Struct Spin 

pub struct Spin {
    pub left: u32,
    pub origin: (f64, f64),
    pub step: (f64, f64),
    pub made: u32,
    pub pressed: bool,
}

A measured camera spin: an orbit drag the app steps ITSELF, one pointer move per frame, from perf_spin. See BrepApp::spin for why it is not driven from outside.

The steps run through the same EngineState::pointer_down/move/up the viewport’s real drag uses (see viewport::interaction), so a spin costs exactly what dragging the mouse costs — no shortcut past the controls.

Fields

left: u32

Pointer steps still to make; the drag ends (pointer_up) on the last one.

origin: (f64, f64)

Where the drag started, in viewport-local logical px.

step: (f64, f64)

Pointer step, in viewport-local logical px per frame.

made: u32

Steps already made — the drag is a straight sweep from origin, and reversing at the halfway mark keeps it inside the viewport however many frames are asked for.

pressed: bool

False until the first frame has pressed the button.