fix: various newline handling improvements

src/text/line.rs

@@ -1397,6 +1397,13 @@ mod tests {
             line.render_ref(buf.area, &mut buf);
             assert_eq!(buf, Buffer::with_lines([expected]));
         }
+
+        #[test]
+        fn render_with_newlines() {
+            let mut buf = Buffer::empty(Rect::new(0, 0, 11, 1));
+            Line::from("Hello\nworld!").render(Rect::new(0, 0, 11, 1), &mut buf);
+            assert_eq!(buf, Buffer::with_lines(["Helloworld!"]));
+        }
     }
 
     mod iterators {

src/text/span.rs

@@ -439,7 +439,10 @@ impl<T: fmt::Display> ToSpan for T {
 
 impl fmt::Display for Span<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Display::fmt(&self.content, f)
+        for line in self.content.lines() {
+            fmt::Display::fmt(line, f)?;
+        }
+        Ok(())
     }
 }
 
@@ -562,6 +565,8 @@ mod tests {
         assert_eq!(Span::raw("").width(), 0);
         assert_eq!(Span::raw("test").width(), 4);
         assert_eq!(Span::raw("test content").width(), 12);
+        // Needs reconsideration: https://github.com/ratatui-org/ratatui/issues/1271
+        assert_eq!(Span::raw("test\ncontent").width(), 12);
     }
 
     #[test]
@@ -575,13 +580,20 @@ mod tests {
         assert_eq!(stylized.content, Cow::Borrowed("test content"));
         assert_eq!(stylized.style, Style::new().green().on_yellow().bold());
     }
+
     #[test]
     fn display_span() {
         let span = Span::raw("test content");
         assert_eq!(format!("{span}"), "test content");
         assert_eq!(format!("{span:.4}"), "test");
     }
 
+    #[test]
+    fn display_newline_span() {
+        let span = Span::raw("test\ncontent");
+        assert_eq!(format!("{span}"), "testcontent");
+    }
+
     #[test]
     fn display_styled_span() {
         let stylized_span = Span::styled("stylized test content", Style::new().green());
@@ -757,6 +769,14 @@ mod tests {
                 [Cell::new("a"), Cell::new("b"), Cell::new("c\u{200B}")]
             );
         }
+
+        #[test]
+        fn render_with_newlines() {
+            let span = Span::raw("a\nb");
+            let mut buf = Buffer::empty(Rect::new(0, 0, 2, 1));
+            span.render(buf.area, &mut buf);
+            assert_eq!(buf.content(), [Cell::new("a"), Cell::new("b")]);
+        }
     }
 
     /// Regression test for <https://github.com/ratatui-org/ratatui/issues/1160> One line contains

src/widgets/chart.rs

@@ -1,7 +1,6 @@
 use std::cmp::max;
 
 use strum::{Display, EnumString};
-use unicode_width::UnicodeWidthStr;
 
 use crate::{
     layout::Flex,
@@ -817,7 +816,7 @@ impl<'a> Chart<'a> {
             .as_ref()
             .and_then(|labels| labels.first())
         {
-            let first_label_width = first_x_label.content.width() as u16;
+            let first_label_width = first_x_label.width() as u16;
             let width_left_of_y_axis = match self.x_axis.labels_alignment {
                 Alignment::Left => {
                     // The last character of the label should be below the Y-Axis when it exists,