rework positioning/rendering and enable softwrap/virtual text (#5420)

* rework positioning/rendering, enables softwrap/virtual text

This commit is a large rework of the core text positioning and
rendering code in helix to remove the assumption that on-screen
columns/lines correspond to text columns/lines.

A generic `DocFormatter` is introduced that positions graphemes on
and is used both for rendering and for movements/scrolling.
Both virtual text support (inline, grapheme overlay and multi-line)
and a capable softwrap implementation is included.

fix picker highlight

cleanup doc formatter, use word bondaries for wrapping

make visual vertical movement a seperate commnad

estimate line gutter width to improve performance

cache cursor position

cleanup and optimize doc formatter

cleanup documentation

fix typos

Co-authored-by: Daniel Hines <d4hines@gmail.com>

update documentation

fix panic in last_visual_line funciton

improve soft-wrap documentation

add extend_visual_line_up/down commands

fix non-visual vertical movement

streamline virtual text highlighting, add softwrap indicator

fix cursor position if softwrap is disabled

improve documentation of text_annotations module

avoid crashes if view anchor is out of bounds

fix: consider horizontal offset when traslation char_idx -> vpos

improve default configuration

fix: mixed up horizontal and vertical offset

reset view position after config reload

apply suggestions from review

disabled softwrap for very small screens to avoid endless spin

fix wrap_indicator setting

fix bar cursor disappearring on the EOF character

add keybinding for linewise vertical movement

fix: inconsistent gutter highlights

improve virtual text API

make scope idx lookup more ergonomic

allow overlapping overlays

correctly track char_pos for virtual text

adjust configuration

deprecate old position fucntions

fix infinite loop in highlight lookup

fix gutter style

fix formatting

document max-line-width interaction with softwrap

change wrap-indicator example to use empty string

fix: rare panic when view is in invalid state (bis)

* Apply suggestions from code review

Co-authored-by: Michael Davis <mcarsondavis@gmail.com>

* improve documentation for positoning functions

* simplify tests

* fix documentation of Grapheme::width

* Apply suggestions from code review

Co-authored-by: Michael Davis <mcarsondavis@gmail.com>

* add explicit drop invocation

* Add explicit MoveFn type alias

* add docuntation to Editor::cursor_cache

* fix a few typos

* explain use of allow(deprecated)

* make gj and gk extend in select mode

* remove unneded debug and TODO

* mark tab_width_at #[inline]

* add fast-path to move_vertically_visual in case softwrap is disabled

* rename first_line to first_visual_line

* simplify duplicate if/else

---------

Co-authored-by: Michael Davis <mcarsondavis@gmail.com>

1 files changed, 61 insertions, 13 deletions

diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index 6b33ea6a..798b5400 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -1,7 +1,11 @@
 use anyhow::{anyhow, bail, Context, Error};
+use arc_swap::access::DynAccess;
 use futures_util::future::BoxFuture;
 use futures_util::FutureExt;
 use helix_core::auto_pairs::AutoPairs;
+use helix_core::doc_formatter::TextFormat;
+use helix_core::syntax::Highlight;
+use helix_core::text_annotations::TextAnnotations;
 use helix_core::Range;
 use helix_vcs::{DiffHandle, DiffProviderRegistry};
 
@@ -26,8 +30,8 @@ use helix_core::{
     DEFAULT_LINE_ENDING,
 };
 
-use crate::editor::RedrawHandle;
-use crate::{DocumentId, Editor, View, ViewId};
+use crate::editor::{Config, RedrawHandle};
+use crate::{DocumentId, Editor, Theme, View, ViewId};
 
 /// 8kB of buffer space for encoding and decoding `Rope`s.
 const BUF_SIZE: usize = 8192;
@@ -127,6 +131,7 @@ pub struct Document {
     // it back as it separated from the edits. We could split out the parts manually but that will
     // be more troublesome.
     pub history: Cell<History>,
+    pub config: Arc<dyn DynAccess<Config>>,
 
     pub savepoint: Option<Transaction>,
 
@@ -351,7 +356,11 @@ use helix_lsp::lsp;
 use url::Url;
 
