Struct DrawCtx 

pub struct DrawCtx { /* private fields */ }

What a crate::Custom node draws into. Coordinates are the node’s own: the origin is the node center, positive x is right, positive y is down.

The closure runs every time the frame is painted. It has to be a function of t, of signals it captured, and of DrawCtx::rng: the same inputs must produce the same shapes, because a frame can be painted more than once and a seek paints it without the frames in between.

Implementations

impl DrawCtx

pub fn time(&self) -> f64

Time of the frame being painted, in seconds.

pub fn size(&self) -> (f64, f64)

The node’s box, in its own coordinates.

pub fn quality(&self) -> f64

1 is a full frame. A later draft mode will pass a smaller value so a closure can draw fewer shapes; it does not change positions.

pub fn rng(&self, seed: u64) -> DrawRng

Generator for seed. It does not touch the scene’s random(), and the same seed is the same sequence on every paint of this frame.

pub fn line(&mut self, a: impl Into<Point>, b: impl Into<Point>) -> Pen<'_>

A straight segment from a to b.

pub fn circle(&mut self, center: impl Into<Point>, radius: f64) -> Pen<'_>

A filled or stroked circle.

pub fn rect(&mut self, rect: Rect) -> Pen<'_>

A rectangle in the node’s coordinates.

pub fn path(&mut self, path: BezPath) -> Pen<'_>

An arbitrary outline.

pub fn image(&mut self, rect: Rect, image: Rc<RasterImage>)

A picture stretched over rect, in the node’s coordinates. Draws with the node’s opacity, like the shapes.

pub fn arc( &mut self, center: impl Into<Point>, radius: f64, start: f64, sweep: f64, ) -> Pen<'_>

An arc of a circle around center, starting at start degrees (0 is to the right, clockwise like rotation) and turning sweep degrees. Stroke it for a gauge or a ring.