Crate alpha2_layout 

Where alpha2 text and layout boxes lie, without a GPU.

A text style or a layout generator’s box tree becomes the requests the text host (alpha2-text) draws and the rectangles they fill: text by its style’s position and anchor, a layout by CSS flexbox and grid. The engine draws from these same requests and rectangles, so a measurement and a frame place text alike, and a host without a GPU (a wasm page, the Python package) measures what a render would draw. json writes the measurements in the one JSON form every binding returns.

Re-exports

pub use layout::LAYOUT_WRAP_SLACK;

pub use layout::LayoutBounds;

pub use layout::NodeBounds;

pub use layout::NodeRects;

pub use layout::ResolvedLayout;

pub use layout::layout_texts;

pub use layout::measure_layout;

pub use layout::resolve;

pub use layout::shape_texts;

Modules

json

Measurements as JSON, from generators as a project holds them: the one form the wasm binding and the Python package return.

layout

Layout generators: box trees laid out by CSS flexbox and grid with the fonts the engine draws with.

Structs

Baselines

Where a text’s first and last lines’ alphabetic baselines lie, y as a fraction of the canvas (or picture) height, as a CanvasRect’s top is: a text’s baseline lines up with another’s, or with a point, by arithmetic.

CanvasRect

A rectangle as fractions of the canvas, y down.

FontFiles

The faces a host registers from a list of font files, and each file’s bytes (fonts_from_files).

PictureSize

The size, in pixels, of a picture text and layouts are placed on: never empty, and within the largest frame the engine draws (alpha2_media::MAX_FRAME_DIMENSION, alpha2_media::MAX_FRAME_PIXELS).

TextBounds

Where a text lies, as fractions of the canvas, (0, 0) top-left to (1, 1) bottom-right, as its style’s position is: on the picture a text generator draws, before its clip’s transform and effects, and on the canvas for a caption. measure_text measures it.

Enums

FontFileError

Why a font file could not be registered (fonts_from_files).

PictureSizeError

Why a size is not a PictureSize.

Constants

MAX_FONT_PIXELS

The largest font, outline, and padding the text host draws, in pixels.

MAX_OUTLINE_PIXELS

See MAX_FONT_PIXELS.

MAX_PADDING_PIXELS

See MAX_FONT_PIXELS.

Functions

fonts_from_files

The fonts of the files at paths, in fallback order, as a host registers them, and each file’s bytes, read once: each file’s family is its file stem, and every face of a collection is registered, in its order, sharing the file’s bytes, so its weights can be matched. A measurement and a render given the same paths draw with the same faces.

layout_text_key

A layout text’s raster request as a text store key: FNV-1a over a domain byte and every field of the request. Never zero.

measure_text

Where text in style lies on a canvas of size (TextBounds), laid out with rasterizer’s fonts as the engine’s text store lays it out and placed as a frame places it, without drawing it. Measured at the size a frame is drawn at, it agrees with that frame to the pixel; text laid out at another size can break its lines elsewhere.

rgba8

A straight, sRGB-encoded color as bytes.

shaped_key

What a request is shaped from, as a shaped-text cache key: equal keys shape alike with the same fonts.

text_key

A text’s identity at a render size: the text, its style, and the size, hashed (FNV-1a). Never zero.

text_request

The text host request for text in style on a picture of size, its content version key: sizes scaled from canvas fractions to pixels, within what the text host draws.