Enum dvi::Var

pub enum Var {
    W = 0,
    X = 1,
    Y = 2,
    Z = 3,
}

A variable in DVI data.

DVI data has access to four variables. These variables are set using the Op::SetVar operation and used in the Op::Move operation.

These variables and associated operations exist to support the following optimization. It is possible to replace repeated identical Op::Right/Op::Down operations with sets and moves that serialize to a smaller number of bytes. For example this DVI sequence:

vec![
    dvi::Op::Down(300),
    dvi::Op::Down(300),
    dvi::Op::Down(300),
];

is identical to this DVI sequence:

vec![
    // Set Y to 300 and move down by that value.
    dvi::Op::SetVar(dvi::Var::Y, 300),
    // Move down by the current value of Y, 300.
    dvi::Op::Move(dvi::Var::Y),
    dvi::Op::Move(dvi::Var::Y),
];

The first sequence serializes to 9 bytes, while the second serializes to 5 bytes. This optimization is performed in TeX.2021.595 and onwards.

Of the four variables, Var::W and Var::X operate on the horizontal part of the cursor h, and Var::Y and Var::Z operate on the vertical part of the cursor v.

Variants

W = 0

X = 1

Y = 2

Z = 3

Trait Implementations

impl Clone for Var

fn clone(&self) -> Var

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Var

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

Formats the value using the given formatter.

impl PartialEq for Var

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl Copy for Var

impl Eq for Var

impl StructuralPartialEq for Var