Crate bevy_text

This crate provides the tools for positioning and rendering text in Bevy.

Font

Fonts contain information for drawing glyphs, which are shapes that typically represent a single character, but in some cases part of a “character” (grapheme clusters) or more than one character (ligatures).

A font face is part of a font family, and is distinguished by its style (e.g. italic), its weight (e.g. bold) and its stretch (e.g. condensed).

In Bevy, Fonts are loaded by the FontLoader as assets.

TextPipeline

The TextPipeline resource does all of the heavy lifting for rendering text.

UI Text is first measured by creating a TextMeasureInfo in TextPipeline::create_text_measure, which is called by the measure_text_system system of bevy_ui.

Note that text measurement is only relevant in a UI context.

With the actual text bounds defined, the bevy_ui::widget::text::text_system system (in a UI context) or text2d::update_text2d_layout system (in a 2d world space context) passes it into TextPipeline::queue_text, which:

1. updates a Buffer from the TextSpans, generating new FontAtlasSets if necessary.
2. iterates over each glyph in the Buffer to create a PositionedGlyph, retrieving glyphs from the cache, or rasterizing to a FontAtlas if necessary.
3. PositionedGlyphs are stored in a TextLayoutInfo, which contains all the information that downstream systems need for rendering.

Re-exports

• pub use cosmic_text;

Modules

• prelude
  The text prelude.

Structs

• ComputedTextBlock
  Computed information for a text block.
• CosmicBuffer
  Wrapper for cosmic_text::Buffer
• CosmicFontSystem
  A wrapper resource around a cosmic_text::FontSystem
• Font
  An Asset that contains the data for a loaded font, if loaded as an asset.
• FontAtlas
  Rasterized glyphs are cached, stored in, and retrieved from, a FontAtlas.
• FontAtlasKey
  Identifies a font size and smoothing method in a FontAtlasSet.
• FontAtlasSet
  A map of font sizes to their corresponding FontAtlases, for a given font face.
• FontAtlasSets
  A map of font faces to their corresponding FontAtlasSets.
• FontLoader
  An AssetLoader for Fonts, for use by the AssetServer
• FontWeight
  Specifies the weight of glyphs in the font, their degree of blackness or stroke thickness.
• GlyphAtlasInfo
  Information about a glyph in an atlas.
• GlyphAtlasLocation
  The location of a glyph in an atlas, and how it should be positioned when placed.
• PositionedGlyph
  A glyph of a font, typically representing a single character, positioned in screen space.
• SwashCache
  A wrapper resource around a cosmic_text::SwashCache
• Text2d
  The top-level 2D text component.
• Text2dBundleDeprecated
  Text2dBundle was removed in favor of required components. The core component is now Text2d which can contain a single text segment. Indexed access to segments can be done with the new Text2dReader and Text2dWriter system params. Additional segments can be added through children with TextSpan. Text configuration can be done with TextLayout, TextFont and TextColor, while sprite-related configuration uses TextBounds and Anchor components.
• TextBounds
  The maximum width and height of text. The text will wrap according to the specified size.
• TextColor
  The color of the text for this section.
• TextEntity
  A sub-entity of a ComputedTextBlock.
• TextFont
  TextFont determines the style of a text span within a ComputedTextBlock, specifically the font face, the font size, and the color.
• TextLayout
  Component with text format settings for a block of text.
• TextLayoutInfo
  Render information for a corresponding text block.
• TextMeasureInfo
  Size information for a corresponding ComputedTextBlock component.
• TextPipeline
  The TextPipeline is used to layout and render text blocks (see Text/Text2d).
• TextPlugin
  Adds text rendering support to an app.
• TextReader
  System parameter for reading text spans in a text block.
• TextSpan
  A span of UI text in a tree of spans under an entity with TextLayout and Text or Text2d.
• TextSpanIter
  Iterator returned by TextReader::iter.
• TextWriter
  System parameter for reading and writing text spans in a text block.
• Update2dText
  System set in PostUpdate where all 2d text update systems are executed.

Enums

• FontFamily
  An owned version of Family
• FontLoaderError
  Possible errors that can be produced by FontLoader
• FontSmoothing
  Determines which antialiasing method to use when rendering text. By default, text is rendered with grayscale antialiasing, but this can be changed to achieve a pixelated look.
• FontStretch
  A face width.
• FontStyle
  Allows italic or oblique faces to be selected.
• JustifyText
  Describes the horizontal alignment of multiple lines of text relative to each other.
• LineBreak
  Determines how lines will be broken when preventing text from running out of bounds.
• TextError
  Errors related to the textsystem
• YAxisOrientation
  Text is rendered for two different view projections; 2-dimensional text (Text2d) is rendered in “world space” with a BottomToTop Y-axis, while UI is rendered with a TopToBottom Y-axis. This matters for text because the glyph positioning is different in either layout. For TopToBottom, 0 is the top of the text, while for BottomToTop 0 is the bottom.

Constants

• DEFAULT_FONT_DATA
  The raw data for the default font used by bevy_text

Traits

• TextRoot
  Helper trait for the root text component in a text block.
• TextSpanAccess
  Helper trait for using the TextReader and TextWriter system params.
• TextSpanComponent
  Helper trait for the text span components in a text block.

Functions

• calculate_bounds_text2d
  System calculating and inserting an Aabb component to entities with some TextLayoutInfo and Anchor components, and without a NoFrustumCulling component.
• detect_text_needs_rerender
  System that detects changes to text blocks and sets ComputedTextBlock::should_rerender.
• extract_text2d_sprite
  This system extracts the sprites from the 2D text components and adds them to the “render world”.
• remove_dropped_font_atlas_sets
  A system that cleans up FontAtlasSets for removed Fonts
• scale_value
  Scales value by factor.
• update_text2d_layout
  Updates the layout and size information whenever the text or style is changed. This information is computed by the TextPipeline on insertion, then stored.

Type Aliases

• Text2dReader
  2d alias for TextReader.
• Text2dWriter
  2d alias for TextWriter.