iced-yoda/core/src/widget/text.rs
2026-05-16 08:28:37 -04:00

971 lines
29 KiB
Rust

//! Text widgets display information through writing.
//!
//! # Example
//! ```no_run
//! # mod iced { pub mod widget { pub fn text<T>(t: T) -> iced_core::widget::Text<'static, iced_core::Theme, ()> { unimplemented!() } }
//! # pub use iced_core::color; }
//! # pub type State = ();
//! # pub type Element<'a, Message> = iced_core::Element<'a, Message, iced_core::Theme, ()>;
//! use iced::widget::text;
//! use iced::color;
//!
//! enum Message {
//! // ...
//! }
//!
//! fn view(state: &State) -> Element<'_, Message> {
//! text("Hello, this is iced!")
//! .size(20)
//! .color(color!(0x0000ff))
//! .into()
//! }
//! ```
use crate::alignment;
use crate::layout;
use crate::mouse::{self, click};
use crate::renderer;
use crate::text;
use crate::text::paragraph::{self, Paragraph};
use crate::widget::tree::{self, Tree};
use crate::{
Clipboard, Color, Element, Event, Layout, Length, Pixels, Point, Rectangle,
Shell, Size, Theme, Widget, keyboard, touch,
};
use unicode_segmentation::UnicodeSegmentation;
pub use text::{Alignment, Ellipsize, LineHeight, Shaping, Wrapping};
/// A bunch of text.
///
/// # Example
/// ```no_run
/// # mod iced { pub mod widget { pub fn text<T>(t: T) -> iced_core::widget::Text<'static, iced_core::Theme, ()> { unimplemented!() } }
/// # pub use iced_core::color; }
/// # pub type State = ();
/// # pub type Element<'a, Message> = iced_core::Element<'a, Message, iced_core::Theme, ()>;
/// use iced::widget::text;
/// use iced::color;
///
/// enum Message {
/// // ...
/// }
///
/// fn view(state: &State) -> Element<'_, Message> {
/// text("Hello, this is iced!")
/// .size(20)
/// .color(color!(0x0000ff))
/// .into()
/// }
/// ```
pub struct Text<'a, Theme, Renderer>
where
Theme: Catalog,
Renderer: text::Renderer,
{
id: crate::widget::Id,
fragment: text::Fragment<'a>,
format: Format<Renderer::Font>,
class: Theme::Class<'a>,
selectable: bool,
}
impl<'a, Theme, Renderer> Text<'a, Theme, Renderer>
where
Theme: Catalog,
Renderer: text::Renderer,
{
/// Create a new fragment of [`Text`] with the given contents.
pub fn new(fragment: impl text::IntoFragment<'a>) -> Self {
Text {
id: crate::widget::Id::unique(),
fragment: fragment.into_fragment(),
format: Format::default(),
class: Theme::default(),
selectable: false,
}
}
/// Sets the size of the [`Text`].
pub fn size(mut self, size: impl Into<Pixels>) -> Self {
self.format.size = Some(size.into());
self
}
/// Sets the [`LineHeight`] of the [`Text`].
pub fn line_height(mut self, line_height: impl Into<LineHeight>) -> Self {
self.format.line_height = line_height.into();
self
}
/// Sets the [`Font`] of the [`Text`].
///
/// [`Font`]: crate::text::Renderer::Font
pub fn font(mut self, font: impl Into<Renderer::Font>) -> Self {
self.format.font = Some(font.into());
self
}
/// Sets the [`Font`] of the [`Text`], if `Some`.
///
/// [`Font`]: crate::text::Renderer::Font
pub fn font_maybe(
mut self,
font: Option<impl Into<Renderer::Font>>,
) -> Self {
self.format.font = font.map(Into::into);
self
}
/// Sets the width of the [`Text`] boundaries.
pub fn width(mut self, width: impl Into<Length>) -> Self {
self.format.width = width.into();
self
}
/// Sets the height of the [`Text`] boundaries.
pub fn height(mut self, height: impl Into<Length>) -> Self {
self.format.height = height.into();
self
}
/// Centers the [`Text`], both horizontally and vertically.
