Enum TransformHandle 

#[non_exhaustive]
pub enum TransformHandle {
    Move,
    TopLeading,
    Top,
    TopTrailing,
    Leading,
    Trailing,
    BottomLeading,
    Bottom,
    BottomTrailing,
    Rotate,
}

One grab affordance on the selection frame.

Move is the frame band itself (and the body of a selected item); Rotate is the detached puck above the top edge; the other eight are the resize anchors.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Move

The frame band — drag it to move the whole selection.

TopLeading

Top-leading corner.

Top

Top edge midpoint.

TopTrailing

Top-trailing corner.

Leading

Leading edge midpoint.

Trailing

Trailing edge midpoint.

BottomLeading

Bottom-leading corner.

Bottom

Bottom edge midpoint.

BottomTrailing

Bottom-trailing corner.

Rotate

The rotate puck, above the top edge.

Implementations

impl TransformHandle

pub const fn op(self) -> TransformOp

Which operation dragging this handle performs.

pub const fn cursor(self) -> CursorIcon

The pointer cursor for this handle, in an unrotated frame. A rotated frame keeps these — the four diagonal / axis cursors do not have enough resolution to track an arbitrary angle, and guessing wrong is worse than a cursor that is merely approximate.

pub const fn is_scalar(self) -> bool

Whether this handle’s state is one number or two.

An edge midpoint carries the coordinate of the edge it drags; the rotate puck carries an angle. Both are one number, so both are a Slider with a numeric_value, and Increment / Decrement mean exactly “make that number bigger / smaller”.

A corner carries two coordinates and the frame band carries the whole selection’s position, so neither has a single value to announce. They are Buttons, and their one-dimensional verbs move both coordinates — see at_steps.

Three things read this and must agree: the published role, whether a numeric_value is set, and what one assistive-technology verb does.

pub const fn at_steps(self, increment: bool) -> &'static [TransformStep]

The steps one assistive-technology Increment (or Decrement) is made of, as directions the keyboard route already understands.

One rule covers every handle: a step moves each coordinate the handle drives by +1 (Increment) or -1 (Decrement), and leaves the rest alone.

For a scalar handle that is the coordinate its numeric_value announces, which is what makes the slider contract true: Increment on “Resize bottom” raises the bottom edge’s y, and the announced number goes up by one. Before this existed every verb was a horizontal nudge, so Top and Bottom reported “handled” and moved nothing at all — the item’s height could not be changed by any assistive-technology route.

For a corner the same rule gives the diagonal: Increment on “Resize top leading” moves that corner’s x and y up by one, which is exactly Increment on “Resize top” plus Increment on “Resize leading” — the two edges the corner sits between, together. That is the only motion a corner can express with a one-dimensional verb, and it keeps the corner reachable when a configuration offers corners and nothing else. A user who needs one axis at a time reaches it through the four named custom actions a non-scalar handle also publishes (see TransformStep); the frame band works the same way.

Trait Implementations

impl Clone for TransformHandle

fn clone(&self) -> TransformHandle

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TransformHandle

impl Debug for TransformHandle

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

Formats the value using the given formatter.

impl Eq for TransformHandle

impl Hash for TransformHandle

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for TransformHandle

fn cmp(&self, other: &TransformHandle) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for TransformHandle

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for TransformHandle

fn partial_cmp(&self, other: &TransformHandle) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for TransformHandle