iced/native/src/widget/pick_list.rs
2022-11-29 11:52:52 +01:00

655 lines
18 KiB
Rust

//! Display a dropdown list of selectable values.
use crate::alignment;
use crate::event::{self, Event};
use crate::keyboard;
use crate::layout;
use crate::mouse;
use crate::overlay;
use crate::overlay::menu::{self, Menu};
use crate::renderer;
use crate::text::{self, Text};
use crate::touch;
use crate::widget::container;
use crate::widget::scrollable;
use crate::widget::tree::{self, Tree};
use crate::{
Clipboard, Element, Layout, Length, Padding, Point, Rectangle, Shell, Size,
Widget,
};
use std::borrow::Cow;
pub use iced_style::pick_list::{Appearance, StyleSheet};
/// The content to the right side of the [`PickList`].
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum AccessoryContent<Renderer>
where
Renderer: text::Renderer,
{
/// Default accessory content.
Default {
/// Font size of the content.
size: Option<u16>,
},
/// Custom accessory content.
Custom {
/// Font which will be used in the accessory content.
font: Renderer::Font,
/// Content which will be shown.
content: String,
/// Font size of the content.
size: Option<u16>,
},
/// No accessory content will be shown.
None,
}
impl<Renderer> Default for AccessoryContent<Renderer>
where
Renderer: text::Renderer,
{
fn default() -> Self {
Self::Default { size: None }
}
}
impl<Renderer> AccessoryContent<Renderer>
where
Renderer: text::Renderer,
{
fn content(&self) -> Option<(Renderer::Font, String, Option<u16>)> {
match self {
AccessoryContent::Default { size } => Some((
Renderer::ICON_FONT,
Renderer::ARROW_DOWN_ICON.to_string(),
*size,
)),
AccessoryContent::Custom {
font,
content,
size,
} => Some((font.clone(), content.clone(), *size)),
AccessoryContent::None => None,
}
}
}
/// A widget for selecting a single value from a list of options.
#[allow(missing_debug_implementations)]
pub struct PickList<'a, T, Message, Renderer>
where
[T]: ToOwned<Owned = Vec<T>>,
Renderer: text::Renderer,
Renderer::Theme: StyleSheet,
{
on_selected: Box<dyn Fn(T) -> Message + 'a>,
options: Cow<'a, [T]>,
placeholder: Option<String>,
selected: Option<T>,
width: Length,
padding: Padding,
text_size: Option<u16>,
font: Renderer::Font,
accessory_content: AccessoryContent<Renderer>,
style: <Renderer::Theme as StyleSheet>::Style,
}
impl<'a, T: 'a, Message, Renderer> PickList<'a, T, Message, Renderer>
where
T: ToString + Eq,
[T]: ToOwned<Owned = Vec<T>>,
Renderer: text::Renderer,
Renderer::Theme: StyleSheet
+ scrollable::StyleSheet
+ menu::StyleSheet
+ container::StyleSheet,
<Renderer::Theme as menu::StyleSheet>::Style:
From<<Renderer::Theme as StyleSheet>::Style>,
{
/// The default padding of a [`PickList`].
pub const DEFAULT_PADDING: Padding = Padding::new(5);
/// Creates a new [`PickList`] with the given list of options, the current
/// selected value, and the message to produce when an option is selected.
pub fn new(
options: impl Into<Cow<'a, [T]>>,
selected: Option<T>,
on_selected: impl Fn(T) -> Message + 'a,
) -> Self {
Self {
on_selected: Box::new(on_selected),
options: options.into(),
placeholder: None,
selected,
width: Length::Shrink,
padding: Self::DEFAULT_PADDING,
text_size: None,
font: Default::default(),
accessory_content: Default::default(),
style: Default::default(),
}
}
/// Sets the placeholder of the [`PickList`].
pub fn placeholder(mut self, placeholder: impl Into<String>) -> Self {
self.placeholder = Some(placeholder.into());
self
}
/// Sets the width of the [`PickList`].
pub fn width(mut self, width: Length) -> Self {
self.width = width;
self
}
/// Sets the [`Padding`] of the [`PickList`].
pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self {
self.padding = padding.into();
self
}
/// Sets the text size of the [`PickList`].
pub fn text_size(mut self, size: u16) -> Self {
self.text_size = Some(size);
self
}
/// Sets the font of the [`PickList`].
pub fn font(mut self, font: Renderer::Font) -> Self {
self.font = font;
self
}
/// Sets the [`AccessoryContent`] of the [`PickList`].
pub fn accessory_content(
mut self,
accessory_content: AccessoryContent<Renderer>,
) -> Self {
self.accessory_content = accessory_content;
self
}
/// Sets the style of the [`PickList`].
pub fn style(
mut self,
style: impl Into<<Renderer::Theme as StyleSheet>::Style>,
) -> Self {
self.style = style.into();
self
}
}
impl<'a, T: 'a, Message, Renderer> Widget<Message, Renderer>
for PickList<'a, T, Message, Renderer>
where
T: Clone + ToString + Eq + 'static,
[T]: ToOwned<Owned = Vec<T>>,
Message: 'a,
Renderer: text::Renderer + 'a,
Renderer::Theme: StyleSheet
+ scrollable::StyleSheet
+ menu::StyleSheet
+ container::StyleSheet,
<Renderer::Theme as menu::StyleSheet>::Style:
From<<Renderer::Theme as StyleSheet>::Style>,
{
fn tag(&self) -> tree::Tag {
tree::Tag::of::<State<T>>()
}
fn state(&self) -> tree::State {
tree::State::new(State::<T>::new())
}
fn width(&self) -> Length {
self.width
}
fn height(&self) -> Length {
Length::Shrink
}
fn layout(
&self,
renderer: &Renderer,
limits: &layout::Limits,
) -> layout::Node {
layout(
renderer,
limits,
self.width,
self.padding,
self.text_size,
&self.font,
self.placeholder.as_deref(),
&self.options,
)
}
fn on_event(
&mut self,
tree: &mut Tree,
event: Event,
layout: Layout<'_>,
cursor_position: Point,
_renderer: &Renderer,
_clipboard: &mut dyn Clipboard,
shell: &mut Shell<'_, Message>,
) -> event::Status {
update(
event,
layout,
cursor_position,
shell,
self.on_selected.as_ref(),
self.selected.as_ref(),
&self.options,
|| tree.state.downcast_mut::<State<T>>(),
)
}
fn mouse_interaction(
&self,
_tree: &Tree,
layout: Layout<'_>,
cursor_position: Point,
_viewport: &Rectangle,
_renderer: &Renderer,
) -> mouse::Interaction {
mouse_interaction(layout, cursor_position)
}
fn draw(
&self,
_tree: &Tree,
renderer: &mut Renderer,
theme: &Renderer::Theme,
_style: &renderer::Style,
layout: Layout<'_>,
cursor_position: Point,
_viewport: &Rectangle,
) {
draw(
renderer,
theme,
layout,
cursor_position,
self.padding,
self.text_size,
&self.font,
self.placeholder.as_deref(),
self.selected.as_ref(),
&self.accessory_content,
&self.style,
)
}
fn overlay<'b>(
&'b self,
tree: &'b mut Tree,
layout: Layout<'_>,
_renderer: &Renderer,
) -> Option<overlay::Element<'b, Message, Renderer>> {
let state = tree.state.downcast_mut::<State<T>>();
overlay(
layout,
state,
self.padding,
self.text_size,
self.font.clone(),
&self.options,
self.style.clone(),
)
}
}
impl<'a, T: 'a, Message, Renderer> From<PickList<'a, T, Message, Renderer>>
for Element<'a, Message, Renderer>
where
T: Clone + ToString + Eq + 'static,
[T]: ToOwned<Owned = Vec<T>>,
Message: 'a,
Renderer: text::Renderer + 'a,
Renderer::Theme: StyleSheet
+ scrollable::StyleSheet
+ menu::StyleSheet
+ container::StyleSheet,
<Renderer::Theme as menu::StyleSheet>::Style:
From<<Renderer::Theme as StyleSheet>::Style>,
{
fn from(pick_list: PickList<'a, T, Message, Renderer>) -> Self {
Self::new(pick_list)
}
}
/// The local state of a [`PickList`].
