use std::any::Any;
use crate::{
iced::{
clipboard::dnd::{DndAction, DndEvent, SourceEvent},
event, mouse, overlay, Event, Length, Point, Rectangle,
},
iced_core::{
self, layout, renderer,
widget::{tree, Tree},
Clipboard, Shell,
},
iced_style,
widget::{container, Id, Widget},
Element,
};
pub fn dnd_source<
'a,
Message: 'static,
AppMessage: 'static,
D: iced::clipboard::mime::AsMimeTypes + Send + 'static,
>(
child: impl Into<Element<'a, Message>>,
) -> DndSource<'a, Message, AppMessage, D> {
DndSource::new(child)
}
pub struct DndSource<'a, Message, AppMessage, D> {
id: Id,
action: DndAction,
container: Element<'a, Message>,
drag_content: Option<Box<dyn Fn() -> D>>,
drag_icon: Option<Box<dyn Fn() -> (Element<'static, AppMessage>, tree::State)>>,
drag_threshold: f32,
_phantom: std::marker::PhantomData<AppMessage>,
}
impl<
'a,
Message: 'static,
AppMessage: 'static,
D: iced::clipboard::mime::AsMimeTypes + std::marker::Send + 'static,
> DndSource<'a, Message, AppMessage, D>
{
pub fn new(child: impl Into<Element<'a, Message>>) -> Self {
Self {
id: Id::unique(),
action: DndAction::Copy | DndAction::Move,
container: container(child).into(),
drag_content: None,
drag_icon: None,
drag_threshold: 8.0,
_phantom: std::marker::PhantomData,
}
}
pub fn with_id(child: impl Into<Element<'a, Message>>, id: Id) -> Self {
Self {
id,
action: DndAction::Copy | DndAction::Move,
container: container(child).into(),
drag_content: None,
drag_icon: None,
drag_threshold: 8.0,
_phantom: std::marker::PhantomData,
}
}
#[must_use]
pub fn action(mut self, action: DndAction) -> Self {
self.action = action;
self
}
#[must_use]
pub fn drag_content(mut self, f: impl Fn() -> D + 'static) -> Self {
self.drag_content = Some(Box::new(f));
self
}
#[must_use]
pub fn drag_icon(
mut self,
f: impl Fn() -> (Element<'static, AppMessage>, tree::State) + 'static,
) -> Self {
self.drag_icon = Some(Box::new(f));
self
}
#[must_use]
pub fn drag_threshold(mut self, threshold: f32) -> Self {
self.drag_threshold = threshold;
self
}
pub fn start_dnd(&self, clipboard: &mut dyn Clipboard, bounds: Rectangle) {
let Some(content) = self.drag_content.as_ref().map(|f| f()) else {
return;
};
iced_core::clipboard::start_dnd(
clipboard,
false,
Some(iced_core::clipboard::DndSource::Widget(self.id.clone())),
self.drag_icon.as_ref().map(|f| {
let (icon, state) = f();
(
container(icon)
.width(Length::Fixed(bounds.width))
.height(Length::Fixed(bounds.height))
.into(),
state,
)
}),
Box::new(content),
self.action,
);
}
}
impl<
'a,
Message: 'static,
AppMessage: 'static,
D: iced::clipboard::mime::AsMimeTypes + std::marker::Send + 'static,
> Widget<Message, crate::Theme, crate::Renderer> for DndSource<'a, Message, AppMessage, D>
{
fn children(&self) -> Vec<Tree> {
vec![Tree::new(&self.container)]
}
fn tag(&self) -> iced_core::widget::tree::Tag {
tree::Tag::of::<State>()
}
fn diff(&mut self, tree: &mut Tree) {
tree.children[0].diff(self.container.as_widget_mut());
}
fn state(&self) -> iced_core::widget::tree::State {
tree::State::new(State::new())
}
fn size(&self) -> iced_core::Size<Length> {
self.container.as_widget().size()
}
fn layout(
&self,
tree: &mut Tree,
renderer: &crate::Renderer,
limits: &layout::Limits,
) -> layout::Node {
let state = tree.state.downcast_mut::<State>();
let node = self
.container
.as_widget()
.layout(&mut tree.children[0], renderer, limits);
state.cached_bounds = node.bounds();
node
}
fn operate(
&self,
tree: &mut Tree,
layout: layout::Layout<'_>,
renderer: &crate::Renderer,
operation: &mut dyn iced_core::widget::Operation<
iced_core::widget::OperationOutputWrapper<Message>,
>,
) {
operation.custom((&mut tree.state) as &mut dyn Any, Some(&self.id));
operation.container(Some(&self.id), layout.bounds(), &mut |operation| {
