Struct ValueRecord 

pub struct ValueRecord<'a> {
    data: FontData<'a>,
    offset: u32,
    format: ValueFormat,
}

A GPOS ValueRecord, with fields read on demand.

The contents of a value record are described by a ValueFormat stored in the parent table, so a record cannot be located or interpreted on its own. This type stores the position of the record within its parent table’s data alongside that format, and reads individual fields only when they are asked for; constructing one performs no reads at all.

Fields

data: FontData<'a>

The offset data of the table containing the record.

offset: u32

The position of the record within data.

format: ValueFormat

Implementations

impl<'a> ValueRecord<'a>

pub fn new(data: FontData<'a>, offset: usize, format: ValueFormat) -> Self

Creates a value record positioned at offset within data.

data must be the offset data of the table containing the record, and not merely the bytes of the record itself: the device and variation index offsets in a value record are resolved relative to that table.

pub fn format(&self) -> ValueFormat

The format describing which fields this record contains.

pub fn byte_len(&self) -> usize

The number of bytes occupied by this record.

pub fn is_empty(&self) -> bool

Returns true if this record contains no fields.

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

The offset data of the table containing this record.

pub fn offset(&self) -> usize

The position of this record within offset_data.

pub fn x_placement(&self) -> Option<i16>

pub fn y_placement(&self) -> Option<i16>

pub fn x_advance(&self) -> Option<i16>

pub fn y_advance(&self) -> Option<i16>

pub fn x_placement_device( &self, ) -> Option<Result<DeviceOrVariationIndex<'a>, ReadError>>

pub fn y_placement_device( &self, ) -> Option<Result<DeviceOrVariationIndex<'a>, ReadError>>

pub fn x_advance_device( &self, ) -> Option<Result<DeviceOrVariationIndex<'a>, ReadError>>

pub fn y_advance_device( &self, ) -> Option<Result<DeviceOrVariationIndex<'a>, ReadError>>

pub fn device_offset(&self, field: ValueFormat) -> Option<Nullable<Offset16>>

Returns the raw, unresolved offset for the given device field.

The returned offset is relative to offset_data. Returns None if the field is not present in this record’s format, or if the record is truncated.

pub fn bytes(&self) -> Option<&'a [u8]>

The raw bytes of this record, or None if the data is truncated.

fn field_offset(&self, field: ValueFormat) -> Option<usize>

Returns the position of field within offset_data, or None if this record’s format doesn’t include it.

Fields are laid out in the order of their format bits and each occupies two bytes, so a field’s position is fixed by the number of lower format bits that are set.

fn read_i16(&self, field: ValueFormat) -> Option<i16>

fn read_device( &self, field: ValueFormat, ) -> Option<Result<DeviceOrVariationIndex<'a>, ReadError>>

Trait Implementations

impl<'a> Clone for ValueRecord<'a>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl ComputeSize for ValueRecord<'_>

fn compute_size(args: ValueFormat) -> Result<usize, ReadError>

Compute the number of bytes required to represent this type.

impl<'a> Copy for ValueRecord<'a>

impl Debug for ValueRecord<'_>

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

Formats the value using the given formatter.

impl<'a> Default for ValueRecord<'a>

fn default() -> ValueRecord<'a>

Returns the “default value” for a type.

impl Eq for ValueRecord<'_>

impl<'a> FontReadAt<'a> for ValueRecord<'a>

fn read_at( data: FontData<'a>, offset: usize, args: ValueFormat, ) -> Result<Self, ReadError>

Read an item positioned at offset bytes into data.

impl PartialEq for ValueRecord<'_>

Two records are equal when they describe the same positioning: same format, and the same bytes for the fields that format selects.

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

Equality operator ==.

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

Inequality operator !=.

impl ReadArgs for ValueRecord<'_>

type Args = ValueFormat