use std::cmp::Ordering;
use helix_core::doc_formatter::FormattedGrapheme;
use helix_core::Position;
use helix_view::editor::CursorCache;
use crate::ui::document::{LinePos, TextRenderer};
pub use diagnostics::InlineDiagnostics;
mod diagnostics;
/// Decorations are the primary mechanism for extending the text rendering.
///
/// Any on-screen element which is anchored to the rendered text in some form
/// should be implemented using this trait. Translating char positions to
/// on-screen positions can be expensive and should not be done manually in the
/// ui loop. Instead such translations are automatically performed on the fly
/// while the text is being rendered. The results are provided to this trait by
/// the rendering infrastructure.
///
/// To reserve space for virtual text lines (which is then filled by this trait) emit appropriate
/// [`LineAnnotation`](helix_core::text_annotations::LineAnnotation)s in [`helix_view::View::text_annotations`]
pub trait Decoration {
/// Called **before** a **visual** line is rendered. A visual line does not
/// necessarily correspond to a single line in a document as soft wrapping can
/// spread a single document line across multiple visual lines.
///
/// This function is called before text is rendered as any decorations should
/// never overlap the document text. That means that setting the forground color
/// here is (essentially) useless as the text color is overwritten by the
/// rendered text. This _of course_ doesn't apply when rendering inside virtual lines
/// below the line reserved by `LineAnnotation`s as no text will be rendered here.
fn decorate_line(&mut self, _renderer: &mut TextRenderer, _pos: LinePos) {}
/// Called **after** a **visual** line is rendered. A visual line does not
/// necessarily correspond to a single line in a document as soft wrapping can
/// spread a single document line across multiple visual lines.
///
/// This function is called after text is rendered so that decorations can collect
/// horizontal positions on the line (see [`Decoration::decorate_grapheme`]) first and
/// use those positions` while rendering
/// virtual text.
/// That means that setting the forground color
/// here is (essentially) useless as the text color is overwritten by the
/// rendered text. This -ofcourse- doesn't apply when rendering inside virtual lines
/// below the line reserved by `LineAnnotation`s. e as no text will be rendered here.
/// **Note**: To avoid overlapping decorations in the virtual lines, each decoration
/// must return the number of virtual text lines it has taken up. Each `Decoration` recieves
/// an offset `virt_off` based on these return values where it can render virtual text:
///
/// That means that a `render_line` implementation that returns `X` can render virtual text
/// in the following area:
/// ``` no-compile
/// let start = inner.y + pos.virtual_line + virt_off;
/// start .. start + X
/// ````
fn render_virt_lines(
&mut self,
_renderer: &mut TextRenderer,
_pos: LinePos,
_virt_off: Position,
) -> Position {
Position::new(0, 0)
}
fn reset_pos(&mut self, _pos: usize) -> usize {
usize::MAX
}
fn skip_concealed_anchor(&mut self, conceal_end_char_idx: usize) -> usize {
self.reset_pos(conceal_end_char_idx)
}
/// This function is called **before** the grapheme at `char_idx` is rendered.
///
/// # Returns
///
/// The char idx of the next grapheme that this function should be called for
fn decorate_grapheme(
&mut self,
_renderer: &mut TextRenderer,
_grapheme: &FormattedGrapheme,
) -> usize {
usize::MAX
}
}
impl<F: FnMut(&mut TextRenderer, LinePos)> Decoration for F {
fn decorate_line(&mut self, renderer: &mut TextRenderer, pos: LinePos) {
self(renderer, pos);
}
}
#[derive(Default)]
pub struct DecorationManager<'a> {
decorations: Vec<(Box<dyn Decoration + 'a>, usize)>,
}
impl<'a> DecorationManager<'a> {
pub fn add_decoration(&mut self, decoration: impl Decoration + 'a) {
self.decorations.push((Box::new(decoration), 0));
}
pub fn prepare_for_rendering(&mut self, first_visible_char: usize) {
for (decoration, next_position) in &mut self.decorations {
*next_position = decoration.reset_pos(first_visible_char)
}
}
pub fn decorate_grapheme(&mut self, renderer: &mut TextRenderer, grapheme: &FormattedGrapheme) {
for (decoration, hook_char_idx) in &mut self.decorations {
loop {
match (*hook_char_idx).cmp(&grapheme.char_idx) {
// this grapheme has been concealed or we are at the first grapheme
Ordering::Less => {
*hook_char_idx = decoration.skip_concealed_anchor(grapheme.char_idx)
}
Ordering::Equal => {
*hook_char_idx = decoration.decorate_grapheme(renderer, grapheme)
}
Ordering::Greater => break,
}
}
}
}
pub fn decorate_line(&mut self, renderer: &mut TextRenderer, pos: LinePos) {
for (decoration, _) in &mut self.decorations {
decoration.decorate_line(renderer, pos);
}
}
pub fn render_virtual_lines(
&mut self,
renderer: &mut TextRenderer,
pos: LinePos,
line_width: usize,
) {
let mut virt_off = Position::new(1, line_width); // start at 1 so the line is never overwritten
for (decoration, _) in &mut self.decorations {
virt_off += decoration.render_virt_lines(renderer, pos, virt_off);
}
}
}
/// Cursor rendering is done externally so all the cursor decoration
/// does is save the position of primary cursor
pub struct Cursor<'a> {
pub cache: &'a CursorCache,
pub primary_cursor: usize,
}
impl Decoration for Cursor<'_> {
fn reset_pos(&mut self, pos: usize) -> usize {
if pos <= self.primary_cursor {
self.primary_cursor
} else {
usize::MAX
}
}
fn decorate_grapheme(
&mut self,
renderer: &mut TextRenderer,
grapheme: &FormattedGrapheme,
) -> usize {
if renderer.column_in_bounds(grapheme.visual_pos.col)
&& renderer.offset.row < grapheme.visual_pos.row
{
let position = grapheme.visual_pos - renderer.offset;
self.cache.set(Some(position));
}
usize::MAX
}
}