//! Distribute content vertically.
use crate::core::event::{self, Event};
use crate::core::layout;
use crate::core::mouse;
use crate::core::overlay;
use crate::core::renderer;
use crate::core::widget::tree::{self, Tree};
use crate::core::widget::Operation;
use crate::core::{
Alignment, Clipboard, Element, Layout, Length, Padding, Pixels, Rectangle,
Shell, Widget,
};
/// A container that distributes its contents vertically.
#[allow(missing_debug_implementations)]
pub struct Column<'a, Key, Message, Renderer = crate::Renderer>
where
Key: Copy + PartialEq,
{
spacing: f32,
padding: Padding,
width: Length,
height: Length,
max_width: f32,
align_items: Alignment,
keys: Vec<Key>,
children: Vec<Element<'a, Message, Renderer>>,
}
impl<'a, Key, Message, Renderer> Column<'a, Key, Message, Renderer>
where
Key: Copy + PartialEq,
{
/// Creates an empty [`Column`].
pub fn new() -> Self {
Self::with_children(Vec::new())
}
/// Creates a [`Column`] with the given elements.
pub fn with_children(
children: impl IntoIterator<Item = (Key, Element<'a, Message, Renderer>)>,
) -> Self {
let (keys, children) = children.into_iter().fold(
(Vec::new(), Vec::new()),
|(mut keys, mut children), (key, child)| {
keys.push(key);
children.push(child);
(keys, children)
},
);
Column {
spacing: 0.0,
padding: Padding::ZERO,
width: Length::Shrink,
height: Length::Shrink,
max_width: f32::INFINITY,
align_items: Alignment::Start,
keys,
children,
}
}
/// Sets the vertical spacing _between_ elements.
///
/// Custom margins per element do not exist in iced. You should use this
/// method instead! While less flexible, it helps you keep spacing between
/// elements consistent.
pub fn spacing(mut self, amount: impl Into<Pixels>) -> Self {
self.spacing = amount.into().0;
self
}
/// Sets the [`Padding`] of the [`Column`].
pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self {
self.padding = padding.into();
self
}
/// Sets the width of the [`Column`].
pub fn width(mut self, width: impl Into<Length>) -> Self {
self.width = width.into();
self
}
/// Sets the height of the [`Column`].
pub fn height(mut self, height: impl Into<Length>) -> Self {
self.height = height.into();
self
}
/// Sets the maximum width of the [`Column`].
pub fn max_width(mut self, max_width: impl Into<Pixels>) -> Self {
self.max_width = max_width.into().0;
self
}
/// Sets the horizontal alignment of the contents of the [`Column`] .
pub fn align_items(mut self, align: Alignment) -> Self {
self.align_items = align;
self
}
/// Adds an element to the [`Column`].
pub fn push(
mut self,
key: Key,
child: impl Into<Element<'a, Message, Renderer>>,
) -> Self {
self.keys.push(key);
self.children.push(child.into());
self
}
}
impl<'a, Key, Message, Renderer> Default for Column<'a, Key, Message, Renderer>
where
Key: Copy + PartialEq,
{
fn default() -> Self {
Self::new()
}
}
struct State<Key>
where
Key: Copy + PartialEq,
{
keys: Vec<Key>,
}
impl<'a, Key, Message, Renderer> Widget<Message, Renderer>
for Column<'a, Key, Message, Renderer>
where
Renderer: crate::core::Renderer,
Key: Copy + PartialEq + 'static,
{
fn tag(&self) -> tree::Tag {
tree::Tag::of::<State<Key>>()
}
fn state(&self) -> tree::State {
tree::State::new(State {
keys: self.keys.clone(),
})
}
fn children(&self) -> Vec<Tree> {
self.children.iter().map(Tree::new).collect()
}
fn diff(&self, tree: &mut Tree) {
let Tree {
state, children, ..
} = tree;
let state = state.downcast_mut::<State<Key>>();
tree::diff_children_custom_with_search(
children,
&self.children,
|tree, child| child.as_widget().diff(tree),
|index| {
self.keys.get(index).or_else(|| self.keys.last()).copied()
!= Some(state.keys[index])
},
|child| Tree::new(child.as_widget()),
);
if state.keys != self.keys {
state.keys = self.keys.clone();
}
}
fn width(&self) -> Length {
self.width
}
fn height(&self) -> Length {
self.height
}
fn layout(
&self,
tree: &mut Tree,
renderer: &Renderer,
limits: &layout::Limits,
) -> layout::Node {
let limits = limits
.max_width(self.max_width)
.width(self.width)
.height(self.height);
layout::flex::resolve(
layout::flex::Axis::Vertical,
renderer,
&limits,
self.padding,
self.spacing,
self.align_items,
&self.children,
&mut tree.children,
)
}
fn operate(
&self,
tree: &mut Tree,
layout: Layout<'_>,
renderer: &Renderer,
operation: &mut dyn Operation<Message>,
) {
operation.container(None, layout.bounds(), &mut |operation| {
self.children
.iter()
.zip(&mut tree.children)
.zip(layout.children())
.for_each(|((child, state), layout)| {
child
.as_widget()
.operate(state, layout, renderer, operation);
});
});
}
fn on_event(
&mut self,
tree: &mut Tree,
event: Event,
layout: Layout<'_>,
cursor: mouse::Cursor,
renderer: &Renderer,
clipboard: &mut dyn Clipboard,
shell: &mut Shell<'_, Message>,
viewport: &Rectangle,
) -> event::Status {
self.children
.iter_mut()
.zip(&mut tree.children)
.zip(layout.children())
.map(|((child, state), layout)| {
child.as_widget_mut().on_event(
state,
event.clone(),
layout,
cursor,
renderer,
clipboard,
shell,
viewport,
)
})
.fold(event::Status::Ignored, event::Status::merge)
}
fn mouse_interaction(
&self,
tree: &Tree,
layout: Layout<'_>,
cursor: mouse::Cursor,
viewport: &Rectangle,
renderer: &Renderer,
) -> mouse::Interaction {
self.children
.iter()
.zip(&tree.children)
.zip(layout.children())
.map(|((child, state), layout)| {
child.as_widget().mouse_interaction(
state, layout, cursor, viewport, renderer,
)
})
.max()
.unwrap_or_default()
}
fn draw(
&self,
tree: &Tree,
renderer: &mut Renderer,
theme: &Renderer::Theme,
style: &renderer::Style,
layout: Layout<'_>,
cursor: mouse::Cursor,
viewport: &Rectangle,
) {
for ((child, state), layout) in self
.children
.iter()
.zip(&tree.children)
.zip(layout.children())
{
child
.as_widget()
.draw(state, renderer, theme, style, layout, cursor, viewport);
}
}
fn overlay<'b>(
&'b mut self,
tree: &'b mut Tree,
layout: Layout<'_>,
renderer: &Renderer,
) -> Option<overlay::Element<'b, Message, Renderer>> {
overlay::from_children(&mut self.children, tree, layout, renderer)
}
}
impl<'a, Key, Message, Renderer> From<Column<'a, Key, Message, Renderer>>
for Element<'a, Message, Renderer>
where
Key: Copy + PartialEq + 'static,
Message: 'a,
Renderer: crate::core::Renderer + 'a,
{
fn from(column: Column<'a, Key, Message, Renderer>) -> Self {
Self::new(column)
}
}
