Struct OverlayTransform 

pub struct OverlayTransform { /* private fields */ }

A uniform similarity transform mapping the reference canvas to the live window: a single scale plus a recentering. Built from the live viewport; an invalid (zero) viewport yields the identity (overlay drawn at reference pixels), which is what unit tests and the pre-backend init frames see.

Implementations

impl OverlayTransform

pub fn from_viewport(viewport: [f32; 2]) -> Self

Build the transform for a live logical viewport [width, height]. A degenerate viewport gives the identity transform.

pub fn cover_from_viewport(viewport: [f32; 2]) -> Self

Build the “cover” transform for a live logical viewport: the larger axis ratio, so the reference canvas always fills the window (the overflowing axis is cropped equally on both sides). Used by full-bleed stage imagery (scene backdrops, character portraits) that must reach the window edges without distorting; the canvas bottom maps at or below the window bottom, so bottom-anchored content stays flush at any aspect ratio.

pub fn bottom_anchored_from_viewport(viewport: [f32; 2]) -> Self

Build the “bottom-anchored” transform for a live logical viewport: the fit scale (no cropping, elements keep their proportions), but shifted vertically so the reference bottom edge (y = reference height) maps to the window bottom. Bottom-anchored overlay furniture (a dialog box and its controls) hugs the window bottom at any aspect ratio, where a plain fit would float it above the letterbox margin.

pub fn scale(&self) -> f32

The uniform scale factor applied to sizes (glyph scale, sprite extent).

pub fn forward(&self, x: f32, y: f32) -> (f32, f32)

Map a reference-space point to window space.

pub fn inverse(&self, x: f32, y: f32) -> (f32, f32)

Map a window-space point back to reference space (the inverse of forward). Used to hit-test the live cursor against reference-space UI rects.

Trait Implementations

impl Clone for OverlayTransform

fn clone(&self) -> OverlayTransform

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for OverlayTransform

impl Debug for OverlayTransform

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

Formats the value using the given formatter.