Crate fluor 

Fluor — first-principles GUI compositor library.

Named for fluorite (the mineral that gave us “fluorescence” — glows on a band nothing else occupies) and fluere (Latin: to flow — “liquid stone”). Hard substrate of pane geometry + chrome shared across consumers, fluid center-origin coordinates that scale with the viewport.

Every mainstream layout system is pixel-anchored: Android dp, CSS px, WPF DIPs, iOS pt, Flutter dp — all scale factors on a fixed physical reference. Even CSS vmin (the closest “viewport-relative” unit) uses min(w, h) and inherits a discontinuity at the diagonal. Fluor uses harmonic-mean span 2wh/(w+h) as its scaling base, with the origin at the viewport center and +y down. That combination — center-origin + harmonic-mean unit + default convention (not opt-in) — appears to be unoccupied territory among compositors and toolkits.

Built to deduplicate the chrome / paint / pane code currently duplicated across photon, rhe, and mandelbrot-exploder, and to be the eventual compositor for ferros.

Re-exports

pub use coord::Coord;

pub use coord::RuVec2;

pub use geom::Viewport;

pub use group::Group;

pub use paint::BlendMode;

pub use pane::Compositor;

pub use pane::Pane;

pub use pane::PaneId;

pub use pixel::Argb8;

pub use region::Region;

Modules

canvas

Drawing surface that bundles a pixel buffer with automatic damage tracking. Every public rasterizer takes a &mut Canvas instead of a bare &mut [u32] + width + height triple; rasterizers report the pixel rectangle they touched into the canvas’s Damage accumulator. Damage is unforgettable because it’s part of what you draw on, not a side parameter — consumer widgets get differential-redraw support automatically.

coord

Center-origin, +y-down 2D coordinates in f32.

event

Platform-neutral event vocabulary.

geom

Viewport geometry: pixel dimensions, derived universal scaling units, and conversions between RU coordinates and integer pixel coordinates.

group

Group — the unit of hit-routable, text-clippable composite.

host

Host backends — adapters between fluor’s Compositor and the platform’s window/framebuffer system.

paint

Pixel-buffer paint primitives. Packed layout is 0xααRRGGBB (α-byte high, blue low) — top byte is α (opacity), industry-standard direction (α = 0 transparent, α = 0xFF opaque). RGB bytes store darkness (0 = white, 255 = black). See crate::pixel for the locked convention. All inputs are pixel-space, not RU — convert via Viewport::ru_to_px before calling.

pane

Panes — the unit of UI in fluor — and the Compositor that owns them.

pixel

Pixel format + blend trait.

region

Proportional layout primitive — unidirectional nesting, no solver.

stack

Stack Notation compositing engine — layers as operands, blend ops as operators.

text

Text rendering — verbatim port of photon’s text_rasterizing.rs. Built on cosmic-text + swash. Bundles Open Sans Regular + Bold (OFL-licensed) so the default fluor build renders text out of the box; consumers can load additional fonts via the font_system_mut() accessor.

theme

Theme constants — colours and geometry shared between paint primitives, chrome, and (eventually) widgets. Sourced from photon’s theme.rs; names match photon exactly so cross-codebase greps work.

widgets

Widget primitives — single-line textbox today, more to come (button, scroll, etc.). Each widget owns its visual + interaction state and renders into a pixel buffer via the shared paint + text infrastructure.