Struct ImageWidget 

pub struct ImageWidget { /* private fields */ }

A widget that displays a raster image (PNG, WebP, or raw RGBA pixels) with configurable fit and alignment.

Implementations

impl ImageWidget

pub fn new(icon: &RasterIcon) -> Self

Create from a decoded [RasterIcon] (e.g., from res!()).

pub fn from_raw(pixels: Vec<u8>, width: u32, height: u32) -> Self

Create from raw RGBA pixel data.

Each call gets a unique texture-atlas key (via a process-local atomic counter), so two from_raw widgets with the same dimensions but different bytes don’t alias in the renderer’s pending-image cache. Without this, the first writer per frame would silently win and subsequent ones would render the wrong pixels — a latent bug fixed alongside the dynamic-image use cases that need many short-lived from_raw widgets.

pub fn mask(self, shape: ImageMaskShape) -> Self

Apply an anti-aliased alpha mask to the image at construction time. The pixels are first centre-cropped to the shorter side (so the mask shape is geometrically consistent regardless of the source aspect ratio), then their alpha channel is modulated by the mask coverage. RGB is preserved.

Cover fit is the natural pairing — the masked square fills the avatar/thumbnail bounds and the masked-out corners stay transparent. Contain works but may letterbox. The default fit (Contain) is left unchanged so callers explicitly pick a fit when they apply a mask.

ImageMaskShape::None is a no-op. Re-uploading is keyed off a fresh per-mask name so the un-masked version of the same source doesn’t shadow the masked one in the texture atlas.

pub fn fit(self, fit: ImageFit) -> Self

Set the content-fit mode — how the image pixels map into the box. See ImageFit.

pub fn alignment(self, alignment: Alignment) -> Self

Set where the fitted image sits within the box when the active fit leaves slack or crops (the CSS object-position analogue). Defaults to [Alignment::CENTER]. Leading/Trailing resolve against the active layout direction (RTL-aware).

pub fn width(self, w: f32) -> Self

Pin a fixed display width (in logical pixels). The width axis becomes rigid — reported as-is and never scaled to a parent proposal. With no height pinned, the height derives from the image’s aspect ratio (CSS width: Npx; height: auto).

pub fn height(self, h: f32) -> Self

Pin a fixed display height (in logical pixels). The height axis becomes rigid. With no width pinned, the width derives from the image’s aspect ratio.

pub fn size(self, w: f32, h: f32) -> Self

Pin both display width and height (in logical pixels). The box is exactly this size, rigid on both axes; the image content is fitted inside it via the fit mode. This is the fixed-size-logo case — .size(32.0, 32.0).

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

Control whether, with no axis pinned, a constraining parent proposal scales the natural pixel size (true, the default) or the box stays locked to the raw pixel dimensions (false). Equivalent to opting out of SwiftUI’s .resizable(). No effect once a dimension is pinned via width / height / size.

pub fn alt(self, text: impl Into<String>) -> Self

Set the accessibility alt text.

pub fn a11y_hidden(self) -> Self

Mark this image as decorative — hidden from the accessibility tree. Use when the image’s semantic content is already conveyed by adjacent text (e.g. a hero image next to its caption). ARIA equivalent of alt="" / role="presentation".

Trait Implementations

impl Debug for ImageWidget

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

Formats the value using the given formatter.

impl Widget for ImageWidget

fn layout_response( &self, proposal: SizeProposal, _ctx: &LayoutContext<'_>, ) -> LayoutResponse

Respond to the parent’s size proposal with this widget’s wanted size, grow/shrink weights, and compression floor (see [LayoutResponse]).

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

Draw the widget’s visual representation.

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

Declare this widget’s accessibility identity.

fn type_name(&self) -> &'static str

Concrete type name of this widget (e.g. "teksilo_widgets::button::Button"). The default implementation resolves at the impl site via std::any::type_name::<Self>(), so calls through &dyn Widget correctly dispatch to the monomorphized fn for the concrete type — getting the concrete name through the vtable without per-impl boilerplate.

fn build(&mut self, _ctx: &mut BuildContext<'_>) -> Vec<WidgetId>

Compose child widgets. Called once after the widget is placed in the arena, and again on environment change (theme switch, locale switch). Takes &mut self — store child IDs, signal handles, any state needed later. Returns the list of root child IDs (empty for leaf widgets).

fn cacheable_layout(&self) -> bool

Whether this widget’s layout_response may be memoized by the per-pass layout cache. Defaults to true.

