Crate 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 bevy_sprite::text2d::update_text2d_layout system (in a 2d world space context) passes it into TextPipeline::update_text_layout_info, which:

1. updates a Buffer from the TextSpans, generating new FontAtlases 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.

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 the font atlases for a particular font in FontAtlasSet

FontAtlasSet

Set of rasterized fonts stored in FontAtlases.

FontFaceInfo

Information about a font collected as part of preparing for text layout.

FontFeatureTag

An OpenType font feature tag.

FontFeatures

OpenType features for .otf fonts that support them.

FontFeaturesBuilder

A builder for FontFeatures.

FontLoader

An AssetLoader for Fonts, for use by the AssetServer

FontWeight

How thick or bold the strokes of a font appear.

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.

RunGeometry

Geometry of a text run used to render text decorations like background colors, strikethrough, and underline. A run in bevy_text is a contiguous sequence of glyphs on a line that share the same text attributes like font, font size, and line height.

Strikethrough

A text entity with this component is drawn with strikethrough.

StrikethroughColor

Color for the text’s strikethrough. If this component is not present, its TextColor will be used.

SwashCache

A wrapper resource around a cosmic_text::SwashCache

Text2dUpdateSystems

System set in PostUpdate where all 2d text update systems are executed.

TextBackgroundColor

The background color of the text for this section.

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, the line height, and the antialiasing method.

TextIterScratch

Scratch buffer used to store intermediate state when iterating over text spans.

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 text in a tree of spans.

TextSpanIter

Iterator returned by TextReader::iter.

TextWriter

System parameter for reading and writing text spans in a text block.

Underline

Add to a text entity to draw its text with underline.

UnderlineColor

Color for the text’s underline. If this component is not present, its TextColor will be used.

Enums

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.

Justify

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.

LineHeight

Specifies the height of each line of text for Text and Text2d

TextError

Errors related to the textsystem

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

add_glyph_to_atlas

Adds the given subpixel-offset glyph to the given font atlases

detect_text_needs_rerender

System that detects changes to text blocks and sets ComputedTextBlock::should_rerender.

free_unused_font_atlases_system

A system that automatically frees unused texture atlases when a font asset is removed.

get_glyph_atlas_info

Generates the GlyphAtlasInfo for the given subpixel-offset glyph.

get_outlined_glyph_texture

Get the texture of the glyph as a rendered image, and its offset

load_font_to_fontdb

Add the font to the cosmic text’s FontSystem’s in-memory font database