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helix/helix-core/src/text_annotations.rs

272 lines
8.2 KiB
Rust

use std::cell::Cell;
use std::convert::identity;
use std::ops::Range;
use std::rc::Rc;
use crate::syntax::Highlight;
use crate::Tendril;
/// An inline annotation is continuous text shown
/// on the screen before the grapheme that starts at
/// `char_idx`
#[derive(Debug, Clone)]
pub struct InlineAnnotation {
pub text: Tendril,
pub char_idx: usize,
}
/// Represents a **single Grapheme** that is part of the document
/// that start at `char_idx` that will be replaced with
/// a different `grapheme`.
/// If `grapheme` contains multiple graphemes the text
/// will render incorrectly.
/// If you want to overlay multiple graphemes simply
/// use multiple `Overlays`.
///
/// # Examples
///
/// The following examples are valid overlays for the following text:
///
/// `aX͎̊͢͜͝͡bc`
///
/// ```
/// use helix_core::text_annotations::Overlay;
///
/// // replaces a
/// Overlay {
/// char_idx: 0,
/// grapheme: "X".into(),
/// };
///
/// // replaces X͎̊͢͜͝͡
/// Overlay{
/// char_idx: 1,
/// grapheme: "\t".into(),
/// };
///
/// // replaces b
/// Overlay{
/// char_idx: 6,
/// grapheme: "X̢̢̟͖̲͌̋̇͑͝".into(),
/// };
/// ```
///
/// The following examples are invalid uses
///
/// ```
/// use helix_core::text_annotations::Overlay;
///
/// // overlay is not aligned at grapheme boundary
/// Overlay{
/// char_idx: 3,
/// grapheme: "x".into(),
/// };
///
/// // overlay contains multiple graphemes
/// Overlay{
/// char_idx: 0,
/// grapheme: "xy".into(),
/// };
/// ```
#[derive(Debug, Clone)]
pub struct Overlay {
pub char_idx: usize,
pub grapheme: Tendril,
}
/// Line annotations allow for virtual text between normal
/// text lines. They cause `height` empty lines to be inserted
/// below the document line that contains `anchor_char_idx`.
///
/// These lines can be filled with text in the rendering code
/// as their contents have no effect beyond visual appearance.
///
/// To insert a line after a document line simply set
/// `anchor_char_idx` to `doc.line_to_char(line_idx)`
#[derive(Debug, Clone)]
pub struct LineAnnotation {
pub anchor_char_idx: usize,
pub height: usize,
}
#[derive(Debug)]
struct Layer<A, M> {
annotations: Rc<[A]>,
current_index: Cell<usize>,
metadata: M,
}
impl<A, M: Clone> Clone for Layer<A, M> {
fn clone(&self) -> Self {
Layer {
annotations: self.annotations.clone(),
current_index: self.current_index.clone(),
metadata: self.metadata.clone(),
}
}
}
impl<A, M> Layer<A, M> {
pub fn reset_pos(&self, char_idx: usize, get_char_idx: impl Fn(&A) -> usize) {
let new_index = self
.annotations
.binary_search_by_key(&char_idx, get_char_idx)
.unwrap_or_else(identity);
self.current_index.set(new_index);
}
pub fn consume(&self, char_idx: usize, get_char_idx: impl Fn(&A) -> usize) -> Option<&A> {
let annot = self.annotations.get(self.current_index.get())?;
debug_assert!(get_char_idx(annot) >= char_idx);
if get_char_idx(annot) == char_idx {
self.current_index.set(self.current_index.get() + 1);
Some(annot)
} else {
None
}
}
}
impl<A, M> From<(Rc<[A]>, M)> for Layer<A, M> {
fn from((annotations, metadata): (Rc<[A]>, M)) -> Layer<A, M> {
Layer {
annotations,
current_index: Cell::new(0),
metadata,
}
}
}
fn reset_pos<A, M>(layers: &[Layer<A, M>], pos: usize, get_pos: impl Fn(&A) -> usize) {
for layer in layers {
layer.reset_pos(pos, &get_pos)
}
}
/// Annotations that change that is displayed when the document is render.
