Struct Fonts

pub struct Fonts(/* private fields */);

The collection of fonts used by epaint.

Required in order to paint text. Create one and reuse. Cheap to clone.

Each Fonts comes with a font atlas textures that needs to be used when painting.

If you are using egui, use egui::Context::set_fonts and egui::Context::fonts.

You need to call Self::begin_frame and Self::font_image_delta once every frame.

Implementations

impl Fonts

pub fn new( pixels_per_point: f32, max_texture_side: usize, definitions: FontDefinitions, ) -> Fonts

Create a new Fonts for text layout. This call is expensive, so only create one Fonts and then reuse it.

• pixels_per_point: how many physical pixels per logical “point”.
• max_texture_side: largest supported texture size (one side).

pub fn begin_frame(&self, pixels_per_point: f32, max_texture_side: usize)

Call at the start of each frame with the latest known pixels_per_point and max_texture_side.

Call after painting the previous frame, but before using Fonts for the new frame.

This function will react to changes in pixels_per_point and max_texture_side, as well as notice when the font atlas is getting full, and handle that.

pub fn font_image_delta(&self) -> Option<ImageDelta>

Call at the end of each frame (before painting) to get the change to the font texture since last call.

pub fn pixels_per_point(&self) -> f32

pub fn max_texture_side(&self) -> usize

pub fn texture_atlas(&self) -> Arc<Mutex<TextureAtlas>>

The font atlas. Pass this to crate::Tessellator.

pub fn font_image_size(&self) -> [usize; 2]

Current size of the font image. Pass this to crate::Tessellator.

pub fn glyph_width(&self, font_id: &FontId, c: char) -> f32

Width of this character in points.

pub fn row_height(&self, font_id: &FontId) -> f32

Height of one row of text in points

pub fn families(&self) -> Vec<FontFamily>

List of all known font families.

pub fn layout_job(&self, job: LayoutJob) -> Arc<Galley>

Layout some text.

This is the most advanced layout function. See also Self::layout, Self::layout_no_wrap and Self::layout_delayed_color.

The implementation uses memoization so repeated calls are cheap.

pub fn num_galleys_in_cache(&self) -> usize

pub fn font_atlas_fill_ratio(&self) -> f32

How full is the font atlas?

This increases as new fonts and/or glyphs are used, but can also decrease in a call to Self::begin_frame.

pub fn layout( &self, text: String, font_id: FontId, color: Color32, wrap_width: f32, ) -> Arc<Galley>

Will wrap text at the given width and line break at \n.

The implementation uses memoization so repeated calls are cheap.

pub fn layout_no_wrap( &self, text: String, font_id: FontId, color: Color32, ) -> Arc<Galley>

Will line break at \n.

The implementation uses memoization so repeated calls are cheap.

pub fn layout_delayed_color( &self, text: String, font_id: FontId, wrap_width: f32, ) -> Arc<Galley>

Like Self::layout, made for when you want to pick a color for the text later.

The implementation uses memoization so repeated calls are cheap.