self.container
.as_widget()
.operate(&mut tree.children[0], layout, renderer, operation)
});
}
fn on_event(
&mut self,
tree: &mut Tree,
event: Event,
layout: layout::Layout<'_>,
cursor: mouse::Cursor,
renderer: &crate::Renderer,
clipboard: &mut dyn Clipboard,
shell: &mut Shell<'_, Message>,
viewport: &Rectangle,
) -> event::Status {
let ret = self.container.as_widget_mut().on_event(
&mut tree.children[0],
event.clone(),
layout,
cursor,
renderer,
clipboard,
shell,
viewport,
);
let state = tree.state.downcast_mut::<State>();
match event {
Event::Mouse(mouse_event) => match mouse_event {
mouse::Event::ButtonPressed(mouse::Button::Left) => {
if let Some(position) = cursor.position() {
if !state.hovered {
return ret;
}
state.left_pressed_position = Some(position);
return event::Status::Captured;
}
}
mouse::Event::ButtonReleased(mouse::Button::Left)
if state.left_pressed_position.is_some() =>
{
state.left_pressed_position = None;
return event::Status::Captured;
}
mouse::Event::CursorMoved { .. } => {
if let Some(position) = cursor.position() {
if state.hovered {
if self.drag_content.is_none() {
state.left_pressed_position = None;
return ret;
}
if let Some(left_pressed_position) = state.left_pressed_position {
if position.distance(left_pressed_position) > self.drag_threshold {
self.start_dnd(clipboard, state.cached_bounds);
state.is_dragging = true;
state.left_pressed_position = None;
}
}
if !cursor.is_over(layout.bounds()) {
state.hovered = false;
return ret;
}
} else if cursor.is_over(layout.bounds()) {
state.hovered = true;
}
return event::Status::Captured;
}
}
_ => return ret,
},
Event::Dnd(DndEvent::Source(SourceEvent::Cancelled | SourceEvent::Finished)) => {
if state.is_dragging {
state.is_dragging = false;
return event::Status::Captured;
}
return ret;
}
_ => return ret,
}
ret
}
fn mouse_interaction(
&self,
tree: &Tree,
layout: layout::Layout<'_>,
cursor_position: mouse::Cursor,
viewport: &Rectangle,
renderer: &crate::Renderer,
) -> mouse::Interaction {
let state = tree.state.downcast_ref::<State>();
if state.is_dragging {
return mouse::Interaction::Grabbing;
}
self.container.as_widget().mouse_interaction(
&tree.children[0],
layout,
cursor_position,
viewport,
renderer,
)
}
fn draw(
&self,
tree: &Tree,
renderer: &mut crate::Renderer,
theme: &crate::Theme,
renderer_style: &renderer::Style,
layout: layout::Layout<'_>,
cursor_position: mouse::Cursor,
viewport: &Rectangle,
) {
self.container.as_widget().draw(
&tree.children[0],
renderer,
theme,
renderer_style,
layout,
cursor_position,
viewport,
);
}
fn overlay<'b>(
&'b mut self,
tree: &'b mut Tree,
layout: layout::Layout<'_>,
renderer: &crate::Renderer,
) -> Option<overlay::Element<'b, Message, crate::Theme, crate::Renderer>> {
self.container
.as_widget_mut()
.overlay(&mut tree.children[0], layout, renderer)
}
fn drag_destinations(
&self,
state: &Tree,
layout: layout::Layout<'_>,
renderer: &crate::Renderer,
dnd_rectangles: &mut iced_style::core::clipboard::DndDestinationRectangles,
) {
self.container.as_widget().drag_destinations(
&state.children[0],
layout,
renderer,
dnd_rectangles,
);
}
fn id(&self) -> Option<Id> {
Some(self.id.clone())
}
fn set_id(&mut self, id: Id) {
self.id = id;
}
}
impl<
'a,
Message: 'static,
AppMessage: 'static,
D: iced::clipboard::mime::AsMimeTypes + std::marker::Send + 'static,
> From<DndSource<'a, Message, AppMessage, D>> for Element<'a, Message>
{
fn from(e: DndSource<'a, Message, AppMessage, D>) -> Element<'a, Message> {
Element::new(e)
}
}
#[derive(Debug, Default)]
struct State {
hovered: bool,
left_pressed_position: Option<Point>,
is_dragging: bool,
cached_bounds: Rectangle,
}
impl State {
fn new() -> Self {
Self::default()
}
}