Enum gdk4::ScrollUnit

#[non_exhaustive]
pub enum ScrollUnit {
    Wheel,
    Surface,
}

Available on crate feature v4_8 only.

Specifies the unit of scroll deltas.

When you get Wheel, a delta of 1.0 means 1 wheel detent click in the south direction, 2.0 means 2 wheel detent clicks in the south direction… This is the same logic for negative values but in the north direction.

If you get Surface, are managing a scrollable view and get a value of 123, you have to scroll 123 surface logical pixels right if it’s @delta_x or down if it’s @delta_y. This is the same logic for negative values but you have to scroll left instead of right if it’s @delta_x and up instead of down if it’s @delta_y.

1 surface logical pixel is equal to 1 real screen pixel multiplied by the final scale factor of your graphical interface (the product of the desktop scale factor and eventually a custom scale factor in your app).

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.

Wheel

The delta is in number of wheel clicks.

Surface

The delta is in surface pixels to scroll directly on screen.

Trait Implementations

impl Clone for ScrollUnit

fn clone(&self) -> ScrollUnit

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ScrollUnit

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

Formats the value using the given formatter.

impl From<ScrollUnit> for Value

fn from(v: ScrollUnit) -> Self

Converts to this type from the input type.

impl<'a> FromValue<'a> for ScrollUnit

type Checker = GenericValueTypeChecker<ScrollUnit>

Value type checker.

unsafe fn from_value(value: &'a Value) -> Self

Get the contained value from a Value.

impl HasParamSpec for ScrollUnit

type ParamSpec = ParamSpecEnum

type SetValue = ScrollUnit

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(_: &str, _: ScrollUnit) -> ParamSpecEnumBuilder<'_, ScrollUnit>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for ScrollUnit

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 ScrollUnit

fn cmp(&self, other: &ScrollUnit) -> 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 + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for ScrollUnit

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for ScrollUnit

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

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

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

This method tests less than (for self and other) and is used by the < operator.

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

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

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

This method tests greater than (for self and other) and is used by the > operator.

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

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

impl StaticType for ScrollUnit

fn static_type() -> Type

Returns the type identifier of Self.

impl ToValue for ScrollUnit

fn to_value(&self) -> Value

Convert a value to a Value.

fn value_type(&self) -> Type

Returns the type identifier of self.

impl ValueType for ScrollUnit

type Type = ScrollUnit

Type to get the Type from.

impl Copy for ScrollUnit

impl Eq for ScrollUnit

impl StructuralPartialEq for ScrollUnit