Struct glyph_brush::GlyphCalculator

pub struct GlyphCalculator<F = FontArc, X = Extra, H = DefaultSectionHasher> { /* fields omitted */ }

Cut down version of a GlyphBrush that can calculate pixel bounds, but is unable to actually render anything.

Build using a GlyphCalculatorBuilder.

Example

use glyph_brush::{ab_glyph::FontArc, GlyphCalculatorBuilder, GlyphCruncher, Section, Text};

let dejavu = FontArc::try_from_slice(include_bytes!("../../fonts/DejaVuSans.ttf")).unwrap();
let glyphs = GlyphCalculatorBuilder::using_font(dejavu).build();

let section = Section::default()
    .add_text(Text::new("Hello glyph_brush"));

// create the scope, equivalent to a lock on the cache when
// dropped will clean unused cached calculations like a draw call
let mut scope = glyphs.cache_scope();

let bounds = scope.glyph_bounds(section);

Caching behaviour

Calls to GlyphCalculatorGuard::glyph_bounds, GlyphCalculatorGuard::glyphs calculate the positioned glyphs for a section. This is cached so future calls to any of the methods for the same section are much cheaper.

Unlike a GlyphBrush there is no concept of actually drawing the section to imply when a section is used / no longer used. Instead a GlyphCalculatorGuard is created, that provides the calculation functionality. Dropping indicates the 'cache frame' is over, similar to when a GlyphBrush draws. Section calculations are cached for the next 'cache frame', if not used then they will be dropped.

Implementations

impl<F: Font, X, H: BuildHasher + Clone> GlyphCalculator<F, X, H>

pub fn cache_scope(&self) -> GlyphCalculatorGuard<'_, F, X, H>

pub fn fonts(&self) -> &[F]

Returns the available fonts.

The FontId corresponds to the index of the font data.

Trait Implementations

impl<F, X, H> Debug for GlyphCalculator<F, X, H>

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

Formats the value using the given formatter.