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Rust
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187//! Source lines laid out on a fixed grid: tabs expanded to stops, wide//! characters given two cells, and long lines wrapped at the column limit.
use crate::highlight::Colors;use arborium_theme::theme::Color;use unicode_width::UnicodeWidthChar;
/// One glyph at a grid column; a wide glyph also covers the next column.#[derive(Debug, Clone, Copy, PartialEq)]pub struct Glyph { pub column: usize, pub ch: char, pub color: Color,}
/// One row of the image: a source line, or the continuation of a wrapped one.#[derive(Debug, Clone, PartialEq)]pub struct Row { pub line: usize, pub continued: bool, pub glyphs: Vec<Glyph>,}
/// The 1-based lines of `source` with the byte offset each starts at./// A final newline ends the last line rather than starting an empty one.pub fn lines(source: &str) -> Vec<(usize, &str)> { let mut offset = 0; let mut lines = Vec::new(); for line in source.split_inclusive('\n') { let text = line.strip_suffix('\n').unwrap_or(line); lines.push((offset, text.strip_suffix('\r').unwrap_or(text))); offset += line.len(); } lines}
pub fn rows( lines: &[(usize, &str)], first: usize, colors: &Colors, columns: usize, tab_width: usize,) -> Vec<Row> { let mut rows = Vec::new(); let mut cursor = colors.cursor(lines.first().map_or(0, |(offset, _)| *offset)); for (index, (offset, text)) in lines.iter().enumerate() { let line = first + index; let mut row = Row { line, continued: false, glyphs: Vec::new(), }; let mut column = 0; for (at, ch) in text.char_indices() { let color = cursor.at(offset + at); let (ch, width) = match ch { '\t' => (' ', tab_width - column % tab_width), ch if ch.is_control() => ('\u{FFFD}', 1), // Combining marks have no cell of their own; they are dropped. ch => match ch.width() { Some(0) => continue, width => (ch, width.unwrap_or(1)), }, }; if column + width > columns && column > 0 { rows.push(std::mem::replace( &mut row, Row { line, continued: true, glyphs: Vec::new(), }, )); column = 0; } if ch != ' ' { row.glyphs.push(Glyph { column, ch, color }); } column += width.min(columns); } rows.push(row); } rows}
/// Consecutive rows that fit one image, as evenly sized as the fewest pages/// allow, so a range just over one page is not a full page and a sliver./// A page ends at a line boundary unless one line is taller than a page.pub fn pages(rows: &[Row], max_rows: usize) -> Vec<std::ops::Range<usize>> { let count = rows.len().div_ceil(max_rows).max(1); let size = rows.len().div_ceil(count).max(1); let mut pages = Vec::new(); let mut start = 0; while start < rows.len() { let mut end = (start + size).min(rows.len()); if end < rows.len() && rows[end].continued { let boundary = (start + 1..end).rev().find(|&index| !rows[index].continued); end = boundary.unwrap_or(end); } pages.push(start..end); start = end; } pages}
#[cfg(test)]mod tests { use super::*; use arborium_theme::theme::builtin;
fn plain(source: &str, columns: usize) -> Vec<Row> { let colors = Colors::new(source, None, &builtin::github_light()); rows(&lines(source), 1, &colors, columns, 4) }
fn text(row: &Row) -> String { let mut text = String::new(); for glyph in &row.glyphs { while text.chars().count() < glyph.column { text.push(' '); } text.push(glyph.ch); } text }
#[test] fn lines_keep_offsets_and_drop_line_endings() { assert_eq!( lines("a\r\nbc\n\nd"), vec![(0, "a"), (3, "bc"), (6, ""), (7, "d")] ); assert_eq!(lines("a\n"), vec![(0, "a")]); assert!(lines("").is_empty()); }
#[test] fn tabs_stop_at_multiples_of_the_tab_width() { let rows = plain("a\tb\n\tc", 79); assert_eq!(text(&rows[0]), "a b"); assert_eq!(text(&rows[1]), " c"); }
#[test] fn long_lines_wrap_and_wide_characters_never_split() { let rows = plain("abcdefg\n漢字漢", 3); let wrapped: Vec<_> = rows .iter() .map(|row| (row.line, row.continued, text(row))) .collect(); assert_eq!( wrapped, vec![ (1, false, "abc".into()), (1, true, "def".into()), (1, true, "g".into()), (2, false, "漢".into()), (2, true, "字".into()), (2, true, "漢".into()), ] ); assert_eq!(rows[3].glyphs[0].column, 0); }
#[test] fn control_characters_are_visible_and_empty_lines_keep_a_row() { let rows = plain("a\u{1b}b\n\nc\u{301}", 79); assert_eq!(text(&rows[0]), "a\u{FFFD}b"); assert_eq!(rows[1].glyphs, vec![]); assert_eq!(text(&rows[2]), "c"); }
#[test] fn pages_break_between_lines_unless_one_line_fills_a_page() { let rows = plain("aa\nbbbbbb\ncc\ndddddddddd", 2); // rows: a(1) b b b(2) c(3) d d d d d(4) assert_eq!(pages(&rows, 3), vec![0..1, 1..4, 4..5, 5..8, 8..10]); }
#[test] fn a_range_just_over_one_page_splits_evenly() { let rows = plain(&"x\n".repeat(81), 79); assert_eq!(pages(&rows, 80), vec![0..41, 41..81]); assert_eq!(pages(&rows[..80], 80), vec![0..80]); }}