Struct HintOptions

Source

pub struct HintOptions {
    engine: EngineRequest,
    target: RasterTarget,
    classic_cleartype: bool,
    symmetric_rendering: bool,
    preserve_linear_metrics: bool,
    pedantic: bool,
}

Expand description

Hinting configuration for a ScalerFont.

Create one with a constructor and adjust it with the with_* methods:

use skrifa::{HintOptions, RasterTarget};

let hinting = HintOptions::interpreter()
    .with_target(RasterTarget::Lcd)
    .with_classic_cleartype(true);
assert_eq!(hinting.target(), RasterTarget::Lcd);

Fields§

§engine: EngineRequest§target: RasterTarget§classic_cleartype: bool§symmetric_rendering: bool§preserve_linear_metrics: bool§pedantic: bool

Implementations§

Source §

impl HintOptions

Source

pub fn auto_fallback() -> Self

Creates a configuration that chooses the engine based on the font, with a grayscale target.

Uses the font’s own instructions when it has any, and the automatic hinter otherwise. A TrueType font with no glyph, font or control value program is autohinted.

Source

pub fn interpreter() -> Self

Creates a configuration that uses the instructions embedded in the font.

This runs the TrueType interpreter or the PostScript hinter, depending on which kind of instructions the font contains.

Source

pub fn auto() -> Self

Creates a configuration that uses the automatic hinter, which ignores the font’s instructions.

A TrueType font that needs its instructions to draw correct contours always runs the interpreter.

The data the hinter derives from a font is stored with the font. All scalers for that font share it at every size.

Source

fn with_engine(engine: EngineRequest) -> Self

Creates the defaults for a grayscale target that uses engine.

Source

pub fn with_target(self, target: RasterTarget) -> Self

Sets the rasterization target.

Source

pub fn with_classic_cleartype(self, classic_cleartype: bool) -> Self

Sets whether the TrueType interpreter uses the classic ClearType behavior.

By default, a version 1 gasp table selects symmetric smoothing and grid fitting per size, and glyphs that opt out of backward compatibility with INSTCTRL selector 3 keep fractional horizontal positions. With the classic behavior, every glyph is grid fitted, the symmetric rendering bit of GETINFO follows symmetric_rendering alone, and horizontal moves round to whole pixels. This is the behavior of HintingInstance. Defaults to off.

See https://github.com/googlefonts/fontations/issues/2112.

Source

pub fn with_symmetric_rendering(self, symmetric_rendering: bool) -> Self

Sets whether TrueType bytecode may assume vertical supersampling during rasterization.

This is the symmetric rendering bit of the GETINFO instruction. When it is set, ClearType fonts often generate wider horizontal stems that look blurry with an analytic area rasterizer. It is set by default. Unless classic ClearType is on, the font’s gasp table can also clear it per size. Only the TrueType interpreter reads it. See https://github.com/googlefonts/fontations/issues/1080.

Source

pub fn with_preserve_linear_metrics(self, preserve_linear_metrics: bool) -> Self

Sets whether hinting leaves the outline unchanged horizontally.

Hinting then moves points only vertically, so a glyph keeps its unhinted horizontal shape and spacing. The advance a draw reports is still rounded to a whole pixel, as for any hinted draw. The TrueType interpreter runs in backward compatibility mode, and the automatic hinter works as it does for a RasterTarget::Light target. Defaults to off.

Source