/// Also commonly called virtual text.
#[derive(Default, Debug, Clone)]
pub struct TextAnnotations {
inline_annotations: Vec<Layer<InlineAnnotation, Option<Highlight>>>,
overlays: Vec<Layer<Overlay, Option<Highlight>>>,
line_annotations: Vec<Layer<LineAnnotation, ()>>,
}
impl TextAnnotations {
/// Prepare the TextAnnotations for iteration starting at char_idx
pub fn reset_pos(&self, char_idx: usize) {
reset_pos(&self.inline_annotations, char_idx, |annot| annot.char_idx);
reset_pos(&self.overlays, char_idx, |annot| annot.char_idx);
reset_pos(&self.line_annotations, char_idx, |annot| {
annot.anchor_char_idx
});
}
pub fn collect_overlay_highlights(
&self,
char_range: Range<usize>,
) -> Vec<(usize, Range<usize>)> {
let mut highlights = Vec::new();
self.reset_pos(char_range.start);
for char_idx in char_range {
if let Some((_, Some(highlight))) = self.overlay_at(char_idx) {
// we don't know the number of chars the original grapheme takes
// however it doesn't matter as highlight bounderies are automatically
// aligned to grapheme boundaries in the rendering code
highlights.push((highlight.0, char_idx..char_idx + 1))
}
}
highlights
}
/// Add new inline annotations.
///
/// The annotations grapheme will be rendered with `highlight`
/// patched on top of `ui.text`.
///
/// The annotations **must be sorted** by their `char_idx`.
/// Multiple annotations with the same `char_idx` are allowed,
/// they will be display in the order that they are present in the layer.
///
/// If multiple layers contain annotations at the same position
/// the annotations that belong to the layers added first will be shown first.
pub fn add_inline_annotations(
&mut self,
layer: Rc<[InlineAnnotation]>,
highlight: Option<Highlight>,
) -> &mut Self {
self.inline_annotations.push((layer, highlight).into());
self
}
/// Add new grapheme overlays.
///
/// The overlayed grapheme will be rendered with `highlight`
/// patched on top of `ui.text`.
///
/// The overlays **must be sorted** by their `char_idx`.
/// Multiple overlays with the same `char_idx` **are allowed**.
///
/// If multiple layers contain overlay at the same position
/// the overlay from the layer added last will be show.
pub fn add_overlay(&mut self, layer: Rc<[Overlay]>, highlight: Option<Highlight>) -> &mut Self {
self.overlays.push((layer, highlight).into());
self
}
/// Add new annotation lines.
///
/// The line annotations **must be sorted** by their `char_idx`.
/// Multiple line annotations with the same `char_idx` **are not allowed**.
pub fn add_line_annotation(&mut self, layer: Rc<[LineAnnotation]>) -> &mut Self {
self.line_annotations.push((layer, ()).into());
self
}
/// Removes all line annotations, useful for vertical motions
/// so that virtual text lines are automatically skipped.
pub fn clear_line_annotations(&mut self) {
self.line_annotations.clear();
}
pub(crate) fn next_inline_annotation_at(
&self,
char_idx: usize,
) -> Option<(&InlineAnnotation, Option<Highlight>)> {
self.inline_annotations.iter().find_map(|layer| {
let annotation = layer.consume(char_idx, |annot| annot.char_idx)?;
Some((annotation, layer.metadata))
})
}
pub(crate) fn overlay_at(&self, char_idx: usize) -> Option<(&Overlay, Option<Highlight>)> {
let mut overlay = None;
for layer in &self.overlays {
while let Some(new_overlay) = layer.consume(char_idx, |annot| annot.char_idx) {
overlay = Some((new_overlay, layer.metadata));
}
}
overlay
}
pub(crate) fn annotation_lines_at(&self, char_idx: usize) -> usize {
self.line_annotations
.iter()
.map(|layer| {
let mut lines = 0;
while let Some(annot) = layer.annotations.get(layer.current_index.get()) {
if annot.anchor_char_idx == char_idx {
layer.current_index.set(layer.current_index.get() + 1);
lines += annot.height
} else {
break;
}
}
lines
})
.sum()
}
}