ZIm/crates/gpui/src/elements/text.rs
2023-09-11 09:00:59 -06:00

438 lines
15 KiB
Rust

use crate::{
color::Color,
fonts::{HighlightStyle, TextStyle},
geometry::{
rect::RectF,
vector::{vec2f, Vector2F},
},
json::{ToJson, Value},
text_layout::{Line, RunStyle, ShapedBoundary},
Element, FontCache, SizeConstraint, TextLayoutCache, ViewContext, WindowContext,
};
use log::warn;
use serde_json::json;
use std::{borrow::Cow, ops::Range, sync::Arc};
pub struct Text {
text: Cow<'static, str>,
style: TextStyle,
soft_wrap: bool,
highlights: Option<Box<[(Range<usize>, HighlightStyle)]>>,
custom_runs: Option<(
Box<[Range<usize>]>,
Box<dyn FnMut(usize, RectF, &mut WindowContext)>,
)>,
}
pub struct LayoutState {
shaped_lines: Vec<Line>,
wrap_boundaries: Vec<Vec<ShapedBoundary>>,
line_height: f32,
}
impl Text {
pub fn new<I: Into<Cow<'static, str>>>(text: I, style: TextStyle) -> Self {
Self {
text: text.into(),
style,
soft_wrap: true,
highlights: None,
custom_runs: None,
}
}
pub fn with_default_color(mut self, color: Color) -> Self {
self.style.color = color;
self
}
pub fn with_highlights(
mut self,
runs: impl Into<Box<[(Range<usize>, HighlightStyle)]>>,
) -> Self {
self.highlights = Some(runs.into());
self
}
pub fn with_custom_runs(
mut self,
runs: impl Into<Box<[Range<usize>]>>,
callback: impl 'static + FnMut(usize, RectF, &mut WindowContext),
) -> Self {
self.custom_runs = Some((runs.into(), Box::new(callback)));
self
}
pub fn with_soft_wrap(mut self, soft_wrap: bool) -> Self {
self.soft_wrap = soft_wrap;
self
}
}
impl<V: 'static> Element<V> for Text {
type LayoutState = LayoutState;
type PaintState = ();
fn layout(
&mut self,
constraint: SizeConstraint,
_: &mut V,
cx: &mut ViewContext<V>,
) -> (Vector2F, Self::LayoutState) {
// Convert the string and highlight ranges into an iterator of highlighted chunks.
let mut offset = 0;
let mut highlight_ranges = self
.highlights
.as_ref()
.map_or(Default::default(), AsRef::as_ref)
.iter()
.peekable();
let chunks = std::iter::from_fn(|| {
let result;
if let Some((range, highlight_style)) = highlight_ranges.peek() {
if offset < range.start {
result = Some((&self.text[offset..range.start], None));
offset = range.start;
} else if range.end <= self.text.len() {
result = Some((&self.text[range.clone()], Some(*highlight_style)));
highlight_ranges.next();
offset = range.end;
} else {
warn!(
"Highlight out of text range. Text len: {}, Highlight range: {}..{}",
self.text.len(),
range.start,
range.end
);
result = None;
}
} else if offset < self.text.len() {
result = Some((&self.text[offset..], None));
offset = self.text.len();
} else {
result = None;
}
result
});
// Perform shaping on these highlighted chunks
let shaped_lines = layout_highlighted_chunks(
chunks,
&self.style,
cx.text_layout_cache(),
&cx.font_cache,
usize::MAX,
self.text.matches('\n').count() + 1,
);
// If line wrapping is enabled, wrap each of the shaped lines.
