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FontVerticalMetrics

Struct FontVerticalMetrics 

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pub struct FontVerticalMetrics {
    pub units_per_em: u16,
    pub ascender: i16,
    pub descender: i16,
    pub line_gap: i16,
}
Expand description

Font-wide vertical metrics needed to compute line height, in font design units.

This is a deliberately minimal, font-library-agnostic mirror of the ascender/descender/line-gap fields found in a font’s hhea/OS/2 tables. Higher layers (e.g. the oxitext facade) translate their font library’s richer metrics type into this struct so the layout engine stays free of any font-parser dependency.

Convert to pixels with value * (font_size_px / units_per_em).

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§units_per_em: u16

Design units per em (typically 1000 for CFF, 2048 for TrueType).

§ascender: i16

Typographic ascender in design units (positive, above baseline).

§descender: i16

Typographic descender in design units (negative, below baseline).

§line_gap: i16

Typographic line gap (extra leading between lines), in design units.

Implementations§

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impl FontVerticalMetrics

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pub fn ascent_px(&self, font_size_px: f32) -> f32

Returns the pixel ascent (always positive) at font_size_px.

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pub fn descent_px(&self, font_size_px: f32) -> f32

Returns the pixel descent depth (always positive) at font_size_px.

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pub fn line_gap_px(&self, font_size_px: f32) -> f32

Returns the pixel line gap at font_size_px.

Trait Implementations§

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impl Clone for FontVerticalMetrics

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fn clone(&self) -> FontVerticalMetrics

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

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

Performs copy-assignment from source. Read more
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impl Copy for FontVerticalMetrics

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impl Debug for FontVerticalMetrics

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl Eq for FontVerticalMetrics

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impl PartialEq for FontVerticalMetrics

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fn eq(&self, other: &FontVerticalMetrics) -> bool

Tests for self and other values to be equal, and is used by ==.
1.0.0 (const: unstable) · Source§

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl StructuralPartialEq for FontVerticalMetrics

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dest. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.