pub fn center(self) -> Self {
self.align_x(alignment::Horizontal::Center)
.align_y(alignment::Vertical::Center)
}
/// Sets the [`alignment::Horizontal`] of the [`Text`].
pub fn align_x(mut self, alignment: impl Into<text::Alignment>) -> Self {
self.format.align_x = alignment.into();
self
}
/// Sets the [`alignment::Vertical`] of the [`Text`].
pub fn align_y(
mut self,
alignment: impl Into<alignment::Vertical>,
) -> Self {
self.format.align_y = alignment.into();
self
}
/// Sets the [`Shaping`] strategy of the [`Text`].
pub fn shaping(mut self, shaping: Shaping) -> Self {
self.format.shaping = shaping;
self
}
/// Sets the [`Wrapping`] strategy of the [`Text`].
pub fn wrapping(mut self, wrapping: Wrapping) -> Self {
self.format.wrapping = wrapping;
self
}
// Sets the [`Ellipsize`] strategy of the [`Text`].
pub fn ellipsize(mut self, ellipsize: Ellipsize) -> Self {
self.format.ellipsize = ellipsize;
self
}
/// Sets the style of the [`Text`].
#[must_use]
pub fn style(mut self, style: impl Fn(&Theme) -> Style + 'a) -> Self
where
Theme::Class<'a>: From<StyleFn<'a, Theme>>,
{
self.class = (Box::new(style) as StyleFn<'a, Theme>).into();
self
}
/// Sets the [`Color`] of the [`Text`].
pub fn color(self, color: impl Into<Color>) -> Self
where
Theme::Class<'a>: From<StyleFn<'a, Theme>>,
{
self.color_maybe(Some(color))
}
/// Sets the [`Color`] of the [`Text`], if `Some`.
pub fn color_maybe(self, color: Option<impl Into<Color>>) -> Self
where
Theme::Class<'a>: From<StyleFn<'a, Theme>>,
{
let color = color.map(Into::into);
self.style(move |_theme| Style {
color,
..Style::default()
})
}
/// Makes the [`Text`] selectable. When enabled, the user can click and
/// drag to select text, and copy it with Ctrl+C / Cmd+C.
pub fn selectable(mut self) -> Self {
self.selectable = true;
self
}
/// Sets the style class of the [`Text`].
#[cfg(feature = "advanced")]
#[must_use]
pub fn class(mut self, class: impl Into<Theme::Class<'a>>) -> Self {
self.class = class.into();
self
}
}
/// The internal state of a [`Text`] widget.
pub struct State<P: Paragraph> {
/// The cached paragraph layout.
pub paragraph: paragraph::Plain<P>,
/// Lazily allocated when text is selectable and first interacted with.
selection: Option<Box<SelectionState>>,
}
impl<P: Paragraph> Default for State<P> {
fn default() -> Self {
Self {
paragraph: paragraph::Plain::default(),
selection: None,
}
}
}
impl<P: Paragraph> std::fmt::Debug for State<P> {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("State")
.field("selection", &self.selection)
.finish_non_exhaustive()
}
}
impl<P: Paragraph> std::ops::Deref for State<P> {
type Target = paragraph::Plain<P>;
fn deref(&self) -> &paragraph::Plain<P> {
&self.paragraph
}
}
impl<P: Paragraph> std::ops::DerefMut for State<P> {
fn deref_mut(&mut self) -> &mut paragraph::Plain<P> {
&mut self.paragraph
}
}
#[derive(Debug, Clone, Default)]
struct SelectionState {
anchor: usize,
end: usize,
dragging: bool,
focused: bool,
modifiers: keyboard::Modifiers,
last_click: Option<click::Click>,
}
impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer>
for Text<'_, Theme, Renderer>
where
Theme: Catalog,
Renderer: text::Renderer,
{
fn tag(&self) -> tree::Tag {
tree::Tag::of::<State<Renderer::Paragraph>>()
}
fn state(&self) -> tree::State {
tree::State::new(State::<Renderer::Paragraph>::default())
}
fn size(&self) -> Size<Length> {
Size {
width: self.format.width,
height: self.format.height,
}
}
fn layout(
&mut self,
tree: &mut Tree,
renderer: &Renderer,
limits: &layout::Limits,
) -> layout::Node {
let state = tree.state.downcast_mut::<State<Renderer::Paragraph>>();
