Struct Line 

pub struct Line {
    pub a: Point,
    pub b: Point,
}

A two-point measurement: a ruler laid on the frozen image.

Not a Shape. A measure has no interior, no crop, no cutout contribution and no click point, so putting it through the selection path would make assert, emit, find, and the crop writer each grow a special case for a thing none of them can answer about.

Fields

a: Point

b: Point

Implementations

impl Line

pub const fn new(a: Point, b: Point) -> Self

pub const fn delta(self) -> (i32, i32)

Signed horizontal and vertical extent, b - a.

Saturating, because the answer is an i32 and the true difference between two i32s need not be one. Screen coordinates never come close, but a session is a file a human can edit, and a bounded number beats a panic when the input was already meaningless. Self::length and Self::angle_deg do not go through this — they widen to f64 first and stay exact at any input.

pub fn length(self) -> f64

Euclidean length in pixels.

pub fn angle_deg(self) -> f64

Direction in degrees within [0, 360), 0 pointing right along +X and increasing clockwise.

Clockwise because screen Y grows downward: a ruler dragged visually down-and-right has to read as a positive angle, which the mathematical convention would report as negative.

A zero-length measure has no direction; it reports 0.0 rather than the NaN atan2(0, 0) would be entitled to.

pub fn bbox(self) -> Rect

The smallest rect containing both endpoints — what the caption placement needs, since a line has no Shape::bbox.

pub const fn translated(self, dx: i32, dy: i32) -> Self

pub fn endpoint_grab(self, p: Point, tolerance: i32) -> Option<bool>

The endpoint p grabs, if either is within tolerance.

a wins a tie: the two coincide only on a zero-length measure, where the choice cannot matter, and preferring one keeps the pick deterministic.

pub fn hit_test(self, p: Point, tolerance: i32) -> bool

Whether p is within tolerance of the segment — the whole-line grab, used after the endpoints have had their chance.

pub fn distance_to(self, p: Point) -> f64

Shortest distance from p to the segment, clamped at the ends so a point beyond b measures to b rather than to the infinite line through it.

pub fn constrained(self) -> Self

b snapped to the nearest horizontal, vertical, or 45° direction from a — what Shift does while dragging, matching the constraint the other tools apply.

The length along the chosen direction is preserved as the projection of the free endpoint onto it, so the ruler tracks the pointer instead of jumping to a fixed radius.

Trait Implementations

impl Clone for Line

fn clone(&self) -> Line

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Line

impl Debug for Line

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

Formats the value using the given formatter.

impl Eq for Line

impl From<Line> for LineRecord

fn from(line: Line) -> Self

Converts to this type from the input type.

impl PartialEq for Line

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Line