Struct ImageGeometry 

#[non_exhaustive]
pub struct ImageGeometry {
    pub source: (u32, u32),
    pub orientation: ImageOrientation,
    pub content: Rect,
    pub bounds: Rect,
}

The placement of a source raster in a widget’s box, and the mapping between the box’s points and the source’s pixels.

compute places it; snapped moves the picture’s edges onto the device-pixel grid. A widget computes it once per layout, paints from it and maps input through it, so the pixel under the pointer is the pixel drawn there.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

source: (u32, u32)

The source size in pixels, before orientation.

orientation: ImageOrientation

How the source is turned for display.

content: Rect

Where the whole displayed picture lies, widget-local. It exceeds bounds where the fit crops.

bounds: Rect

The widget’s box, widget-local: its origin is (0, 0).

Implementations

impl ImageGeometry

pub fn new( source: (u32, u32), orientation: ImageOrientation, content: Rect, bounds: Rect, ) -> ImageGeometry

A placement computed elsewhere: content is where the whole displayed picture lies inside bounds, both widget-local.

pub fn compute( bounds: Size, source: (u32, u32), fit: ImageFit, alignment: Alignment, rtl: bool, orientation: ImageOrientation, ) -> ImageGeometry

A source-sized raster turned by orientation and fitted into a box of size bounds by fit, placed by alignment (rtl resolving Leading and Trailing). Not snapped.

pub fn snapped(self, to_device: Transform2D) -> ImageGeometry

The same placement with the picture’s four edges moved to the nearest device-pixel boundary.

to_device maps a widget-local point to device pixels: the widget’s window origin, any transform its ancestors apply, then the HiDPI scale. Snapping applies only when that keeps edges on edges, a transform with no rotation or shear; any other returns the placement unchanged. An edge moves by at most half a device pixel, and an axis snapping would collapse keeps its unsnapped edges. Snapping twice changes nothing more.

pub fn snaps_under(to_device: Transform2D) -> bool

Whether snapped moves edges under to_device: a transform with no rotation or shear, and a finite scale other than zero on both axes. A placement is the same under any two transforms it does not snap under.

pub fn displayed(&self) -> (u32, u32)

The source size as displayed: swapped for a quarter turn.

pub fn visible(&self) -> Option<Rect>

The part of the picture inside the box, widget-local; None when the two do not overlap.

pub fn map_to_source(&self, local: Point) -> Option<(u32, u32)>

The source pixel whose displayed square contains local, or None on the letterbox, outside the box, or with nothing to show.

pub fn map_to_source_clamped(&self, local: Point) -> Option<(u32, u32)>

The source pixel nearest local: the point is clamped into the picture first. None only with nothing to show.

pub fn map_to_source_f32(&self, local: Point) -> Option<(f32, f32)>

Continuous source coordinates of local, unclamped: pixel k spans [k, k + 1). None only with nothing to show.

pub fn map_from_source(&self, rect: PixelRect) -> Option<Rect>

Where the source pixels of rect are displayed, widget-local: the bounding box of their displayed squares. None when rect is empty or does not lie inside the source.

Trait Implementations

impl Clone for ImageGeometry

fn clone(&self) -> ImageGeometry

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ImageGeometry

impl Debug for ImageGeometry

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

Formats the value using the given formatter.

impl PartialEq for ImageGeometry

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ImageGeometry