use crate::{FontId, FontRun, Pixels, PlatformTextSystem, SharedString, TextRun, px}; use collections::HashMap; use std::{iter, sync::Arc}; /// The GPUI line wrapper, used to wrap lines of text to a given width. pub struct LineWrapper { platform_text_system: Arc, pub(crate) font_id: FontId, pub(crate) font_size: Pixels, cached_ascii_char_widths: [Option; 128], cached_other_char_widths: HashMap, } impl LineWrapper { /// The maximum indent that can be applied to a line. pub const MAX_INDENT: u32 = 256; pub(crate) fn new( font_id: FontId, font_size: Pixels, text_system: Arc, ) -> Self { Self { platform_text_system: text_system, font_id, font_size, cached_ascii_char_widths: [None; 128], cached_other_char_widths: HashMap::default(), } } /// Wrap a line of text to the given width with this wrapper's font and font size. pub fn wrap_line<'a>( &'a mut self, fragments: &'a [LineFragment], wrap_width: Pixels, ) -> impl Iterator + 'a { let mut width = px(0.); let mut first_non_whitespace_ix = None; let mut indent = None; let mut last_candidate_ix = 0; let mut last_candidate_width = px(0.); let mut last_wrap_ix = 0; let mut prev_c = '\0'; let mut index = 0; let mut candidates = fragments .iter() .flat_map(move |fragment| fragment.wrap_boundary_candidates()) .peekable(); iter::from_fn(move || { for candidate in candidates.by_ref() { let ix = index; index += candidate.len_utf8(); let mut new_prev_c = prev_c; let item_width = match candidate { WrapBoundaryCandidate::Char { character: c } => { if c == '\n' { continue; } if Self::is_word_char(c) { if prev_c == ' ' && c != ' ' && first_non_whitespace_ix.is_some() { last_candidate_ix = ix; last_candidate_width = width; } } else { // CJK may not be space separated, e.g.: `Hello world你好世界` if c != ' ' && first_non_whitespace_ix.is_some() { last_candidate_ix = ix; last_candidate_width = width; } } if c != ' ' && first_non_whitespace_ix.is_none() { first_non_whitespace_ix = Some(ix); } new_prev_c = c; self.width_for_char(c) } WrapBoundaryCandidate::Element { width: element_width, .. } => { if prev_c == ' ' && first_non_whitespace_ix.is_some() { last_candidate_ix = ix; last_candidate_width = width; } if first_non_whitespace_ix.is_none() { first_non_whitespace_ix = Some(ix); } element_width } }; width += item_width; if width > wrap_width && ix > last_wrap_ix { if let (None, Some(first_non_whitespace_ix)) = (indent, first_non_whitespace_ix) { indent = Some( Self::MAX_INDENT.min((first_non_whitespace_ix - last_wrap_ix) as u32), ); } if last_candidate_ix > 0 { last_wrap_ix = last_candidate_ix; width -= last_candidate_width; last_candidate_ix = 0; } else { last_wrap_ix = ix; width = item_width; } if let Some(indent) = indent { width += self.width_for_char(' ') * indent as f32; } return Some(Boundary::new(last_wrap_ix, indent.unwrap_or(0))); } prev_c = new_prev_c; } None }) } /// Truncate a line of text to the given width with this wrapper's font and font size. pub fn truncate_line( &mut self, line: SharedString, truncate_width: Pixels, truncation_suffix: &str, runs: &mut Vec, ) -> SharedString { let mut width = px(0.); let mut suffix_width = truncation_suffix .chars() .map(|c| self.width_for_char(c)) .fold(px(0.0), |a, x| a + x); let mut char_indices = line.char_indices(); let mut truncate_ix = 0; for (ix, c) in char_indices { if width + suffix_width < truncate_width { truncate_ix = ix; } let char_width = self.width_for_char(c); width += char_width; if width.floor() > truncate_width { let result = SharedString::from(format!