geometry

2D geometry in f64: Point, Rect and the affine Matrix, in the layout of CSS and SVG matrix(a b c d e f).

Enough to map between coordinate spaces: build and multiply transforms, invert one to bring a point back, take the bounding box of a transformed rectangle (hit areas, gradient bounds), place content in a container like CSS object-fit (fit), simplify a polyline, and work with SVG path data: parse it (parse_path), transform it by a matrix (transform_path) and write rectangles and ellipses as paths (rounded_rect_path, ellipse_path).

Install

Cargo feature geometry (enabled by default). To compile only this module:

cargo add helpers4 --no-default-features --features geometry

or in Cargo.toml:

[dependencies]
helpers4 = { version = "0.0.11", default-features = false, features = ["geometry"] }

Import path: helpers4::geometry.

Items

Item	What it does
ellipse_path	The path of the ellipse that fills a box, as SVG path data: two half-turn arcs.
FitAlign	Where fit places content in the space left over (or overflowing), as CSS object-position: 0.0 is left or top, 0.5 centered, 1.0 right or bottom.
FitMode	How fit sizes content in a container, as CSS object-fit.
fit	Places content in a container like CSS object-fit and object-position, e.g.
format_path	Writes path commands back as SVG path data: letters glued to their first number, single spaces elsewhere, numbers rounded to precision decimals with the trailing zeros dropped (-0 is written 0).
Matrix	A 2D affine transformation (a 2×3 matrix), in the layout of CSS and SVG matrix(a, b, c, d, e, f):
parse_path	Parses SVG path data (the d attribute) into commands, as written: the letters keep their case (absolute or relative), H/V/S/T/A stay what they are, and a command repeated without its letter (L 1 2 3 4) becomes one command per set of numbers (M repeats as L, m as l).
PathCommand	One command of SVG path data: its letter (uppercase is absolute, lowercase relative to the current point) and its numbers, as written in the d attribute.
Point	A point in 2D space.
Rect	An axis-aligned rectangle: its top-left corner and its size.
rounded_rect_path	The path of a rectangle with a radius per corner, as SVG path data.
simplify_polyline	Removes the points of a polyline that change its shape by less than tolerance, with the Ramer–Douglas–Peucker algorithm: each removed point is at most tolerance away from the simplified line.
Size	A width and a height.
transform_path	Transforms SVG path data by a matrix.

Error types

Documented on the page of the helper that returns them.

Type	Returned by
ParsePathError	parse_path, transform_path