Struct nannou::ui::widget::scroll::State [−][src]
pub struct State<A> { pub offset: f64, pub offset_bounds: Range, pub scrollable_range_len: f64, pub is_scrolling: bool, // some fields omitted }
Scroll state calculated for a single axis.
Fields
offset: f64
The distance that has been scrolled from the origin.
A positive offset pushes the scrollable range that is under the kid_area upwards.
A negative offset pushes the scrollable range that is under the kid_area downwards.
offset_bounds: Range
The start and end bounds for the offset along the axis.
scrollable_range_len: f64
The total range which may be "offset" from the "root" range (aka the kid_area
).
The scrollable_range
is determined as the bounding range around both the kid_area
and
all un-scrolled visible children widgets.
is_scrolling: bool
Whether or not the this axis is currently scrolling.
Methods
impl<A> State<A> where
A: Axis,
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impl<A> State<A> where
A: Axis,
pub fn update(
ui: &Ui,
idx: NodeIndex<u32>,
kid_area: &KidArea,
maybe_prev_scroll_state: Option<State<A>>,
additional_offset: f64
) -> State<A>
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pub fn update(
ui: &Ui,
idx: NodeIndex<u32>,
kid_area: &KidArea,
maybe_prev_scroll_state: Option<State<A>>,
additional_offset: f64
) -> State<A>
Calculate the new scroll state for the single axis of a Widget
.
> +---+
| | |
| =========================
| | | a | scroll root |
| | +---+ aka `kid_area` |
| | +--------+ |
| | | | |
| =========================
| | b |
| +--------+
scrollable| +--------+
range y| | |
| | | +------+
| | c | | |
| +--------+ | d |
| | |
> +------+
^--------------------^
scrollable
range x
kid_area
is the cropped area of the container widget in which kid widgets may be viewed.a
,b
,c
andd
are widgets that are kids of the "scroll root" widget in their original, un-scrolled positions.scrollable_range
is the total range occuppied by all children widgets in their original, un-scrolled positions.
Everything above and below the set of ==== bars of the parent widget is hidden, i.e:
=========================
| | a | scroll root |
| +---+ aka `kid_area` |
| +--------+ |
| | b | |
=========================
The scrollable_range
on each axis only becomes scrollable if its length exceeds the
length of the kid_area
on the same axis. Thus, in the above example, only the y
scrollable_range is scrollable.
The offset_bounds
are calculated as the amount which the original, un-scrolled,
scrollable_range
may be offset from its origin.
offset + >
bounds v |
.start > | =========================
| | |
| | kid_area |
| | |
| | |
> scrollable | =========================
^ range y |
^ |
^ |
offset ^ |
bounds ^ |
.end ^ |
^ |
^ |
+ >
Trait Implementations
impl<A> Clone for State<A> where
A: Clone,
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impl<A> Clone for State<A> where
A: Clone,
fn clone(&self) -> State<A>
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fn clone(&self) -> State<A>
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
1.0.0[src]
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
impl<A> Debug for State<A> where
A: Debug,
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impl<A> Debug for State<A> where
A: Debug,
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>
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fn fmt(&self, f: &mut Formatter) -> Result<(), Error>
Formats the value using the given formatter. Read more
impl<A> Copy for State<A> where
A: Copy,
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impl<A> Copy for State<A> where
A: Copy,
impl<A> PartialEq<State<A>> for State<A> where
A: PartialEq<A>,
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impl<A> PartialEq<State<A>> for State<A> where
A: PartialEq<A>,