layout(
&mut state.paragraph,
renderer,
limits,
&self.fragment,
self.format,
)
}
fn draw(
&self,
tree: &Tree,
renderer: &mut Renderer,
theme: &Theme,
defaults: &renderer::Style,
layout: Layout<'_>,
_cursor_position: mouse::Cursor,
viewport: &Rectangle,
) {
let state = tree.state.downcast_ref::<State<Renderer::Paragraph>>();
let style = theme.style(&self.class);
let bounds = layout.bounds();
let paragraph = state.paragraph.raw();
if let Some(sel) = &state.selection {
let left = sel.anchor.min(sel.end);
let right = sel.anchor.max(sel.end);
let content: &str = self.fragment.as_ref();
if left != right {
let lo_byte = grapheme_to_byte(content, left);
let hi_byte = grapheme_to_byte(content, right);
let anchor = bounds.anchor(
paragraph.min_bounds(),
paragraph.align_x(),
paragraph.align_y(),
);
let rects = paragraph.highlight(
0,
(lo_byte, text::Affinity::After),
(hi_byte, text::Affinity::Before),
);
for r in rects {
renderer.fill_quad(
renderer::Quad {
bounds: Rectangle {
x: anchor.x + r.x,
y: anchor.y + r.y,
width: r.width,
height: r.height,
},
..renderer::Quad::default()
},
style.selected_fill,
);
}
}
}
draw(renderer, defaults, bounds, paragraph, style, viewport);
}
fn update(
&mut self,
tree: &mut Tree,
event: &Event,
layout: Layout<'_>,
cursor: mouse::Cursor,
_renderer: &Renderer,
clipboard: &mut dyn Clipboard,
shell: &mut Shell<'_, Message>,
_viewport: &Rectangle,
) {
if !self.selectable {
return;
}
let state = tree.state.downcast_mut::<State<Renderer::Paragraph>>();
let bounds = layout.bounds();
let content: &str = self.fragment.as_ref();
let grapheme_count = content.graphemes(true).count();
let paragraph = state.paragraph.raw();
match event {
Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
| Event::Touch(touch::Event::FingerPressed { .. }) => {
if let Some(pos) = cursor.position_over(bounds) {
let sel = state.selection.get_or_insert_with(|| {
Box::new(SelectionState::default())
});
let anchor = bounds.anchor(
paragraph.min_bounds(),
paragraph.align_x(),
paragraph.align_y(),
);
let relative =
Point::new(pos.x - anchor.x, pos.y - anchor.y);
let grapheme_pos =
hit_to_grapheme(paragraph, relative, content);
let new_click = click::Click::new(
pos,
mouse::Button::Left,
sel.last_click.take(),
);
match new_click.kind() {
click::Kind::Single => {
if sel.modifiers.shift() {
sel.end = grapheme_pos;
} else {
sel.anchor = grapheme_pos;
sel.end = grapheme_pos;
}
sel.dragging = true;
}
click::Kind::Double => {
sel.anchor =
previous_start_of_word(content, grapheme_pos);
sel.end = next_end_of_word(content, grapheme_pos);
sel.dragging = true;
}
click::Kind::Triple => {
sel.anchor = 0;
sel.end = grapheme_count;
sel.dragging = true;
}
}
sel.last_click = Some(new_click);
sel.focused = true;
shell.capture_event();
} else if let Some(sel) = &mut state.selection {
sel.focused = false;
sel.anchor = 0;
sel.end = 0;
sel.dragging = false;
}
}
Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
| Event::Touch(touch::Event::FingerLifted { .. }) => {
if let Some(sel) = &mut state.selection {
sel.dragging = false;
}
}
Event::Mouse(mouse::Event::CursorMoved { position })
| Event::Touch(touch::Event::FingerMoved { position, .. }) => {
if let Some(sel) = &mut state.selection {
if sel.dragging {
let anchor = bounds.anchor(
paragraph.min_bounds(),
paragraph.align_x(),
paragraph.align_y(),
);
let relative = Point::new(
position.x - anchor.x,
position.y - anchor.y,
);
sel.end = hit_to_grapheme(paragraph, relative, content);
shell.capture_event();
}
}
}
Event::Keyboard(keyboard::Event::KeyPressed {
key,
modifiers,
physical_key,
text: _,
..
