Crate denise 

Denise — a direct-rendering UI toolkit for systems without a desktop environment.

This crate is the platform-agnostic core. It owns geometry, colour, the pixel buffer contract, input events and damage tracking. It contains no platform code and no unsafe.

Backends implement two traits:

• Surface — hands out a Frame to draw into and presents damaged regions.
• InputSource — drains platform input into InputEvents.

Frame lifecycle

let mut frame = surface.acquire()?;
// The buffer we just got back may be several frames old. Repaint everything
// that has been damaged since it was last current, not just this frame's damage.
let damage: &[Rect] = tracker.resolve(frame.age());
// ... draw into `frame`, clipped to `damage` ...
drop(frame);
surface.present(damage)?;
tracker.end_frame();

Getting that sequence wrong is the classic double-buffering bug: repaint only the current frame’s damage and every second frame shows stale content.

Theming

Colours are named by role — Role::Primary, Role::Base100, Role::Error — each with a *Content partner. Theme::pair returns a surface and a foreground that are guaranteed to contrast, and Theme::validate proves it for a custom theme rather than leaving it to be discovered on a panel in daylight. The arithmetic is WCAG relative luminance in integers, so it is identical on x86 and ARM.

Status

M5 complete, M6 in progress. Everything through M5 has run on real hardware — a Raspberry Pi on DRM/KMS, Windows 11 on ARM64, macOS — not only in CI. See the README for the roadmap.

Re-exports

pub use color::Color;

pub use cursor::CursorPlane;

pub use damage::DamageTracker;

pub use damage::MAX_DAMAGE_RECTS;

pub use damage::RectList;

pub use geom::Point;

pub use geom::Rect;

pub use geom::Size;

pub use input::ElementState;

pub use input::InputEvent;

pub use input::InputSource;

pub use input::KeyCode;

pub use input::Modifiers;

pub use input::PointerButton;

pub use input::TouchId;

pub use surface::BufferAge;

pub use surface::Frame;

pub use surface::PixelFormat;

pub use surface::Surface;

pub use surface::SurfaceError;

pub use surface::required_words;

pub use theme::ColorScheme;

pub use theme::Metrics;

pub use theme::Radius;

pub use theme::Role;

pub use theme::Theme;

Modules

color

Straight (non-premultiplied) 8-bit-per-channel colour.

cursor

The hardware cursor plane, for backends that have one.

damage

Dirty-rectangle tracking.

geom

Integer geometry.

input

Backend-independent input events.

surface

The pixel buffer contract every backend implements.

theme

Semantic theming.