("{}{}", &line[..truncate_ix], truncation_suffix)); update_runs_after_truncation(&result, truncation_suffix, runs); return result; } } line } pub(crate) fn is_word_char(c: char) -> bool { // ASCII alphanumeric characters, for English, numbers: `Hello123`, etc. c.is_ascii_alphanumeric() || // Latin script in Unicode for French, German, Spanish, etc. // Latin-1 Supplement // https://en.wikipedia.org/wiki/Latin-1_Supplement matches!(c, '\u{00C0}'..='\u{00FF}') || // Latin Extended-A // https://en.wikipedia.org/wiki/Latin_Extended-A matches!(c, '\u{0100}'..='\u{017F}') || // Latin Extended-B // https://en.wikipedia.org/wiki/Latin_Extended-B matches!(c, '\u{0180}'..='\u{024F}') || // Cyrillic for Russian, Ukrainian, etc. // https://en.wikipedia.org/wiki/Cyrillic_script_in_Unicode matches!(c, '\u{0400}'..='\u{04FF}') || // Some other known special characters that should be treated as word characters, // e.g. `a-b`, `var_name`, `I'm`, '@mention`, `#hashtag`, `100%`, `3.1415`, `2^3`, `a~b`, etc. matches!(c, '-' | '_' | '.' | '\'' | '$' | '%' | '@' | '#' | '^' | '~' | ',' | '!' | ';' | '*') || // Characters that used in URL, e.g. `https://github.com/zed-industries/zed?a=1&b=2` for better wrapping a long URL. matches!(c, '/' | ':' | '?' | '&' | '=') || // `⋯` character is special used in Zed, to keep this at the end of the line. matches!(c, '⋯') } #[inline(always)] fn width_for_char(&mut self, c: char) -> Pixels { if (c as u32) < 128 { if let Some(cached_width) = self.cached_ascii_char_widths[c as usize] { cached_width } else { let width = self.compute_width_for_char(c); self.cached_ascii_char_widths[c as usize] = Some(width); width } } else if let Some(cached_width) = self.cached_other_char_widths.get(&c) { *cached_width } else { let width = self.compute_width_for_char(c); self.cached_other_char_widths.insert(c, width); width } } fn compute_width_for_char(&self, c: char) -> Pixels { let mut buffer = [0; 4]; let buffer = c.encode_utf8(&mut buffer); self.platform_text_system .layout_line( buffer, self.font_size, &[FontRun { len: buffer.len(), font_id: self.font_id, }], ) .width } } fn update_runs_after_truncation(result: &str, ellipsis: &str, runs: &mut Vec) { let mut truncate_at = result.len() - ellipsis.len(); let mut run_end = None; for (run_index, run) in runs.iter_mut().enumerate() { if run.len <= truncate_at { truncate_at -= run.len; } else { run.len = truncate_at + ellipsis.len(); run_end = Some(run_index + 1); break; } } if let Some(run_end) = run_end { runs.truncate(run_end); } } /// A fragment of a line that can be wrapped. pub enum LineFragment<'a> { /// A text fragment consisting of characters. Text { /// The text content of the fragment. text: &'a str, }, /// A non-text element with a fixed width. Element { /// The width of the element in pixels. width: Pixels, /// The UTF-8 encoded length of the element. len_utf8: usize, }, } impl<'a> LineFragment<'a> { /// Creates a new text fragment from the given text. pub fn text(text: &'a str) -> Self { LineFragment::Text { text } } /// Creates a new non-text