Struct Metrics 

pub struct Metrics<'a> {
    pub width: &'a dyn Fn(u32) -> i32,
    pub ascent: i32,
    pub descent: i32,
}

What the engine needs to know about the font it is setting.

A plain record rather than a trait: there is exactly one real implementation, and the test stub is a different set of numbers rather than a different behavior.

use pdfrum_doc::geom;
use pdfrum_doc::vt::{Config, Metrics, layout};

// Every character ten thousandths wide: the stub the layout assertions
// in this crate are written against.
let width = |_code: u32| 10;
let metrics = Metrics { width: &width, ascent: 1000, descent: -200 };

let config = Config {
    plate: geom::rect(0.0, 0.0, 100.0, 40.0),
    font_size: 10.0,
    multi_line: true,
    ..Config::default()
};
let laid_out = layout("Hi", &config, &metrics);

// Nothing here reads a font dictionary; the numbers are the whole
// contract between a caller and the engine.
assert_eq!(laid_out.font_size, 10.0);

Fields

width: &'a dyn Fn(u32) -> i32

Width per character, in thousandths of an em.

ascent: i32

The font’s ascent, in thousandths.

descent: i32

The font’s descent, in thousandths — normally negative.

Trait Implementations

impl<'a> Clone for Metrics<'a>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for Metrics<'a>

impl Debug for Metrics<'_>

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

Formats the value using the given formatter.