#[derive(Debug)]
pub struct State<T> {
menu: menu::State,
keyboard_modifiers: keyboard::Modifiers,
is_open: bool,
hovered_option: Option<usize>,
last_selection: Option<T>,
}
impl<T> State<T> {
/// Creates a new [`State`] for a [`PickList`].
pub fn new() -> Self {
Self {
menu: menu::State::default(),
keyboard_modifiers: keyboard::Modifiers::default(),
is_open: bool::default(),
hovered_option: Option::default(),
last_selection: Option::default(),
}
}
}
impl<T> Default for State<T> {
fn default() -> Self {
Self::new()
}
}
/// Computes the layout of a [`PickList`].
pub fn layout<Renderer, T>(
renderer: &Renderer,
limits: &layout::Limits,
width: Length,
padding: Padding,
text_size: Option<u16>,
font: &Renderer::Font,
placeholder: Option<&str>,
options: &[T],
) -> layout::Node
where
Renderer: text::Renderer,
T: ToString,
{
use std::f32;
let limits = limits.width(width).height(Length::Shrink).pad(padding);
let text_size = text_size.unwrap_or_else(|| renderer.default_size());
let max_width = match width {
Length::Shrink => {
let measure = |label: &str| -> u32 {
let (width, _) = renderer.measure(
label,
text_size,
font.clone(),
Size::new(f32::INFINITY, f32::INFINITY),
);
width.round() as u32
};
let labels = options.iter().map(ToString::to_string);
let labels_width =
labels.map(|label| measure(&label)).max().unwrap_or(100);
let placeholder_width = placeholder.map(measure).unwrap_or(100);
labels_width.max(placeholder_width)
}
_ => 0,
};
let size = {
let intrinsic = Size::new(
max_width as f32 + f32::from(text_size) + f32::from(padding.left),
f32::from(text_size),
);
limits.resolve(intrinsic).pad(padding)
};
layout::Node::new(size)
}
/// Processes an [`Event`] and updates the [`State`] of a [`PickList`]
/// accordingly.
pub fn update<'a, T, Message>(
event: Event,
layout: Layout<'_>,
cursor_position: Point,
shell: &mut Shell<'_, Message>,
on_selected: &dyn Fn(T) -> Message,
selected: Option<&T>,
options: &[T],
state: impl FnOnce() -> &'a mut State<T>,
) -> event::Status
where
T: PartialEq + Clone + 'a,
{
match event {
Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
| Event::Touch(touch::Event::FingerPressed { .. }) => {
let state = state();
let event_status = if state.is_open {
// Event wasn't processed by overlay, so cursor was clicked either outside it's
// bounds or on the drop-down, either way we close the overlay.
state.is_open = false;
event::Status::Captured
} else if layout.bounds().contains(cursor_position) {
state.is_open = true;
state.hovered_option =
options.iter().position(|option| Some(option) == selected);
event::Status::Captured
} else {
event::Status::Ignored
};
if let Some(last_selection) = state.last_selection.take() {
shell.publish((on_selected)(last_selection));
state.is_open = false;
event::Status::Captured
} else {
event_status
}
}
Event::Mouse(mouse::Event::WheelScrolled {
delta: mouse::ScrollDelta::Lines { y, .. },
}) => {
let state = state();
if state.keyboard_modifiers.command()
&& layout.bounds().contains(cursor_position)
&& !state.is_open
{
fn find_next<'a, T: PartialEq>(
selected: &'a T,
mut options: impl Iterator<Item = &'a T>,
) -> Option<&'a T> {
let _ = options.find(|&option| option == selected);
options.next()
}
let next_option = if y < 0.0 {
if let Some(selected) = selected {
find_next(selected, options.iter())
} else {
options.first()
}
} else if y > 0.0 {
if let Some(selected) = selected {
find_next(selected, options.iter().rev())
} else {
options.last()
}
} else {
None
};
if let Some(next_option) = next_option {
shell.publish((on_selected)(next_option.clone()));
}
event::Status::Captured
} else {
event::Status::Ignored
}
}
Event::Keyboard(keyboard::Event::ModifiersChanged(modifiers)) => {
let state = state();
state.keyboard_modifiers = modifiers;
event::Status::Ignored
}
_ => event::Status::Ignored,
}
}
/// Returns the current [`mouse::Interaction`] of a [`PickList`].