element with the given width and UTF-8 encoded length. pub fn element(width: Pixels, len_utf8: usize) -> Self { LineFragment::Element { width, len_utf8 } } fn wrap_boundary_candidates(&self) -> impl Iterator { let text = match self { LineFragment::Text { text } => text, LineFragment::Element { .. } => "\0", }; text.chars().map(move |character| { if let LineFragment::Element { width, len_utf8 } = self { WrapBoundaryCandidate::Element { width: *width, len_utf8: *len_utf8, } } else { WrapBoundaryCandidate::Char { character } } }) } } enum WrapBoundaryCandidate { Char { character: char }, Element { width: Pixels, len_utf8: usize }, } impl WrapBoundaryCandidate { pub fn len_utf8(&self) -> usize { match self { WrapBoundaryCandidate::Char { character } => character.len_utf8(), WrapBoundaryCandidate::Element { len_utf8: len, .. } => *len, } } } /// A boundary between two lines of text. #[derive(Copy, Clone, Debug, PartialEq, Eq)] pub struct Boundary { /// The index of the last character in a line pub ix: usize, /// The indent of the next line. pub next_indent: u32, } impl Boundary { fn new(ix: usize, next_indent: u32) -> Self { Self { ix, next_indent } } } #[cfg(test)] mod tests { use super::*; use crate::{ Font, FontFeatures, FontStyle, FontWeight, Hsla, TestAppContext, TestDispatcher, font, }; #[cfg(target_os = "macos")] use crate::{TextRun, WindowTextSystem, WrapBoundary}; use rand::prelude::*; fn build_wrapper() -> LineWrapper { let dispatcher = TestDispatcher::new(StdRng::seed_from_u64(0)); let cx = TestAppContext::build(dispatcher, None); let id = cx.text_system().resolve_font(&font(".ZedMono")); LineWrapper::new(id, px(16.), cx.text_system().platform_text_system.clone()) } fn generate_test_runs(input_run_len: &[usize]) -> Vec { input_run_len .iter() .map(|run_len| TextRun { len: *run_len, font: Font { family: "Dummy".into(), features: FontFeatures::default(), fallbacks: None, weight: FontWeight::default(), style: FontStyle::Normal, }, color: Hsla::default(), background_color: None, underline: None, strikethrough: None, }) .collect() } #[test] fn test_wrap_line() { let mut wrapper = build_wrapper(); assert_eq!( wrapper .wrap_line(&[LineFragment::text("aa bbb cccc ddddd eeee")], px(72.)) .collect::>(), &[ Boundary::new(7, 0), Boundary::new(12, 0), Boundary::new(18, 0) ], ); assert_eq!( wrapper .wrap_line(&[LineFragment::text("aaa aaaaaaaaaaaaaaaaaa")], px(72.0)) .collect::>(), &[ Boundary::new(4, 0), Boundary::new(11, 0), Boundary::new(18, 0) ], ); assert_eq!( wrapper .wrap_line(&[LineFragment::text(" aaaaaaa")], px(72.)) .collect::>(), &[ Boundary::new(7, 5), Boundary::new(9, 5), Boundary::new(11, 5), ] ); assert_eq!( wrapper .wrap_line( &[LineFragment::text(" ")], px(72.) ) .collect::>(), &[ Boundary::new(7, 0), Boundary::new(14, 0), Boundary::new(21, 0) ] ); assert_eq!( wrapper .wrap_line(&[LineFragment::text(" aaaaaaaaaaaaaa")], px(72.)) .collect::>(), &[ Boundary::new(7, 0), Boundary::new(14, 3), Boundary::new(18, 3), Boundary::new(22, 3), ] ); // Test wrapping multiple text fragments assert_eq!( wrapper .wrap_line( &[ LineFragment::text("aa bbb "), LineFragment::text("cccc ddddd eeee") ], px(72.) ) .collect::>(), &[ Boundary::new(7, 0), Boundary::new(12, 0), Boundary::new(18, 0) ], ); // Test wrapping with a mix of text and element fragments assert_eq!