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, 15 insertions, 8 deletions

diff --git a/helix-view/src/lib.rs b/helix-view/src/lib.rs
index 9a980446..c3f67345 100644
--- a/helix-view/src/lib.rs
+++ b/helix-view/src/lib.rs
@@ -49,13 +49,10 @@ pub enum Align {
 }
 
 pub fn align_view(doc: &Document, view: &mut View, align: Align) {
-    let pos = doc
-        .selection(view.id)
-        .primary()
-        .cursor(doc.text().slice(..));
-    let line = doc.text().char_to_line(pos);
-
-    let last_line_height = view.inner_height().saturating_sub(1);
+    let doc_text = doc.text().slice(..);
+    let cursor = doc.selection(view.id).primary().cursor(doc_text);
+    let viewport = view.inner_area(doc);
+    let last_line_height = viewport.height.saturating_sub(1);
 
     let relative = match align {
         Align::Center => last_line_height / 2,
@@ -63,10 +60,20 @@ pub fn align_view(doc: &Document, view: &mut View, align: Align) {
         Align::Bottom => last_line_height,
     };
 
-    view.offset.row = line.saturating_sub(relative);
+    let text_fmt = doc.text_format(viewport.width, None);
+    let annotations = view.text_annotations(doc, None);
+    (view.offset.anchor, view.offset.vertical_offset) = char_idx_at_visual_offset(
+        doc_text,
+        cursor,
+        -(relative as isize),
+        0,
+        &text_fmt,
+        &annotations,
+    );
 }
 
 pub use document::Document;
 pub use editor::Editor;
+use helix_core::char_idx_at_visual_offset;
 pub use theme::Theme;
 pub use view::View;