let font_id = self.style.font_id;
let mut line_count = 0;
let mut max_line_width = 0_f32;
let mut wrap_boundaries = Vec::new();
let mut wrapper = cx.font_cache.line_wrapper(font_id, self.style.font_size);
for (line, shaped_line) in self.text.split('\n').zip(&shaped_lines) {
if self.soft_wrap {
let boundaries = wrapper
.wrap_shaped_line(line, shaped_line, constraint.max.x())
.collect::<Vec<_>>();
line_count += boundaries.len() + 1;
wrap_boundaries.push(boundaries);
} else {
line_count += 1;
}
max_line_width = max_line_width.max(shaped_line.width());
}
let line_height = cx.font_cache.line_height(self.style.font_size);
let size = vec2f(
max_line_width
.ceil()
.max(constraint.min.x())
.min(constraint.max.x()),
(line_height * line_count as f32).ceil(),
);
(
size,
LayoutState {
shaped_lines,
wrap_boundaries,
line_height,
},
)
}
fn paint(
&mut self,
bounds: RectF,
visible_bounds: RectF,
layout: &mut Self::LayoutState,
_: &mut V,
cx: &mut ViewContext<V>,
) -> Self::PaintState {
let mut origin = bounds.origin();
let empty = Vec::new();
let mut callback = |_, _, _: &mut WindowContext| {};
let mouse_runs;
let custom_run_callback;
if let Some((runs, build_region)) = &mut self.custom_runs {
mouse_runs = runs.iter();
custom_run_callback = build_region.as_mut();
} else {
mouse_runs = [].iter();
custom_run_callback = &mut callback;
}
let mut custom_runs = mouse_runs.enumerate().peekable();
let mut offset = 0;
for (ix, line) in layout.shaped_lines.iter().enumerate() {
let wrap_boundaries = layout.wrap_boundaries.get(ix).unwrap_or(&empty);
let boundaries = RectF::new(
origin,
vec2f(
bounds.width(),
(wrap_boundaries.len() + 1) as f32 * layout.line_height,
),
);
if boundaries.intersects(visible_bounds) {
if self.soft_wrap {
line.paint_wrapped(
origin,
visible_bounds,
layout.line_height,
wrap_boundaries,
cx,
);
} else {
line.paint(origin, visible_bounds, layout.line_height, cx);
}
}
// Paint any custom runs that intersect this line.
let end_offset = offset + line.len();
if let Some((custom_run_ix, custom_run_range)) = custom_runs.peek().cloned() {
if custom_run_range.start < end_offset {
let mut current_custom_run = None;
if custom_run_range.start <= offset {
current_custom_run = Some((custom_run_ix, custom_run_range.end, origin));
}
let mut glyph_origin = origin;
let mut prev_position = 0.;
let mut wrap_boundaries = wrap_boundaries.iter().copied().peekable();
for (run_ix, glyph_ix, glyph) in
line.runs().iter().enumerate().flat_map(|(run_ix, run)| {
run.glyphs()
.iter()
.enumerate()
.map(move |(ix, glyph)| (run_ix, ix, glyph))
})
{
glyph_origin.set_x(glyph_origin.x() + glyph.position.x() - prev_position);
prev_position = glyph.position.x();
// If we've reached a soft wrap position, move down one line. If there
// is a custom run in-progress, paint it.
if wrap_boundaries
.peek()
.map_or(false, |b| b.run_ix == run_ix && b.glyph_ix == glyph_ix)
{
if let Some((run_ix, _, run_origin)) = &mut current_custom_run {
let bounds = RectF::from_points(
*run_origin,
glyph_origin + vec2f(0., layout.line_height),
);
custom_run_callback(*run_ix, bounds, cx);
*run_origin =
vec2f(origin.x(), glyph_origin.y() + layout.line_height);
}
wrap_boundaries.next();
glyph_origin = vec2f(origin.x(), glyph_origin.y() + layout.line_height);
}
// If we've reached the end of the current custom run, paint it.
if let Some((run_ix, run_end_offset, run_origin)) = current_custom_run {
if offset + glyph.index == run_end_offset {
current_custom_run.take();
let bounds = RectF::from_points(
run_origin,
glyph_origin + vec2f(0., layout.line_height),
);
custom_run_callback(run_ix, bounds, cx);
custom_runs.next();
}
if let Some((_, run_range)) = custom_runs.peek() {
if run_range.start >= end_offset {
break;
}
if run_range.start == offset + glyph.index {
current_custom_run =
Some((run_ix, run_range.end, glyph_origin));
}
}
}
// If we've reached the start of a new custom run, start tracking it.