( wrapper .wrap_line( &[ LineFragment::text("aa "), LineFragment::element(px(20.), 1), LineFragment::text(" bbb "), LineFragment::element(px(30.), 1), LineFragment::text(" cccc") ], px(72.) ) .collect::>(), &[ Boundary::new(5, 0), Boundary::new(9, 0), Boundary::new(11, 0) ], ); // Test with element at the beginning and text afterward assert_eq!( wrapper .wrap_line( &[ LineFragment::element(px(50.), 1), LineFragment::text(" aaaa bbbb cccc dddd") ], px(72.) ) .collect::>(), &[ Boundary::new(2, 0), Boundary::new(7, 0), Boundary::new(12, 0), Boundary::new(17, 0) ], ); // Test with a large element that forces wrapping by itself assert_eq!( wrapper .wrap_line( &[ LineFragment::text("short text "), LineFragment::element(px(100.), 1), LineFragment::text(" more text") ], px(72.) ) .collect::>(), &[ Boundary::new(6, 0), Boundary::new(11, 0), Boundary::new(12, 0), Boundary::new(18, 0) ], ); } #[test] fn test_truncate_line() { let mut wrapper = build_wrapper(); fn perform_test( wrapper: &mut LineWrapper, text: &'static str, result: &'static str, ellipsis: &str, ) { let dummy_run_lens = vec![text.len()]; let mut dummy_runs = generate_test_runs(&dummy_run_lens); assert_eq!( wrapper.truncate_line(text.into(), px(220.), ellipsis, &mut dummy_runs), result ); assert_eq!(dummy_runs.first().unwrap().len, result.len()); } perform_test( &mut wrapper, "aa bbb cccc ddddd eeee ffff gggg", "aa bbb cccc ddddd eeee", "", ); perform_test( &mut wrapper, "aa bbb cccc ddddd eeee ffff gggg", "aa bbb cccc ddddd eee…", "…", ); perform_test( &mut wrapper, "aa bbb cccc ddddd eeee ffff gggg", "aa bbb cccc dddd......", "......", ); } #[test] fn test_truncate_multiple_runs() { let mut wrapper = build_wrapper(); fn perform_test( wrapper: &mut LineWrapper, text: &'static str, result: &str, run_lens: &[usize], result_run_len: &[usize], line_width: Pixels, ) { let mut dummy_runs = generate_test_runs(run_lens); assert_eq!( wrapper.truncate_line(text.into(), line_width, "…", &mut dummy_runs), result ); for (run, result_len) in dummy_runs.iter().zip(result_run_len) { assert_eq!(run.len, *result_len); } } // Case 0: Normal // Text: abcdefghijkl // Runs: Run0 { len: 12, ... } // // Truncate res: abcd… (truncate_at = 4) // Run res: Run0 { string: abcd…, len: 7, ... } perform_test(&mut wrapper, "abcdefghijkl", "abcd…", &[12], &[7], px(50.)); // Case 1: Drop some runs // Text: abcdefghijkl // Runs: Run0 { len: 4, ... }, Run1 { len: 4, ... }, Run2 { len: 4, ... } // // Truncate res: abcdef… (truncate_at = 6) // Runs res: Run0 { string: abcd, len: 4, ... }, Run1 { string: ef…, len: // 5, ... } perform_test( &mut wrapper, "abcdefghijkl", "abcdef…", &[4, 4, 4], &[4, 5], px(70.), ); // Case 2: Truncate at start of some run // Text: abcdefghijkl // Runs: Run0 { len: 4, ... }, Run1 { len: 4, ... }, Run2 { len: 4, ... } // // Truncate res: abcdefgh… (truncate_at = 8) // Runs res: Run0 { string: abcd, len: 4, ... }, Run1 { string: efgh, len: // 4, ... }, Run2 { string: …, len: 3, ... } perform_test( &mut wrapper, "abcdefghijkl", "abcdefgh…", &[4, 4, 4], &[4, 4, 3], px(90.), ); } #[test] fn test_update_run_after_truncation() { fn perform_test(result: &str, run_lens: &[usize], result_run_lens: &[usize]) { let mut dummy_runs = generate_test_runs(run_lens); update_runs_after_truncation(result, "…", &mut dummy_runs); for (run, result_len) in dummy_runs.iter().zip(result_run_lens) { assert_eq!