fn place_children( &self, _bounds: Rect, _proposal: SizeProposal, _children: &mut [WidgetPlacement], _ctx: &LayoutContext<'_>, )

Position children within the allocated bounds.

fn wants_after_paint(&self) -> bool

Whether this widget wants its after_paint hook to fire each frame. Returning false (the default) saves a virtual call per widget per frame for the vast majority of widgets that don’t aggregate descendant geometry.

fn after_paint(&self, _view: &WidgetTreeView<'_>, _ctx: &PaintContext<'_>)

Called once per frame after this widget’s subtree has finished painting. Receives a read-only view of the layout-resolved arena so a parent can read its descendants’ final bounds — e.g. TitleBar aggregates its drag region and control-button rects into a single HitRegions payload for the Windows backend’s WM_NCHITTEST.

fn wants_post_paint(&self) -> bool

Whether this widget wants its post_paint hook to fire each frame. Returning false (the default) saves a virtual call per widget per frame for the vast majority of widgets that don’t draw a foreground over their children.

fn post_paint( &self, _bounds: Rect, _canvas: &mut Canvas, _ctx: &PaintContext<'_>, )

Draw a foreground layer over this widget’s children.

fn wants_descendant_redirects(&self) -> bool

Whether this widget wants the AT walker to consult its a11y_redirect_descendant hook for every descendant during AT tree emission, not just its direct arena children.

fn a11y_redirect_descendant( &self, _self_id: WidgetId, _descendant: WidgetId, ) -> Option<NodeId>

Optional redirection hook for AT-tree placement of a child.

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

Suggest an accessible title to an enclosing container that wraps this widget as content — typically a modal / dialog shell that wants to propagate the inner content’s visible title as the shell’s own accessible name.

fn initial_focus_hint(&self) -> Option<WidgetId>

Optional hint that directs initial focus to a specific descendant when this widget is the root of a deferred-built modal surface.

fn children(&self) -> Vec<WidgetId>

Return the child widget IDs that this widget manages.

fn accessibility_children(&self) -> Option<Vec<WidgetId>>

Optional override for the child ORDER presented to assistive technology, when it must differ from the paint / z-order child order returned by children.

fn as_any(&self) -> Option<&(dyn Any + 'static)>

Downcast hook. Default implementation returns None; concrete widgets override with Some(self) when they want to expose their concrete type to test-level introspection or reflection. The trait already bounds on std::any::Any so concrete types satisfy the 'static requirement.

fn as_any_mut(&mut self) -> Option<&mut (dyn Any + 'static)>

Mutable counterpart of as_any. Default returns None; widgets that want to expose mutable state to tests (e.g. so a test can mutate a Scene inside a SceneView post-layout) override with Some(self). Should follow the same opt-in pattern as as_any: only widgets that opt into & introspection should opt into &mut.

fn clips_children(&self) -> bool

Whether this widget clips its children to its bounds.

fn focus_reveal_rect(&self, _bounds: Rect) -> Option<Rect>

The rectangle (in absolute tree coordinates) that best represents this widget when the framework reveals it into an ancestor scroll area on focus gain. Returning None (the default) reveals the widget’s whole bounds — correct for most controls.

fn hit_shape(&self, _local_point: Point, _bounds: Rect) -> bool

Whether the point lies inside this widget’s actual shape, not just its rectangular bounds. Consulted by hit-testing right after the bounds check: returning false for a point that is inside the bounding box makes the widget transparent to the click there, so it falls through to whatever sibling is painted underneath (the same machinery as a fully pass-through node, but shape-aware).

fn preserves_children_on_rebuild(&self) -> bool

How rebuild_single_widget treats this widget’s existing children when re-running its build().

fn tooltip_has_content(&self) -> bool

Whether this widget, used as tooltip content, currently has anything worth showing.

fn declare_shortcuts(&self) -> Vec<Shortcut>

Declare the rebindable keyboard shortcuts this widget exposes, without installing handlers. The framework calls this at arena insertion time (before build()) and at certain lazy boundaries (e.g. Switcher walks declarations on its not-yet-mounted Pending slots), so settings UIs and the ShortcutRegistry see the keystrokes the moment the owning container mounts — even if build() hasn’t run.

fn take_handler_set(&mut self) -> Option<HandlerSet>

Extract attached handler set from a WidgetWithHandlers wrapper. Called during arena insertion to transfer handlers to the WidgetNode. Default: returns None (no attached handlers).