}) => {
let focused =
state.selection.as_ref().is_some_and(|s| s.focused);
if !focused {
return;
}
let sel = state.selection.as_mut().unwrap();
if modifiers.command() {
match key.to_latin(*physical_key) {
Some('c') => {
let left = sel.anchor.min(sel.end);
let right = sel.anchor.max(sel.end);
if left != right {
let selected: String = content
.graphemes(true)
.skip(left)
.take(right - left)
.collect();
clipboard.write(
crate::clipboard::Kind::Standard,
selected,
);
}
shell.capture_event();
return;
}
Some('a') => {
sel.anchor = 0;
sel.end = grapheme_count;
shell.capture_event();
return;
}
_ => {}
}
}
match key {
keyboard::Key::Named(keyboard::key::Named::ArrowLeft) => {
let by_word = is_jump_modifier(*modifiers);
if modifiers.shift() {
sel.end = if by_word {
previous_start_of_word(content, sel.end)
} else {
sel.end.saturating_sub(1)
};
} else {
let left = sel.anchor.min(sel.end);
let pos = if by_word {
previous_start_of_word(content, left)
} else {
left.saturating_sub(1)
};
sel.anchor = pos;
sel.end = pos;
}
shell.capture_event();
}
keyboard::Key::Named(keyboard::key::Named::ArrowRight) => {
let by_word = is_jump_modifier(*modifiers);
if modifiers.shift() {
sel.end = if by_word {
next_end_of_word(content, sel.end)
} else {
(sel.end + 1).min(grapheme_count)
};
} else {
let right = sel.anchor.max(sel.end);
let pos = if by_word {
next_end_of_word(content, right)
} else {
(right + 1).min(grapheme_count)
};
sel.anchor = pos;
sel.end = pos;
}
shell.capture_event();
}
keyboard::Key::Named(keyboard::key::Named::Home) => {
if modifiers.shift() {
sel.end = 0;
} else {
sel.anchor = 0;
sel.end = 0;
}
shell.capture_event();
}
keyboard::Key::Named(keyboard::key::Named::End) => {
if modifiers.shift() {
sel.end = grapheme_count;
} else {
sel.anchor = grapheme_count;
sel.end = grapheme_count;
}
shell.capture_event();
}
_ => {}
}
}
Event::Keyboard(keyboard::Event::ModifiersChanged(modifiers)) => {
if let Some(sel) = &mut state.selection {
sel.modifiers = *modifiers;
}
}
_ => {}
}
}
fn mouse_interaction(
&self,
_tree: &Tree,
layout: Layout<'_>,
cursor: mouse::Cursor,
_viewport: &Rectangle,
_renderer: &Renderer,
) -> mouse::Interaction {
if self.selectable && cursor.is_over(layout.bounds()) {
mouse::Interaction::Text
} else {
mouse::Interaction::None
}
}
fn operate(
&mut self,
_tree: &mut Tree,
layout: Layout<'_>,
_renderer: &Renderer,
operation: &mut dyn super::Operation,
) {
operation.text(None, layout.bounds(), &self.fragment);
}
#[cfg(feature = "a11y")]
fn a11y_nodes(
&self,
layout: Layout<'_>,
_state: &Tree,
_: mouse::Cursor,
) -> iced_accessibility::A11yTree {
use iced_accessibility::{
A11yTree,
accesskit::{Live, Node, Rect, Role},
};
let Rectangle {
x,
y,
width,
height,
} = layout.bounds();
let bounds = Rect::new(
x as f64,
y as f64,
(x + width) as f64,
(y + height) as f64,
);
let mut node = Node::new(Role::Paragraph);
// TODO is the name likely different from the content?
node.set_label(self.fragment.to_string().into_boxed_str());
node.set_bounds(bounds);
// TODO make this configurable
node.set_live(Live::Polite);
A11yTree::leaf(node, self.id.clone())
}
fn id(&self) -> Option<crate::widget::Id> {
Some(self.id.clone())
}
fn set_id(&mut self, id: crate::widget::Id) {
self.id = id;
}
}
/// The format of some [`Text`].