 impl Document {
-    pub fn from(text: Rope, encoding: Option<&'static encoding::Encoding>) -> Self {
+    pub fn from(
+        text: Rope,
+        encoding: Option<&'static encoding::Encoding>,
+        config: Arc<dyn DynAccess<Config>>,
+    ) -> Self {
         let encoding = encoding.unwrap_or(encoding::UTF_8);
         let changes = ChangeSet::new(&text);
         let old_state = None;
@@ -377,9 +386,13 @@ impl Document {
             modified_since_accessed: false,
             language_server: None,
             diff_handle: None,
+            config,
         }
     }
-
+    pub fn default(config: Arc<dyn DynAccess<Config>>) -> Self {
+        let text = Rope::from(DEFAULT_LINE_ENDING.as_str());
+        Self::from(text, None, config)
+    }
     // TODO: async fn?
     /// Create a new document from `path`. Encoding is auto-detected, but it can be manually
     /// overwritten with the `encoding` parameter.
@@ -387,6 +400,7 @@ impl Document {
         path: &Path,
         encoding: Option<&'static encoding::Encoding>,
         config_loader: Option<Arc<syntax::Loader>>,
+        config: Arc<dyn DynAccess<Config>>,
     ) -> Result<Self, Error> {
         // Open the file if it exists, otherwise assume it is a new file (and thus empty).
         let (rope, encoding) = if path.exists() {
@@ -398,7 +412,7 @@ impl Document {
             (Rope::from(DEFAULT_LINE_ENDING.as_str()), encoding)
         };
 
-        let mut doc = Self::from(rope, Some(encoding));
+        let mut doc = Self::from(rope, Some(encoding), config);
 
         // set the path and try detecting the language
         doc.set_path(Some(path))?;
@@ -1192,12 +1206,34 @@ impl Document {
             None => global_config,
         }
     }
-}
 
-impl Default for Document {
-    fn default() -> Self {
-        let text = Rope::from(DEFAULT_LINE_ENDING.as_str());
-        Self::from(text, None)
+    pub fn text_format(&self, mut viewport_width: u16, theme: Option<&Theme>) -> TextFormat {
+        if let Some(max_line_len) = self
+            .language_config()
+            .and_then(|config| config.max_line_length)
+        {
+            viewport_width = viewport_width.min(max_line_len as u16)
+        }
+        let config = self.config.load();
+        let soft_wrap = &config.soft_wrap;
+        let tab_width = self.tab_width() as u16;
+        TextFormat {
+            soft_wrap: soft_wrap.enable && viewport_width > 10,
+            tab_width,
+            max_wrap: soft_wrap.max_wrap.min(viewport_width / 4),
+            max_indent_retain: soft_wrap.max_indent_retain.min(viewport_width * 2 / 5),
+            // avoid spinning forever when the window manager
+            // sets the size to something tiny
+            viewport_width,
+            wrap_indicator: soft_wrap.wrap_indicator.clone().into_boxed_str(),
+            wrap_indicator_highlight: theme
+                .and_then(|theme| theme.find_scope_index("ui.virtual.wrap"))
+                .map(Highlight),
+        }
+    }
+
+    pub fn text_annotations(&self, _theme: Option<&Theme>) -> TextAnnotations {
+        TextAnnotations::default()
     }
 }
 
@@ -1236,13 +1272,19 @@ impl Display for FormatterError {
 
 #[cfg(test)]
 mod test {
+    use arc_swap::ArcSwap;
+
     use super::*;
 
     #[test]
     fn changeset_to_changes_ignore_line_endings() {
         use helix_lsp::{lsp, Client, OffsetEncoding};
         let text = Rope::from("hello\r\nworld");
-        let mut doc = Document::from(text, None);
+        let mut doc = Document::from(
+            text,
+            None,
+            Arc::new(ArcSwap::new(Arc::new(Config::default()))),
+        );
         let view = ViewId::default();
         doc.set_selection(view, Selection::single(0, 0));
 
@@ -1276,7 +1318,11 @@ mod test {
     fn changeset_to_changes() {
         use helix_lsp::{lsp, Client, OffsetEncoding};
         let text = Rope::from("hello");
-        let mut doc = Document::from(text, None);
+        let mut doc = Document::from(
+            text,
+            None,
+            Arc::new(ArcSwap::new(Arc::new(Config::default()))),
+        );
         let view = ViewId::default();
         doc.set_selection(view, Selection::single(5, 5));
 
@@ -1389,7 +1435,9 @@ mod test {
     #[test]
     fn test_line_ending() {
         assert_eq!(
-            Document::default().text().to_string(),
+            Document::default(Arc::new(ArcSwap::new(Arc::new(Config::default()))))
+                .text()
+                .to_string(),
             DEFAULT_LINE_ENDING.as_str()
         );
     }