feat: add unicode-aware soft-wrap modes and wrapped rendering (#8)

* feat(textarea): add unicode-aware soft-wrap modes and wrapped rendering

- add WrapMode API/state: None, Word, Glyph, WordOrGlyph
- keep None behavior unchanged (horizontal scroll)
- implement wrapped render path with logical-to-visual row mapping
- add Unicode-aware wrapping via unicode-segmentation + unicode-width
- make wrap width tab-aware to prevent hidden text
- apply cursor-line style on wrapped continuation rows
- fix selection at soft-wrap boundaries (no synthetic highlighted space)
- add wrap-focused tests for long text, newlines, tabs, tiny widths, and line-number
    continuations

* chore(release): bump to v0.9.0 and update README/CHANGELOG

tests/wrap.rs

@@ -0,0 +1,266 @@
+use ratatui::buffer::Buffer;
+use ratatui::layout::Rect;
+use ratatui::style::{Color, Style};
+use ratatui::widgets::Widget as _;
+use tui_textarea::{CursorMove, TextArea, WrapMode};
+
+fn render_lines(textarea: &TextArea<'_>, width: u16, height: u16) -> Vec<String> {
+    let area = Rect {
+        x: 0,
+        y: 0,
+        width,
+        height,
+    };
+    let mut buf = Buffer::empty(area);
+    textarea.render(area, &mut buf);
+
+    (0..height)
+        .map(|y| {
+            let mut line = String::new();
+            for x in 0..width {
+                line.push_str(buf[(x, y)].symbol());
+            }
+            line
+        })
+        .collect()
+}
+
+fn render_buffer(textarea: &TextArea<'_>, width: u16, height: u16) -> Buffer {
+    let area = Rect {
+        x: 0,
+        y: 0,
+        width,
+        height,
+    };
+    let mut buf = Buffer::empty(area);
+    textarea.render(area, &mut buf);
+    buf
+}
+
+#[test]
+fn wrap_mode_default_is_none() {
+    let textarea = TextArea::default();
+    assert_eq!(textarea.wrap_mode(), WrapMode::None);
+}
+
+#[test]
+fn none_mode_keeps_horizontal_behavior() {
+    let textarea = TextArea::from(["abcdef"]);
+    let lines = render_lines(&textarea, 5, 2);
+    assert_eq!(lines, vec!["abcde".to_string(), "     ".to_string()]);
+}
+
+#[test]
+fn word_or_glyph_mode_soft_wraps() {
+    let mut textarea = TextArea::from(["abcdef"]);
+    textarea.set_wrap_mode(WrapMode::WordOrGlyph);
+    let lines = render_lines(&textarea, 5, 2);
+    assert_eq!(lines, vec!["abcde".to_string(), "f    ".to_string()]);
+}
+
+#[test]
+fn word_mode_does_not_split_long_word() {
+    let mut textarea = TextArea::from(["abcdefgh"]);
+    textarea.set_wrap_mode(WrapMode::Word);
+    let lines = render_lines(&textarea, 5, 2);
+    assert_eq!(lines, vec!["abcde".to_string(), "     ".to_string()]);
+}
+
+#[test]
+fn word_mode_wraps_with_newlines() {
+    let mut textarea = TextArea::from(["hello world", "again here"]);
+    textarea.set_wrap_mode(WrapMode::Word);
+
+    let lines = render_lines(&textarea, 6, 4);
+    assert_eq!(
+        lines,
+        vec![
+            "hello ".to_string(),
+            "world ".to_string(),
+            "again ".to_string(),
+            "here  ".to_string(),
+        ]
+    );
+}
+
+#[test]
+fn none_mode_long_multiline_text_stays_unwrapped() {
+    let textarea = TextArea::from(["first very long line", "second very long line"]);
+    let lines = render_lines(&textarea, 8, 4);
+    assert_eq!(
+        lines,
+        vec![
+            "first ve".to_string(),
+            "second v".to_string(),
+            "        ".to_string(),
+            "        ".to_string(),
+        ]
+    );
+}
+
+#[test]
+fn word_mode_long_paragraph_wraps_by_words() {
+    let mut textarea = TextArea::from(["lorem ipsum dolor sit amet consectetur adipiscing elit"]);
+    textarea.set_wrap_mode(WrapMode::Word);
+    let lines = render_lines(&textarea, 12, 6);
+    assert_eq!(
+        lines,
+        vec![
+            "lorem ipsum ".to_string(),
+            "dolor sit   ".to_string(),
+            "amet        ".to_string(),
+            "consectetur ".to_string(),
+            "adipiscing  ".to_string(),
+            "elit        ".to_string(),
+        ]
+    );
+}
+
+#[test]
+fn glyph_mode_splits_long_token() {
+    let mut textarea = TextArea::from(["0123456789abcdefghijklmnopqrstuvwxyz"]);
+    textarea.set_wrap_mode(WrapMode::Glyph);
+    let lines = render_lines(&textarea, 10, 4);
+    assert_eq!(
+        lines,
+        vec![