///
/// Check out the methods of the [`Text`] widget
/// to learn more about each field.
#[derive(Debug, Clone, Copy)]
#[allow(missing_docs)]
pub struct Format<Font> {
pub width: Length,
pub height: Length,
pub size: Option<Pixels>,
pub font: Option<Font>,
pub line_height: LineHeight,
pub align_x: text::Alignment,
pub align_y: alignment::Vertical,
pub shaping: Shaping,
pub wrapping: Wrapping,
pub ellipsize: Ellipsize,
}
impl<Font> Default for Format<Font> {
fn default() -> Self {
Self {
size: None,
line_height: LineHeight::default(),
font: None,
width: Length::Shrink,
height: Length::Shrink,
align_x: text::Alignment::Default,
align_y: alignment::Vertical::Top,
shaping: Shaping::default(),
wrapping: Wrapping::default(),
ellipsize: Ellipsize::default(),
}
}
}
/// Produces the [`layout::Node`] of a [`Text`] widget.
pub fn layout<Renderer>(
paragraph: &mut paragraph::Plain<Renderer::Paragraph>,
renderer: &Renderer,
limits: &layout::Limits,
content: &str,
format: Format<Renderer::Font>,
) -> layout::Node
where
Renderer: text::Renderer,
{
layout::sized(limits, format.width, format.height, |limits| {
let bounds = limits.max();
let size = format.size.unwrap_or_else(|| renderer.default_size());
let font = format.font.unwrap_or_else(|| renderer.default_font());
let _ = paragraph.update(text::Text {
content,
bounds,
size,
line_height: format.line_height,
font,
align_x: format.align_x,
align_y: format.align_y,
shaping: format.shaping,
wrapping: format.wrapping,
ellipsize: format.ellipsize,
});
paragraph.min_bounds()
})
}
/// Draws text using the same logic as the [`Text`] widget.
pub fn draw<Renderer>(
renderer: &mut Renderer,
style: &renderer::Style,
bounds: Rectangle,
paragraph: &Renderer::Paragraph,
appearance: Style,
viewport: &Rectangle,
) where
Renderer: text::Renderer,
{
let anchor = bounds.anchor(
paragraph.min_bounds(),
paragraph.align_x(),
paragraph.align_y(),
);
renderer.fill_paragraph(
paragraph,
anchor,
appearance.color.unwrap_or(style.text_color),
*viewport,
);
}
impl<'a, Message, Theme, Renderer> From<Text<'a, Theme, Renderer>>
for Element<'a, Message, Theme, Renderer>
where
Theme: Catalog + 'a,
Renderer: text::Renderer + 'a,
{
fn from(
text: Text<'a, Theme, Renderer>,
) -> Element<'a, Message, Theme, Renderer> {
Element::new(text)
}
}
// impl<'a, Theme, Renderer> Clone for Text<'a, Theme, Renderer>
// where
// Renderer: text::Renderer,
// {
// fn clone(&self) -> Self {
// Self {
// id: self.id.clone(),
// content: self.content.clone(),
// size: self.size,
// line_height: self.line_height,
// width: self.width,
// height: self.height,
// horizontal_alignment: self.horizontal_alignment,
// vertical_alignment: self.vertical_alignment,
// font: self.font,
// style: self.style,
// shaping: self.shaping,
// wrap: self.wrap,
// }
// }
// }
// TODO(POP): Clone no longer can be implemented because of style being a Box(style)
impl<'a, Theme, Renderer> From<&'a str> for Text<'a, Theme, Renderer>
where
Theme: Catalog + 'a,
Renderer: text::Renderer,
{
fn from(content: &'a str) -> Self {
Self::new(content)
}
}
impl<'a, Message, Theme, Renderer> From<&'a str>
for Element<'a, Message, Theme, Renderer>
where
Theme: Catalog + 'a,
Renderer: text::Renderer + 'a,
{
fn from(content: &'a str) -> Self {
Text::from(content).into()
}
}
/// The appearance of some text.
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Style {
/// The [`Color`] of the text.
