Struct glyph_brush::GlyphBrush

pub struct GlyphBrush<'font, H = BuildHasherDefault<SeaHasher>> { /* private fields */ }

Object allowing glyph drawing, containing cache state. Manages glyph positioning cacheing, glyph draw caching & efficient GPU texture cache updating.

Build using a GlyphBrushBuilder.

Caching behaviour

Calls to GlyphBrush::queue, GlyphBrush::pixel_bounds, GlyphBrush::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. In the case of GlyphBrush::queue the calculations will also be used for actual drawing.

The cache for a section will be cleared after a GlyphBrush::process_queued call when that section has not been used since the previous call.

Implementations

impl<'font, H: BuildHasher> GlyphBrush<'font, H>

pub fn queue_custom_layout<'a, S, G>(&mut self, section: S, custom_layout: &G)where
    G: GlyphPositioner,
    S: Into<Cow<'a, VariedSection<'a>>>,

Queues a section/layout to be processed by the next call of process_queued. Can be called multiple times to queue multiple sections for drawing.

Used to provide custom GlyphPositioner logic, if using built-in Layout simply use queue

Benefits from caching, see caching behaviour.

pub fn queue<'a, S>(&mut self, section: S)where
    S: Into<Cow<'a, VariedSection<'a>>>,

Queues a section/layout to be processed by the next call of process_queued. Can be called multiple times to queue multiple sections for drawing.

Benefits from caching, see caching behaviour.

pub fn process_queued<V, F1, F2>(
    &mut self,
    (screen_w, screen_h): (u32, u32),
    update_texture: F1,
    to_vertex: F2
) -> Result<BrushAction<V>, BrushError>where
    F1: FnMut(Rect<u32>, &[u8]),
    F2: Fn(GlyphVertex) -> V,

Processes all queued sections, calling texture update logic when necessary & returning a BrushAction. See queue.

Trims the cache, see caching behaviour.

glyph_brush.process_queued(
    (1024, 768),
    |rect, tex_data| update_texture(rect, tex_data),
    |vertex_data| into_vertex(vertex_data),
)?

pub fn resize_texture(&mut self, new_width: u32, new_height: u32)

Rebuilds the texture cache with new dimensions. Should be avoided if possible.

Example

glyph_brush.resize_texture(512, 512);

pub fn texture_dimensions(&self) -> (u32, u32)

Returns the texture cache pixel dimensions (width, height).

pub fn fonts(&self) -> &[Font<'font>]

Returns the available fonts.

The FontId corresponds to the index of the font data.

pub fn add_font_bytes<'a: 'font, B: Into<SharedBytes<'a>>>(
    &mut self,
    font_data: B
) -> FontId

Adds an additional font to the one(s) initially added on build.

Returns a new FontId to reference this font.

Example

extern crate glyph_brush;
use glyph_brush::{GlyphBrushBuilder, Section};

// dejavu is built as default `FontId(0)`
let dejavu: &[u8] = include_bytes!("../../fonts/DejaVuSans.ttf");
let mut glyph_brush = GlyphBrushBuilder::using_font_bytes(dejavu).build();

// some time later, add another font referenced by a new `FontId`
let open_sans_italic: &[u8] = include_bytes!("../../fonts/OpenSans-Italic.ttf");
let open_sans_italic_id = glyph_brush.add_font_bytes(open_sans_italic);

pub fn add_font<'a: 'font>(&mut self, font_data: Font<'a>) -> FontId

Adds an additional font to the one(s) initially added on build.

Returns a new FontId to reference this font.

pub fn keep_cached_custom_layout<'a, S, G>(
    &mut self,
    section: S,
    custom_layout: &G
)where
    S: Into<Cow<'a, VariedSection<'a>>>,
    G: GlyphPositioner,

Retains the section in the cache as if it had been used in the last draw-frame.

Should not generally be necessary, see caching behaviour.

pub fn keep_cached<'a, S>(&mut self, section: S)where
    S: Into<Cow<'a, VariedSection<'a>>>,

Retains the section in the cache as if it had been used in the last draw-frame.

Should not generally be necessary, see caching behaviour.

Trait Implementations

impl<H> Debug for GlyphBrush<'_, H>

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

Formats the value using the given formatter.

impl<'font, H: BuildHasher> GlyphCruncher<'font> for GlyphBrush<'font, H>

fn pixel_bounds_custom_layout<'a, S, L>(
    &mut self,
    section: S,
    custom_layout: &L
) -> Option<Rect<i32>>where
    L: GlyphPositioner + Hash,
    S: Into<Cow<'a, VariedSection<'a>>>,

Returns the pixel bounding box for the input section using a custom layout. The box is a conservative whole number pixel rectangle that can contain the section.

fn glyphs_custom_layout<'a, 'b, S, L>(
    &'b mut self,
    section: S,
    custom_layout: &L
) -> PositionedGlyphIter<'b, 'font>where
    L: GlyphPositioner + Hash,
    S: Into<Cow<'a, VariedSection<'a>>>,

Returns an iterator over the PositionedGlyphs of the given section with a custom layout.

fn pixel_bounds<'a, S>(&mut self, section: S) -> Option<Rect<i32>>where
    S: Into<Cow<'a, VariedSection<'a>>>,

Returns the pixel bounding box for the input section. The box is a conservative whole number pixel rectangle that can contain the section.

fn glyphs<'a, 'b, S>(&'b mut self, section: S) -> PositionedGlyphIter<'b, 'font>where
    S: Into<Cow<'a, VariedSection<'a>>>,

Returns an iterator over the PositionedGlyphs of the given section.