Struct MathKern 

pub struct MathKern<'a> {
    data: TableDataRef<'a, MathKernFixedHeader>,
}

MathKern

Fields

data: TableDataRef<'a, MathKernFixedHeader>

Implementations

impl<'a> MathKern<'a>

pub const MIN_SIZE: usize = u16::RAW_BYTE_LEN

pub fn resolve_offset<O: Offset, R: FontRead<'a, Args = ()>>( &self, offset: O, ) -> Result<R, ReadError>

Resolve the provided offset from the start of this table.

pub fn offset_data(&self) -> FontData<'a>

Return a reference to this table’s raw data.

We use this in the compile crate to resolve offsets.

pub fn shape(&self) -> &Self

👎Deprecated:

just use the base type directly

Return a reference to the table’s ‘Shape’ struct.

This is a low level implementation detail, but it can be useful in some cases where you want to know things about a table’s layout, such as the byte offsets of specific fields.

pub fn height_count(&self) -> u16

Number of heights at which the kern value changes.

pub fn correction_height(&self) -> &'a [MathValueRecord]

Array of correction heights, in design units, sorted from lowest to highest.

pub fn kern_values(&self) -> &'a [MathValueRecord]

Array of kerning values for different height ranges, in design units.

There is one more of these than there are correction heights: the first applies below the first correction height, and the last above the last.

pub fn height_count_byte_range(&self) -> Range<usize>

pub fn correction_height_byte_range(&self) -> Range<usize>

pub fn kern_values_byte_range(&self) -> Range<usize>

impl MathKern<'_>

pub fn kerning(&self, correction_height: i32) -> Option<i32>

The kern to apply at a height above the baseline, in design units.

The table divides the vertical range into bands, and this answers the value for the band correction_height falls in: the one whose lower bound is the last correction height at or below it. A height above every correction height takes the final value.

Correction heights are stored in ascending order and there are rarely more than a handful, so this walks them.

The heights are compared as the font stores them, without the device adjustments they may carry. Applying those would mean choosing a size and a coordinate space to compare in, which is the caller’s to choose: entries_for_ppem hands over the bands so it can.

pub fn entries_for_ppem( &self, ppem: u16, ) -> impl Iterator<Item = MathKernEntry> + '_

The upper bound and kern of each band, lowest first.

Every value comes as read at ppem, carrying its own adjustment.

This is what to pick a kern from when the adjustments matter. Which band a height falls in depends on the space the comparison happens in – design units, pixels, or a scaled position, the last of which also decides whether the vertical axis points up or down – and only the caller knows that.

fn band(&self, correction_height: i32) -> usize

The index of the band a height falls in.

Trait Implementations

impl<'a> Clone for MathKern<'a>

fn clone(&self) -> MathKern<'a>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for MathKern<'_>

fn default() -> Self

Returns the “default value” for a type.

impl<'a> FontRead<'a> for MathKern<'a>

fn read_with_args(data: FontData<'a>, _: ()) -> Result<Self, ReadError>

Read an item, performing validation.

fn read(data: FontData<'a>) -> Result<Self, ReadError>

where Self: FontRead<'a, Args = ()>,

Read an instance of Self from the provided data, performing validation.

impl<'a> MinByteRange<'a> for MathKern<'a>

fn min_byte_range(&self) -> Range<usize>

fn min_table_bytes(&self) -> &'a [u8]

impl ReadArgs for MathKern<'_>

type Args = ()