//! Display a widget over another.
use std::hash::Hash;
use iced_core::Rectangle;
use crate::{
event, layout, overlay, Clipboard, Element, Event, Hasher, Layout, Length,
Point, Size, Vector, Widget,
};
/// An element to display a widget over another.
#[allow(missing_debug_implementations)]
pub struct Tooltip<'a, Message, Renderer: self::Renderer> {
content: Element<'a, Message, Renderer>,
tooltip: Element<'a, Message, Renderer>,
tooltip_position: TooltipPosition,
}
impl<'a, Message, Renderer> Tooltip<'a, Message, Renderer>
where
Renderer: self::Renderer,
{
/// Creates an empty [`Tooltip`].
///
/// [`Tooltip`]: struct.Tooltip.html
pub fn new<T, H>(
content: T,
tooltip: H,
tooltip_position: TooltipPosition,
) -> Self
where
T: Into<Element<'a, Message, Renderer>>,
H: Into<Element<'a, Message, Renderer>>,
{
Tooltip {
content: content.into(),
tooltip: tooltip.into(),
tooltip_position,
}
}
}
/// The position of the tooltip. Defaults to following the cursor.
#[derive(Debug, PartialEq)]
pub enum TooltipPosition {
/// The tooltip will follow the cursor.
FollowCursor,
/// The tooltip will appear on the top of the widget.
Top,
/// The tooltip will appear on the bottom of the widget.
Bottom,
/// The tooltip will appear on the left of the widget.
Left,
/// The tooltip will appear on the right of the widget.
Right,
}
impl Default for TooltipPosition {
fn default() -> Self {
TooltipPosition::FollowCursor
}
}
impl<'a, Message, Renderer> Widget<Message, Renderer>
for Tooltip<'a, Message, Renderer>
where
Renderer: self::Renderer,
{
fn width(&self) -> Length {
self.content.width()
}
fn height(&self) -> Length {
self.content.height()
}
fn layout(
&self,
renderer: &Renderer,
limits: &layout::Limits,
) -> layout::Node {
self.content.layout(renderer, limits)
}
fn on_event(
&mut self,
event: Event,
layout: Layout<'_>,
cursor_position: Point,
messages: &mut Vec<Message>,
renderer: &Renderer,
clipboard: Option<&dyn Clipboard>,
) -> event::Status {
self.content.widget.on_event(
event,
layout,
cursor_position,
messages,
renderer,
clipboard,
)
}
fn draw(
&self,
renderer: &mut Renderer,
defaults: &Renderer::Defaults,
layout: Layout<'_>,
cursor_position: Point,
viewport: &Rectangle,
) -> Renderer::Output {
renderer.draw(
defaults,
cursor_position,
&self.content,
layout,
viewport,
)
}
fn hash_layout(&self, state: &mut Hasher) {
struct Marker;
std::any::TypeId::of::<Marker>().hash(state);
self.content.hash_layout(state);
}
fn overlay(
&mut self,
layout: Layout<'_>,
overlay_content_bounds: Option<Rectangle>,
cursor_position: Point,
) -> Option<overlay::Element<'_, Message, Renderer>> {
let bounds = layout.bounds();
if bounds.contains(cursor_position) {
let mut position = cursor_position;
if let Some(content_bounds) = overlay_content_bounds {
if TooltipPosition::FollowCursor != self.tooltip_position {
match self.tooltip_position {
TooltipPosition::Top | TooltipPosition::Bottom => {
let x = bounds.x + bounds.width * 0.5
- content_bounds.width * 0.5;
position = match self.tooltip_position {
TooltipPosition::Top => Point::new(
x,
bounds.y - content_bounds.height,
),
TooltipPosition::Bottom => Point::new(
x,
bounds.y
+ bounds.height
+ content_bounds.height,
),
_ => unreachable!(),
};
}
TooltipPosition::Left | TooltipPosition::Right => {
let y =
bounds.center_y() + content_bounds.height * 0.5;
position = match self.tooltip_position {
TooltipPosition::Left => Point::new(
bounds.x - content_bounds.width,
y,
),
TooltipPosition::Right => {
Point::new(bounds.x + bounds.width, y)
}
_ => unreachable!(),
};
}
_ => {}
}
}
}
Some(overlay::Element::new(
position,
Box::new(Overlay::new(&self.tooltip)),
))
} else {
None
}
}
}
struct Overlay<'a, Message, Renderer: self::Renderer> {
content: &'a Element<'a, Message, Renderer>,
}
impl<'a, Message, Renderer: self::Renderer> Overlay<'a, Message, Renderer>
where
Message: 'a,
Renderer: 'a,
{
pub fn new(content: &'a Element<'a, Message, Renderer>) -> Self {
Self { content }
}
}
impl<'a, Message, Renderer> crate::Overlay<Message, Renderer>
for Overlay<'a, Message, Renderer>
where
Renderer: self::Renderer,
{
fn layout(
&self,
renderer: &Renderer,
bounds: Size,
position: Point,
) -> layout::Node {
let space_below = bounds.height - position.y;
let space_above = position.y;
let limits = layout::Limits::new(
Size::ZERO,
Size::new(
bounds.width - position.x,
if space_below > space_above {
space_below
} else {
space_above
},
),
)
.width(self.content.width());
let mut node = self.content.layout(renderer, &limits);
node.move_to(position - Vector::new(0.0, node.size().height));
node
}
fn hash_layout(&self, state: &mut Hasher, position: Point) {
struct Marker;
std::any::TypeId::of::<Marker>().hash(state);
(position.x as u32).hash(state);
(position.y as u32).hash(state);
self.content.hash_layout(state);
}
fn draw(
&self,
renderer: &mut Renderer,
defaults: &Renderer::Defaults,
layout: Layout<'_>,
cursor_position: Point,
viewport: &Rectangle,
) -> Renderer::Output {
renderer.draw(
defaults,
cursor_position,
&self.content,
layout,
viewport,
)
}
}
/// The renderer of a [`Tooltip`].
///
/// Your [renderer] will need to implement this trait before being
/// able to use a [`Tooltip`] in your user interface.
///
/// [`Tooltip`]: struct.Tooltip.html
/// [renderer]: ../../renderer/index.html
pub trait Renderer: crate::Renderer {
/// The style supported by this renderer.
type Style: Default;
/// Draws a [`Tooltip`].
///
/// [`Tooltip`]: struct.Tooltip.html
fn draw<Message>(
&mut self,
defaults: &Self::Defaults,
cursor_position: Point,
content: &Element<'_, Message, Self>,
content_layout: Layout<'_>,
viewport: &Rectangle,
) -> Self::Output;
}
impl<'a, Message, Renderer> From<Tooltip<'a, Message, Renderer>>
for Element<'a, Message, Renderer>
where
Renderer: 'a + self::Renderer,
Message: 'a,
{
fn from(
column: Tooltip<'a, Message, Renderer>,
) -> Element<'a, Message, Renderer> {
Element::new(column)
}
}
