Trait ab_glyph::ScaleFont

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pub trait ScaleFont<F: Font> {
Show 20 methods    // Required methods
    fn scale(&self) -> PxScale;
    fn font(&self) -> &F;
    fn codepoint_ids(&self) -> CodepointIdIter<'_> ⓘ;

    // Provided methods
    fn h_scale_factor(&self) -> f32 { ... }
    fn v_scale_factor(&self) -> f32 { ... }
    fn scale_factor(&self) -> PxScaleFactor { ... }
    fn ascent(&self) -> f32 { ... }
    fn descent(&self) -> f32 { ... }
    fn height(&self) -> f32 { ... }
    fn line_gap(&self) -> f32 { ... }
    fn glyph_id(&self, c: char) -> GlyphId { ... }
    fn scaled_glyph(&self, c: char) -> Glyph { ... }
    fn h_advance(&self, id: GlyphId) -> f32 { ... }
    fn h_side_bearing(&self, id: GlyphId) -> f32 { ... }
    fn v_advance(&self, id: GlyphId) -> f32 { ... }
    fn v_side_bearing(&self, id: GlyphId) -> f32 { ... }
    fn kern(&self, first: GlyphId, second: GlyphId) -> f32 { ... }
    fn glyph_bounds(&self, glyph: &Glyph) -> Rect { ... }
    fn glyph_count(&self) -> usize { ... }
    fn outline_glyph(&self, glyph: Glyph) -> Option<OutlinedGlyph> { ... }
}

Expand description

A Font with an associated pixel scale. This can be used to provide pixel scale values for glyph advances, heights etc.

§Example

use ab_glyph::{Font, FontRef, PxScale, ScaleFont};

let font = FontRef::try_from_slice(include_bytes!("../../dev/fonts/Exo2-Light.otf"))?;

// Associate the font with a scale of 45px
let scaled_font = font.as_scaled(PxScale::from(45.0));

assert_eq!(scaled_font.height(), 45.0);
assert_eq!(scaled_font.h_advance(scaled_font.glyph_id('b')), 21.225);

// Replace associated scale with another
let scaled_font = scaled_font.with_scale(180.0);

assert_eq!(scaled_font.height(), 180.0);
assert_eq!(scaled_font.h_advance(scaled_font.glyph_id('b')), 84.9);

Required Methods§

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fn scale(&self) -> PxScale

Returns the pixel scale associated with this font.

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fn font(&self) -> &F

Returns a font reference.

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

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

Same as Font::codepoint_ids.

Provided Methods§

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fn h_scale_factor(&self) -> f32

Scale factor for unscaled font horizontal values.

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fn v_scale_factor(&self) -> f32

Scale factor for unscaled font vertical values.

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fn scale_factor(&self) -> PxScaleFactor

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fn ascent(&self) -> f32

Pixel scaled glyph ascent. See glyph layout concepts.

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fn descent(&self) -> f32

Pixel scaled glyph descent. See glyph layout concepts.

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fn height(&self) -> f32

Pixel scaled height ascent - descent. See glyph layout concepts.

By definition of PxScale, this is self.scale().y.

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fn line_gap(&self) -> f32

Pixel scaled line gap. See glyph layout concepts.

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

Lookup a GlyphId matching a given char.

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fn scaled_glyph(&self, c: char) -> Glyph

Construct a Glyph with the font’s pixel scale at position point(0.0, 0.0).

§Example

let scaled_font = font.as_scaled(50.0);

let a1 = scaled_font.scaled_glyph('a');
let a2 = font.glyph_id('a').with_scale(50.0); // equivalent

assert_eq!(a1.scale, PxScale::from(50.0));
assert_eq!(a1.position, point(0.0, 0.0));

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

Pixel scaled horizontal advance for a given glyph. See glyph layout concepts.

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

Pixel scaled horizontal side bearing for a given glyph. See glyph layout concepts.

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

Pixel scaled vertical advance for a given glyph.

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

Pixel scaled vertical side bearing for a given glyph.

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

Returns additional pixel scaled kerning to apply for a particular pair of glyphs.

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

Returns the layout bounds of this glyph.

Horizontally: Glyph position +/- h_advance/h_side_bearing. Vertically: Glyph position +/- ascent/descent.

These are not the same as OutlinedGlyph::px_bounds. If you are drawing pixels you should use px_bounds and not this method as outlines are not bound by layout values.

Note this method does not make use of the associated scale, as Glyph already includes one of it’s own.

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