if let Some((run_ix, run_range)) = custom_runs.peek() {
if offset + glyph.index == run_range.start {
current_custom_run = Some((*run_ix, run_range.end, glyph_origin));
}
}
}
// If a custom run extends beyond the end of the line, paint it.
if let Some((run_ix, run_end_offset, run_origin)) = current_custom_run {
let line_end = glyph_origin + vec2f(line.width() - prev_position, 0.);
let bounds = RectF::from_points(
run_origin,
line_end + vec2f(0., layout.line_height),
);
custom_run_callback(run_ix, bounds, cx);
if end_offset == run_end_offset {
custom_runs.next();
}
}
}
}
offset = end_offset + 1;
origin.set_y(boundaries.max_y());
}
}
fn rect_for_text_range(
&self,
_: Range<usize>,
_: RectF,
_: RectF,
_: &Self::LayoutState,
_: &Self::PaintState,
_: &V,
_: &ViewContext<V>,
) -> Option<RectF> {
None
}
fn debug(
&self,
bounds: RectF,
_: &Self::LayoutState,
_: &Self::PaintState,
_: &V,
_: &ViewContext<V>,
) -> Value {
json!({
"type": "Text",
"bounds": bounds.to_json(),
"text": &self.text,
"style": self.style.to_json(),
})
}
}
/// Perform text layout on a series of highlighted chunks of text.
pub fn layout_highlighted_chunks<'a>(
chunks: impl Iterator<Item = (&'a str, Option<HighlightStyle>)>,
text_style: &TextStyle,
text_layout_cache: &TextLayoutCache,
font_cache: &Arc<FontCache>,
max_line_len: usize,
max_line_count: usize,
) -> Vec<Line> {
let mut layouts = Vec::with_capacity(max_line_count);
let mut line = String::new();
let mut styles = Vec::new();
let mut row = 0;
let mut line_exceeded_max_len = false;
for (chunk, highlight_style) in chunks.chain([("\n", Default::default())]) {
for (ix, mut line_chunk) in chunk.split('\n').enumerate() {
if ix > 0 {
layouts.push(text_layout_cache.layout_str(&line, text_style.font_size, &styles));
line.clear();
styles.clear();
row += 1;
line_exceeded_max_len = false;
if row == max_line_count {
return layouts;
}
}
if !line_chunk.is_empty() && !line_exceeded_max_len {
let text_style = if let Some(style) = highlight_style {
text_style
.clone()
.highlight(style, font_cache)
.map(Cow::Owned)
.unwrap_or_else(|_| Cow::Borrowed(text_style))
} else {
Cow::Borrowed(text_style)
};
if line.len() + line_chunk.len() > max_line_len {
let mut chunk_len = max_line_len - line.len();
while !line_chunk.is_char_boundary(chunk_len) {
chunk_len -= 1;
}
line_chunk = &line_chunk[..chunk_len];
line_exceeded_max_len = true;
}
line.push_str(line_chunk);
styles.push((
line_chunk.len(),
RunStyle {
font_id: text_style.font_id,
color: text_style.color,
underline: text_style.underline,
},
));
}
}
}
layouts
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{elements::Empty, fonts, AnyElement, AppContext, Entity, View, ViewContext};
#[crate::test(self)]
fn test_soft_wrapping_with_carriage_returns(cx: &mut AppContext) {
cx.add_window(Default::default(), |cx| {
let mut view = TestView;
fonts::with_font_cache(cx.font_cache().clone(), || {
let mut text = Text::new("Hello\r\n", Default::default()).with_soft_wrap(true);
let (_, state) = text.layout(
SizeConstraint::new(Default::default(), vec2f(f32::INFINITY, f32::INFINITY)),
&mut view,
cx,
);
assert_eq!(state.shaped_lines.len(), 2);
assert_eq!(state.wrap_boundaries.len(), 2);
});
view
});
}
struct TestView;
impl Entity for TestView {
type Event = ();
}
impl View for TestView {
fn ui_name() -> &'static str {
"TestView"
}
fn render(&mut self, _: &mut ViewContext<Self>) -> AnyElement<Self> {
Empty::new().into_any()
}
}
}