Struct TextItem 

pub struct TextItem { /* private fields */ }

Text in a local-coord rectangle, with optional alignment and rotation.

Text wraps within the local_bounds rectangle; the caller is responsible for sizing the rect so all text is visible. Content is either a static localized string (see TextItem::new) or a reactive Signal<String> (see TextItem::with_signal_text). Both sources trigger a repaint on change without rebuilding the scene.

Implementations

impl TextItem

pub fn new(text: impl Into<LocalizedString>, local_bounds: Rect) -> Self

A static-text item in local coordinates. The text is resolved eagerly via LocalizedString::resolve_now at construction; locale changes rebuild the composite parent, which re-creates this TextItem with a fresh translation.

pub fn with_signal_text(text: Signal<String>, local_bounds: Rect) -> Self

A text item whose content is driven by a Signal<String>. register_bindings ties the signal to the SceneView at BindingLevel::RepaintOnly so changes dirty paint and the next walk reads the current value.

pub fn draggable(self, draggable: bool) -> Self

Opt the text into drag-to-move.

pub fn color(self, color: impl Into<ColorProp>) -> Self

Override the foreground colour. Accepts a plain [Color], a theme role, a Signal<Color>, or a Signal<Role> — resolved against the active theme at paint time.

pub fn align(self, align: TextAlign) -> Self

Horizontal alignment within local_bounds. Default TextAlign::Leading. Needs a text backend to measure the text width; a headless canvas with no backend renders leading-aligned.

pub fn rotation(self, radians: f32) -> Self

Rotate the text about the item’s centre by radians. Default 0.0 (upright). Pair with Signal::animate_to on a driving signal for animated rotation, or set a fixed angle for a vertical axis title.

pub fn follow_text_scale(self, follow: bool) -> Self

Opt this text into the global accessibility text scale, so it grows with the app-wide “grow all text” setting. Off by default — the scene’s own pan/zoom usually governs scene text size.

pub fn label(self, label: impl Into<LocalizedString>) -> Self

Override the AT label (defaults to the current text content).

pub fn measure(&self, backend: &mut dyn TextBackend) -> Size

Measure the current text’s single-line intrinsic size against backend at the authored TextStyle. Lets a consumer size a slot around a label (axis labels, value tags) before placing it. Does not apply the global text scale — measure at the authored size.

pub fn access_label(self, label: impl Into<LocalizedString>) -> Self

Override the AT name announced for this item. Accepts anything convertible into LocalizedString — most commonly tr!(...) for translated labels, or any plain string (which auto-converts via From<String>).

pub fn access_description(self, description: impl Into<LocalizedString>) -> Self

Long-form context appended to the item’s announcement.

pub fn access_role(self, role: Role) -> Self

Override the AccessKit role for this item.

pub fn access_hidden(self, hidden: bool) -> Self

Hide this item from the AT tree.

pub fn access_subtree(self, mode: AccessSubtreeMode) -> Self

Set the AT subtree mode. Merge collapses descendants into this item’s AT node; Exclude prunes them; the default Inherit lets them emit normally.

pub fn access_merge_subtree(self) -> Self

Convenience: collapse all descendants into this item’s AT node so the subtree reads as one element.

pub fn access_exclude_subtree(self) -> Self

Convenience: prune all descendants from the AT tree.

pub fn access_value(self, value: impl Into<LocalizedString>) -> Self

Announce a string value for this item (e.g. a formatted data reading like "42 %"). Mirrors the widget-tier .access_value.

pub fn access_numeric_value(self, value: f64) -> Self

Announce a numeric value for this item, for slider/gauge-like data marks whose magnitude assistive tech should describe. Pair with access_numeric_range / access_numeric_step for full range semantics.

pub fn access_numeric_range(self, min: f64, max: f64) -> Self

Announce the numeric min/max bounds for this item.

pub fn access_numeric_step(self, step: f64) -> Self

Announce the numeric step (per-arrow increment) for this item.

