Struct InteractiveView 

pub struct InteractiveView {
    pub scale: f32,
    pub tx: f32,
    pub ty: f32,
}

The retained state of an InteractiveViewer: the scale factor and the translation applied to the child. The screen point q receives the content painted flat at p according to q = scale · p + (tx, ty). The identity (scale = 1, zero translation) places the child as is in the viewport.

All the gesture mathematics lives here (pure, testable): the shell merely calls pan and zoom_at, then renders the matrix.

Fields

scale: f32

The current scale factor (1.0 = natural size).

tx: f32

The paint translation, in logical pixels.

ty: f32

The paint translation along the y axis, in logical pixels; tx is the x axis.

Implementations

impl InteractiveView

pub fn matrix(&self) -> Affine

The matrix q = scale · p + t (scaling about the origin, then translation).

pub fn pan(self, dx: f32, dy: f32) -> Self

Pans the content by (dx, dy) screen pixels: the finger or cursor pushes the content by the same delta.

pub fn clamped(self, viewport: Rect) -> Self

Clamps the translation so that the content (at the current scale) always covers the viewport: an edge of the content cannot be dragged inside the viewport. When the content is smaller than the viewport (zoomed out below 1), it is centred. At scale 1, panning is nil (the content fills exactly).

pub fn zoom_at(self, factor: f32, cursor: Point, min: f32, max: f32) -> Self

Zooms by factor while keeping the screen point cursor fixed (a cursor-anchored zoom), with the final scale clamped to [min, max]. The point of the content under the cursor does not move — the behaviour expected of a wheel or a pinch.

Trait Implementations

impl Clone for InteractiveView

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for InteractiveView

impl Debug for InteractiveView

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

Formats the value using the given formatter.

impl Default for InteractiveView

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for InteractiveView

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for InteractiveView