinFontFuncs<'_>,
        glyph: GlyphId,
    ) -> i32 { ... }
    fn vertical_origin(
        &mut self,
        builtin: &BuiltinFontFuncs<'_>,
        glyph: GlyphId,
    ) -> (i32, i32) { ... }
    fn extents(
        &mut self,
        builtin: &BuiltinFontFuncs<'_>,
        glyph: GlyphId,
    ) -> Option<GlyphExtents> { ... }
}

Customizable font callback surface.

Metrics scaling

All font metrics returned by these callbacks must be consistent with the scale factor configured via ShapeOptions::scale.

If no scale is set, values must be in unscaled font units (i.e. the same coordinate space as the font’s units_per_em). If a scale is set — for example font_size * 64 for FreeType-style 26.6 — then all returned values must already be in that scaled coordinate space.

Provided Methods

fn nominal_glyph( &mut self, builtin: &BuiltinFontFuncs<'_>, c: u32, ) -> Option<GlyphId>

Nominal character-to-glyph mapping callback.

fn variant_glyph( &mut self, builtin: &BuiltinFontFuncs<'_>, c: u32, vs: u32, ) -> Option<GlyphId>

Variation-selector mapping callback.

fn advance_width( &mut self, builtin: &BuiltinFontFuncs<'_>, glyph: GlyphId, ) -> i32

Horizontal advance callback.

See “Metrics scaling” in the trait-level docs for details on what value this method should return.

fn populate_advance_widths( &mut self, builtin: &BuiltinFontFuncs<'_>, batch: AdvanceWidthBatch<'_>, )

Batch horizontal-advance callback.

See “Metrics scaling” in the trait-level docs for details on what value this method should return.

fn advance_height( &mut self, builtin: &BuiltinFontFuncs<'_>, glyph: GlyphId, ) -> i32

Vertical advance callback.

See “Metrics scaling” in the trait-level docs for details on what value this method should return.

fn vertical_origin( &mut self, builtin: &BuiltinFontFuncs<'_>, glyph: GlyphId, ) -> (i32, i32)

Vertical origin callback.

Returns the (x, y) coordinates of the vertical origin for the given glyph.

See “Metrics scaling” in the trait-level docs for details on what values this method should return.

fn extents( &mut self, builtin: &BuiltinFontFuncs<'_>, glyph: GlyphId, ) -> Option<GlyphExtents>

Glyph extents callback.

See “Metrics scaling” in the trait-level docs for details on what values this method should return.

Implementors