(run.len, *result_len); } } // Case 0: Normal // Text: abcdefghijkl // Runs: Run0 { len: 12, ... } // // Truncate res: abcd… (truncate_at = 4) // Run res: Run0 { string: abcd…, len: 7, ... } perform_test("abcd…", &[12], &[7]); // Case 1: Drop some runs // Text: abcdefghijkl // Runs: Run0 { len: 4, ... }, Run1 { len: 4, ... }, Run2 { len: 4, ... } // // Truncate res: abcdef… (truncate_at = 6) // Runs res: Run0 { string: abcd, len: 4, ... }, Run1 { string: ef…, len: // 5, ... } perform_test("abcdef…", &[4, 4, 4], &[4, 5]); // Case 2: Truncate at start of some run // Text: abcdefghijkl // Runs: Run0 { len: 4, ... }, Run1 { len: 4, ... }, Run2 { len: 4, ... } // // Truncate res: abcdefgh… (truncate_at = 8) // Runs res: Run0 { string: abcd, len: 4, ... }, Run1 { string: efgh, len: // 4, ... }, Run2 { string: …, len: 3, ... } perform_test("abcdefgh…", &[4, 4, 4], &[4, 4, 3]); } #[test] fn test_is_word_char() { #[track_caller] fn assert_word(word: &str) { for c in word.chars() { assert!(LineWrapper::is_word_char(c), "assertion failed for '{}'", c); } } #[track_caller] fn assert_not_word(word: &str) { let found = word.chars().any(|c| !LineWrapper::is_word_char(c)); assert!(found, "assertion failed for '{}'", word); } assert_word("Hello123"); assert_word("non-English"); assert_word("var_name"); assert_word("123456"); assert_word("3.1415"); assert_word("10^2"); assert_word("1~2"); assert_word("100%"); assert_word("@mention"); assert_word("#hashtag"); assert_word("$variable"); assert_word("more⋯"); // Space assert_not_word("foo bar"); // URL case assert_word("https://github.com/zed-industries/zed/"); assert_word("github.com"); assert_word("a=1&b=2"); // Latin-1 Supplement assert_word("ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏ"); // Latin Extended-A assert_word("ĀāĂăĄąĆćĈĉĊċČčĎď"); // Latin Extended-B assert_word("ƀƁƂƃƄƅƆƇƈƉƊƋƌƍƎƏ"); // Cyrillic assert_word("АБВГДЕЖЗИЙКЛМНОП"); // non-word characters assert_not_word("你好"); assert_not_word("안녕하세요"); assert_not_word("こんにちは"); assert_not_word("😀😁😂"); assert_not_word("()[]{}<>"); } // For compatibility with the test macro #[cfg(target_os = "macos")] use crate as gpui; // These seem to vary wildly based on the text system. #[cfg(target_os = "macos")] #[crate::test] fn test_wrap_shaped_line(cx: &mut TestAppContext) { cx.update(|cx| { let text_system = WindowTextSystem::new(cx.text_system().clone()); let normal = TextRun { len: 0, font: font("Helvetica"), color: Default::default(), underline: Default::default(), strikethrough: None, background_color: None, }; let bold = TextRun { len: 0, font: font("Helvetica").bold(), color: Default::default(), underline: Default::default(), strikethrough: None, background_color: None, }; let text = "aa bbb cccc ddddd eeee".into(); let lines = text_system .shape_text( text, px(16.), &[ normal.with_len(4), bold.with_len(5), normal.with_len(6), bold.with_len(1), normal.with_len(7), ], Some(px(72.)), None, ) .unwrap(); assert_eq!( lines[0].layout.wrap_boundaries(), &[ WrapBoundary { run_ix: 0, glyph_ix: 7 }, WrapBoundary { run_ix: 0, glyph_ix: 12 }, WrapBoundary { run_ix: 0, glyph_ix: 18 } ], ); }); } }