Trait Implementations

impl Debug for TextItem

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

Formats the value using the given formatter.

impl SceneItem for TextItem

fn local_bounds(&self) -> Rect

AABB in local item coordinates (origin at the item’s anchor). The Scene composes this with the item’s scene_transform to compute its scene-space AABB for the spatial index.

fn set_local_bounds(&mut self, bounds: Rect)

Write back new bounds. Called by Scene::set_local_bounds when the bounds change. Implementations update their stored bounds field; geometry-bearing items (e.g. crate::PathItem) must keep their geometry consistent with the new bounds.

fn paint(&self, canvas: &mut Canvas, ctx: &SceneItemPaintContext<'_>)

Paint the item into the canvas. The canvas already has this item’s scene_transform (parent chain × view) pushed, so coordinates are in local item space — (0, 0) is the item’s anchor.

fn set_fill(&mut self, fill: Option<ColorProp>) -> bool

Replace the primary fill colour, returning true if this item kind has a fill slot that accepted the change. Backs SceneModel::set_item_fill / clear_item_fill. Rectangles, paths, and groups set their fill; text items map it onto their foreground colour (so a None is rejected — text always has a colour); image items have no fill and return false. Default: no-op.

fn label(&self) -> Option<String>

Optional human-readable label, surfaced in debug introspection and used by the default SceneItem::accessibility impl as the AT name when an item author hasn’t overridden it via the per-item .access_label(...) chain.

fn initial_flags(&self) -> ItemFlags

The flags this item should carry into the Scene at insert time. Default: ItemFlags::default() — visible, enabled, selectable. Built-ins read their accumulated builder state (e.g. .draggable(true) flips IS_DRAGGABLE); custom items override this to opt into hover acceptance, focus, clipping, or IGNORES_TRANSFORMATIONS.

fn access_subtree_mode(&self) -> AccessSubtreeMode

AT subtree treatment for descendants.

fn accessibility( &self, builder: &mut AccessNodeBuilder, _ctx: &SceneItemA11yContext, )

Populate the AccessKit node for this item. Default: role [Role::GraphicsObject] plus the SceneItem::label as the AT name if set. The per-item .access_* builder chain layers overrides on top of whatever this method writes.

fn register_bindings(&self, ctx: &mut BuildContext<'_>, view_id: WidgetId)

Register reactive bindings the item depends on. Called once per SceneView::build for every item in the scene, with the SceneView’s WidgetId as view_id. Items with signal-bound state bind their signals here at the appropriate BindingLevel.

fn set_stroke(&mut self, stroke: Option<(ColorProp, StrokeStyle)>) -> bool

Replace the stroke (colour + [StrokeStyle]), returning true if this item kind has a stroke slot that accepted the change. Backs SceneModel::set_item_stroke / clear_item_stroke. Rectangles, paths, and groups accept it; text and image items return false. Default: no-op.

fn shape_contains(&self, local_pt: Point) -> bool

Exact-shape hit-test in local coordinates. Default: AABB containment via SceneItem::local_bounds. Path-based items override this to do per-segment distance checks so users can click along a stroke even when the AABB is huge.

fn clone_shape_test(&self) -> Box<dyn Fn(Point, f32) -> bool + 'static>

Produce a stand-alone Fn(Point, f32) -> bool that closes over whatever state this item needs to answer shape_contains without retaining a borrow on self. The SceneView snapshots one of these for every item at layout time and consults it on every pointer event — direct calls to shape_contains(&self, ...) can’t be cached because &dyn SceneItem is not Clone.

fn thumbnail_color(&self) -> Color

Dominant color to draw as the item’s representation in minimap-style thumbnails. Default: an opaque mid-grey, which gives a recognisable but neutral marker for any item. Built-in items override: RectItem returns its fill, PathItem returns stroke or fill, ImageItem returns the image’s dominant tint placeholder.

fn cache_mode(&self) -> CacheMode

Per-item paint caching strategy. Default CacheMode::None: the item’s paint runs every frame.