Struct PanZoomController 

pub struct PanZoomController { /* private fields */ }

A pan/zoom viewport over one child — a node-and-edge graph, a map, a large image — without hand-rolling the gesture math. pan_zoom lays its child out at its natural size and places it under a scale-then-translate transform (PanZoomTransform) the user drives: primary drag pans (unless the child claims the press), a touch pinch or a desktop ctrl/⌘+wheel and trackpad pinch zooms about the gesture’s focal point, clamped to .min_scale/.max_scale. A plain wheel still reaches the child, and the child sees its own unscaled local coordinates at any zoom. Flat-re-exported from frust-widgets so app code never names that crate directly; see PanZoomView’s own doc for the full contract (.inertia glide, .on_transform notification, and the PanZoomController handle’s jump_to/fit_to_bounds/fit_rect).

use frust::authoring::{PaintCtx, PaintScene};
use frust::{AnyView, Component, PanZoomController, PanZoomTransform, any, canvas, pan_zoom};
use kurbo::{Point, Size};
use peniko::Color;

#[derive(Default)]
struct Board;

struct BoardState {
    zoom: PanZoomController,
    transform: PanZoomTransform,
}

impl Component for Board {
    type State = BoardState;

    fn init(&self) -> Self::State {
        BoardState {
            zoom: PanZoomController::new(),
            transform: PanZoomTransform::IDENTITY,
        }
    }

    fn build(&self, state: &mut Self::State) -> AnyView<Self::State> {
        let board = canvas(|scene: &mut dyn PaintScene, size: Size, _ctx: &PaintCtx| {
            scene.fill_rect(Point::ZERO, size, Color::from_rgb8(0x20, 0x20, 0x20));
        })
        .size(Size::new(2000.0, 1500.0));
        any(pan_zoom(board)
            .max_scale(4.0)
            .inertia(true)
            .controller(state.zoom.clone())
            .on_transform(|state: &mut BoardState, t| state.transform = t))
    }
}

frust::app!(Board);

A cloneable handle onto a PanZoomView: drive it with jump_to/fit_to_bounds/ fit_rect and read where it stands with transform. Every clone shares one state, so the handle an app keeps in its state and the one attached to the view are the same.

Commands are recorded, not applied: the widget applies the latest one at its next layout or paint (a later command replaces an unapplied earlier one), clamping the scale to the view’s bounds. One controller drives one view; attaching it to two makes them race for its commands.

Implementations

impl PanZoomController

pub fn new() -> PanZoomController

A controller attached to nothing yet, reading PanZoomTransform::IDENTITY.

pub fn transform(&self) -> PanZoomTransform

The transform the attached widget last published (identity until one attaches and lays out).

pub fn viewport_size(&self) -> Size

The attached widget’s last laid-out size (zero until it lays out).

pub fn content_size(&self) -> Size

The child’s last laid-out natural size (zero until it lays out).

pub fn jump_to(&self, scale: f64, offset: Vec2)

Move to scale (clamped to the view’s bounds) with the child’s origin at view-local offset.

pub fn fit_to_bounds(&self)

Fit the child’s whole laid-out bounds into the view, centred, at the largest scale that shows all of it (clamped to the view’s bounds).

pub fn fit_rect(&self, rect: Rect)

Fit rect, in the child’s content space, into the view, centred, at the largest scale that shows all of it (clamped to the view’s bounds).

Trait Implementations

impl Clone for PanZoomController

fn clone(&self) -> PanZoomController

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PanZoomController

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for PanZoomController

fn default() -> PanZoomController

Returns the “default value” for a type.