pub fn mouse_interaction(
layout: Layout<'_>,
cursor_position: Point,
) -> mouse::Interaction {
let bounds = layout.bounds();
let is_mouse_over = bounds.contains(cursor_position);
if is_mouse_over {
mouse::Interaction::Pointer
} else {
mouse::Interaction::default()
}
}
/// Returns the current overlay of a [`PickList`].
pub fn overlay<'a, T, Message, Renderer>(
layout: Layout<'_>,
state: &'a mut State<T>,
padding: Padding,
text_size: Option<u16>,
font: Renderer::Font,
options: &'a [T],
style: <Renderer::Theme as StyleSheet>::Style,
) -> Option<overlay::Element<'a, Message, Renderer>>
where
T: Clone + ToString,
Message: 'a,
Renderer: text::Renderer + 'a,
Renderer::Theme: StyleSheet
+ scrollable::StyleSheet
+ menu::StyleSheet
+ container::StyleSheet,
<Renderer::Theme as menu::StyleSheet>::Style:
From<<Renderer::Theme as StyleSheet>::Style>,
{
if state.is_open {
let bounds = layout.bounds();
let mut menu = Menu::new(
&mut state.menu,
options,
&mut state.hovered_option,
&mut state.last_selection,
)
.width(bounds.width.round() as u16)
.padding(padding)
.font(font)
.style(style);
if let Some(text_size) = text_size {
menu = menu.text_size(text_size);
}
Some(menu.overlay(layout.position(), bounds.height))
} else {
None
}
}
/// Draws a [`PickList`].
pub fn draw<T, Renderer>(
renderer: &mut Renderer,
theme: &Renderer::Theme,
layout: Layout<'_>,
cursor_position: Point,
padding: Padding,
text_size: Option<u16>,
font: &Renderer::Font,
placeholder: Option<&str>,
selected: Option<&T>,
accessory_content: &AccessoryContent<Renderer>,
style: &<Renderer::Theme as StyleSheet>::Style,
) where
Renderer: text::Renderer,
Renderer::Theme: StyleSheet,
T: ToString,
{
let bounds = layout.bounds();
let is_mouse_over = bounds.contains(cursor_position);
let is_selected = selected.is_some();
let style = if is_mouse_over {
theme.hovered(style)
} else {
theme.active(style)
};
renderer.fill_quad(
renderer::Quad {
bounds,
border_color: style.border_color,
border_width: style.border_width,
border_radius: style.border_radius,
},
style.background,
);
if let Some((font, content, size)) = accessory_content.content() {
let size = f32::from(size.unwrap_or_else(|| renderer.default_size()));
renderer.fill_text(Text {
content: &content,
size,
font,
color: style.text_color,
bounds: Rectangle {
x: bounds.x + bounds.width - f32::from(padding.horizontal()),
y: bounds.center_y() - size / 2.0,
height: size,
..bounds
},
horizontal_alignment: alignment::Horizontal::Right,
vertical_alignment: alignment::Vertical::Top,
});
}
let label = selected.map(ToString::to_string);
if let Some(label) = label.as_deref().or(placeholder) {
let text_size =
f32::from(text_size.unwrap_or_else(|| renderer.default_size()));
renderer.fill_text(Text {
content: label,
size: text_size,
font: font.clone(),
color: if is_selected {
style.text_color
} else {
style.placeholder_color
},
bounds: Rectangle {
x: bounds.x + f32::from(padding.left),
y: bounds.center_y() - text_size / 2.0,
width: bounds.width - f32::from(padding.horizontal()),
height: text_size,
},
horizontal_alignment: alignment::Horizontal::Left,
vertical_alignment: alignment::Vertical::Top,
});
}
}