Struct PanZoomTransform 

pub struct PanZoomTransform {
    pub scale: f64,
    pub offset: Vec2,
}

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);

Where the content sits: view = offset + scale · content.

The child’s pod carries exactly affine; a content-space point (the child’s local coordinates) maps to the view’s local space through it and back through to_content.

Fields

scale: f64

The zoom factor: 1.0 is the child’s natural size.

offset: Vec2

Where the child’s local origin sits in the view, in view-local px.

Implementations

impl PanZoomTransform

pub const IDENTITY: PanZoomTransform

Unscaled, unpanned: the child at the view’s top-left at natural size.

pub fn affine(&self) -> Affine

The child pod’s transform: translate(offset) · scale(scale).

pub fn to_content(&self, point: Point) -> Point

The content-space point drawn at view-local point.

pub fn to_view(&self, point: Point) -> Point

Where content-space point is drawn, in view-local px.

Trait Implementations

impl Clone for PanZoomTransform

fn clone(&self) -> PanZoomTransform

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PanZoomTransform

impl Debug for PanZoomTransform

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

Formats the value using the given formatter.

impl Default for PanZoomTransform

fn default() -> PanZoomTransform

Returns the “default value” for a type.

impl PartialEq for PanZoomTransform

fn eq(&self, other: &PanZoomTransform) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for PanZoomTransform