///
/// The default, `None`, means using the inherited color.
pub color: Option<Color>,
/// The fill [`Color`] of the selection highlight.
pub selected_fill: Color,
}
impl Default for Style {
fn default() -> Self {
Self {
color: None,
selected_fill: DEFAULT_SELECTION_COLOR,
}
}
}
/// The theme catalog of a [`Text`].
pub trait Catalog: Sized {
/// The item class of this [`Catalog`].
type Class<'a>;
/// The default class produced by this [`Catalog`].
fn default<'a>() -> Self::Class<'a>;
/// The [`Style`] of a class with the given status.
fn style(&self, item: &Self::Class<'_>) -> Style;
}
/// A styling function for a [`Text`].
///
/// This is just a boxed closure: `Fn(&Theme, Status) -> Style`.
pub type StyleFn<'a, Theme> = Box<dyn Fn(&Theme) -> Style + 'a>;
impl Catalog for Theme {
type Class<'a> = StyleFn<'a, Self>;
fn default<'a>() -> Self::Class<'a> {
Box::new(|_theme| Style::default())
}
fn style(&self, class: &Self::Class<'_>) -> Style {
class(self)
}
}
/// The default text styling; color is inherited.
pub fn default(_theme: &Theme) -> Style {
Style::default()
}
/// Text with the default base color.
pub fn base(theme: &Theme) -> Style {
Style {
color: Some(theme.palette().text),
..Style::default()
}
}
/// Text conveying some important information, like an action.
pub fn primary(theme: &Theme) -> Style {
Style {
color: Some(theme.palette().primary),
..Style::default()
}
}
/// Text conveying some secondary information, like a footnote.
pub fn secondary(theme: &Theme) -> Style {
Style {
color: Some(theme.extended_palette().secondary.base.color),
..Style::default()
}
}
/// Text conveying some positive information, like a successful event.
pub fn success(theme: &Theme) -> Style {
Style {
color: Some(theme.palette().success),
..Style::default()
}
}
/// Text conveying some mildly negative information, like a warning.
pub fn warning(theme: &Theme) -> Style {
Style {
color: Some(theme.palette().warning),
..Style::default()
}
}
/// Text conveying some negative information, like an error.
pub fn danger(theme: &Theme) -> Style {
Style {
color: Some(theme.palette().danger),
..Style::default()
}
}
const DEFAULT_SELECTION_COLOR: Color = Color {
r: 0.0,
g: 0.47,
b: 0.84,
a: 0.3,
};
fn grapheme_to_byte(content: &str, grapheme_index: usize) -> usize {
content
.graphemes(true)
.take(grapheme_index)
.map(|g| g.len())
.sum()
}
fn hit_to_grapheme<P: Paragraph>(
paragraph: &P,
point: Point,
content: &str,
) -> usize {
match paragraph.hit_test(point) {
Some(hit) => {
let byte_offset = hit.cursor().min(content.len());
content[..byte_offset].graphemes(true).count()
}
None => content.graphemes(true).count(),
}
}
fn previous_start_of_word(content: &str, grapheme_index: usize) -> usize {
let graphemes: Vec<&str> = content.graphemes(true).collect();
let clamped = grapheme_index.min(graphemes.len());
let before: String = graphemes[..clamped].concat();
UnicodeSegmentation::split_word_bound_indices(&*before)
.filter(|(_, word)| !word.trim_start().is_empty())
.next_back()
.map_or(0, |(i, prev_word)| {
clamped
- prev_word.graphemes(true).count()
- before[i + prev_word.len()..].graphemes(true).count()
})
}
fn next_end_of_word(content: &str, grapheme_index: usize) -> usize {
let graphemes: Vec<&str> = content.graphemes(true).collect();
let clamped = grapheme_index.min(graphemes.len());
let after: String = graphemes[clamped..].concat();
UnicodeSegmentation::split_word_bound_indices(&*after)
.find(|(_, word)| !word.trim_start().is_empty())
.map_or(graphemes.len(), |(i, next_word)| {
clamped
+ next_word.graphemes(true).count()
+ after[..i].graphemes(true).count()
})
}
fn is_jump_modifier(modifiers: keyboard::Modifiers) -> bool {
if cfg!(target_os = "macos") {
modifiers.alt()
} else {
modifiers.control()
}
}