+            "0123456789".to_string(),
+            "abcdefghij".to_string(),
+            "klmnopqrst".to_string(),
+            "uvwxyz    ".to_string(),
+        ]
+    );
+}
+
+#[test]
+fn word_and_word_or_glyph_differ_for_long_words() {
+    let text = "alpha supercalifragilisticexpialidocious omega";
+
+    let mut word = TextArea::from([text]);
+    word.set_wrap_mode(WrapMode::Word);
+    let word_lines = render_lines(&word, 10, 4);
+    assert_eq!(
+        word_lines,
+        vec![
+            "alpha     ".to_string(),
+            "supercalif".to_string(),
+            " omega    ".to_string(),
+            "          ".to_string(),
+        ]
+    );
+
+    let mut word_or_glyph = TextArea::from([text]);
+    word_or_glyph.set_wrap_mode(WrapMode::WordOrGlyph);
+    let word_or_glyph_lines = render_lines(&word_or_glyph, 10, 6);
+    assert_eq!(
+        word_or_glyph_lines,
+        vec![
+            "alpha     ".to_string(),
+            "supercalif".to_string(),
+            "ragilistic".to_string(),
+            "expialidoc".to_string(),
+            "ious      ".to_string(),
+            " omega    ".to_string(),
+        ]
+    );
+}
+
+#[test]
+fn wrapped_mode_line_numbers_on_continuation_rows() {
+    let mut textarea = TextArea::from(["abcdefghijk", "xy"]);
+    textarea.set_wrap_mode(WrapMode::WordOrGlyph);
+    textarea.set_line_number_style(Style::default());
+
+    let lines = render_lines(&textarea, 8, 4);
+    assert_eq!(
+        lines,
+        vec![
+            " 1 abcde".to_string(),
+            "   fghij".to_string(),
+            "   k    ".to_string(),
+            " 2 xy   ".to_string(),
+        ]
+    );
+}
+
+#[test]
+fn wrapped_mode_handles_tiny_width() {
+    let mut textarea = TextArea::from(["abcd"]);
+    textarea.set_wrap_mode(WrapMode::WordOrGlyph);
+
+    let lines = render_lines(&textarea, 1, 4);
+    assert_eq!(
+        lines,
+        vec![
+            "a".to_string(),
+            "b".to_string(),
+            "c".to_string(),
+            "d".to_string(),
+        ]
+    );
+}
+
+#[test]
+fn wrapped_mode_preserves_empty_logical_lines() {
+    let mut textarea = TextArea::from(["ab", "", "cd"]);
+    textarea.set_wrap_mode(WrapMode::WordOrGlyph);
+
+    let lines = render_lines(&textarea, 2, 3);
+    assert_eq!(
+        lines,
+        vec!["ab".to_string(), "  ".to_string(), "cd".to_string(),]
+    );
+}
+
+#[test]
+fn glyph_mode_combining_grapheme_renders_in_two_rows() {
+    let mut textarea = TextArea::from(["e\u{301}x"]);
+    textarea.set_wrap_mode(WrapMode::Glyph);
+
+    let lines = render_lines(&textarea, 1, 2);
+    assert_eq!(lines, vec!["e".to_string(), "x".to_string()]);
+}
+
+#[test]
+fn wrapped_mode_scrolls_to_cursor_visual_row() {
+    let mut textarea = TextArea::from(["abcdefghijklmnopqrstuvwxyz"]);
+    textarea.set_wrap_mode(WrapMode::WordOrGlyph);
+    textarea.move_cursor(CursorMove::End);
+
+    let lines = render_lines(&textarea, 5, 2);
+    assert_eq!(lines, vec!["uvwxy".to_string(), "z    ".to_string()]);
+}
+
+#[test]
+fn wrapped_mode_with_tab_does_not_hide_following_text() {
+    let mut textarea = TextArea::from(["\tX"]);
+    textarea.set_wrap_mode(WrapMode::WordOrGlyph);
+    let lines = render_lines(&textarea, 2, 2);
+    assert_eq!(lines, vec!["  ".to_string(), "X ".to_string()]);
+}
+
+#[test]
+fn cursor_line_style_applies_to_wrapped_continuation_rows() {
+    let mut textarea = TextArea::from(["abcdefghij"]);
+    textarea.set_wrap_mode(WrapMode::WordOrGlyph);
+    let style = Style::default().bg(Color::Red);
+    textarea.set_cursor_line_style(style);
+
+    let buf = render_buffer(&textarea, 5, 2);
+    assert_eq!(buf[(1, 1)].style().bg, style.bg);
+}
+
+#[test]
+fn selection_does_not_extend_with_synthetic_space_on_wrap_boundary() {
+    let mut textarea = TextArea::from(["hello world again"]);
+    textarea.set_wrap_mode(WrapMode::Word);
+    textarea.set_cursor_line_style(Style::default());
+    let select_style = Style::default().bg(Color::Blue);
+    textarea.set_selection_style(select_style);
+    textarea.start_selection();
+    textarea.move_cursor(CursorMove::End);
+
+    let buf = render_buffer(&textarea, 10, 3);
+    assert_eq!(buf[(5, 0)].style().bg, select_style.bg);
+    assert_ne!(buf[(6, 0)].style().bg, select_style.bg);
+}