refactor: define struct WrappedLine instead of anonymous tuple (#608)

It makes the type easier to document, and more obvious for users

src/widgets/paragraph.rs

@@ -6,7 +6,7 @@ use crate::{
     style::{Style, Styled},
     text::{StyledGrapheme, Text},
     widgets::{
-        reflow::{LineComposer, LineTruncator, WordWrapper},
+        reflow::{LineComposer, LineTruncator, WordWrapper, WrappedLine},
         Block, Widget,
     },
 };
@@ -254,8 +254,11 @@ impl<'a> Widget for Paragraph<'a> {
 impl<'a> Paragraph<'a> {
     fn render_text<C: LineComposer<'a>>(&self, mut composer: C, area: Rect, buf: &mut Buffer) {
         let mut y = 0;
-        while let Some((current_line, current_line_width, current_line_alignment)) =
-            composer.next_line()
+        while let Some(WrappedLine {
+            line: current_line,
+            width: current_line_width,
+            alignment: current_line_alignment,
+        }) = composer.next_line()
         {
             if y >= self.scroll.0 {
                 let mut x = get_line_offset(current_line_width, area.width, current_line_alignment);

src/widgets/reflow.rs

@@ -11,7 +11,16 @@ const NBSP: &str = "\u{00a0}";
 /// Cannot implement it as Iterator since it yields slices of the internal buffer (need streaming
 /// iterators for that).
 pub trait LineComposer<'a> {
-    fn next_line(&mut self) -> Option<(&[StyledGrapheme<'a>], u16, Alignment)>;
+    fn next_line<'lend>(&'lend mut self) -> Option<WrappedLine<'lend, 'a>>;
+}
+
+pub struct WrappedLine<'lend, 'text> {
+    /// One line reflowed to the correct width
+    pub line: &'lend [StyledGrapheme<'text>],
+    /// The width of the line
+    pub width: u16,
+    /// Whether the line was aligned left or right
+    pub alignment: Alignment,
 }
 
 /// A state machine that wraps lines on word boundaries.
@@ -56,7 +65,7 @@ where
     O: Iterator<Item = (I, Alignment)>,
     I: Iterator<Item = StyledGrapheme<'a>>,
 {
-    fn next_line(&mut self) -> Option<(&[StyledGrapheme<'a>], u16, Alignment)> {
+    fn next_line<'lend>(&'lend mut self) -> Option<WrappedLine<'lend, 'a>> {
         if self.max_line_width == 0 {
             return None;
         }
@@ -200,7 +209,11 @@ where
 
         if let Some(line) = current_line {
             self.current_line = line;
-            Some((&self.current_line[..], line_width, self.current_alignment))
+            Some(WrappedLine {
+                line: &self.current_line[..],
+                width: line_width,
+                alignment: self.current_alignment,
+            })
         } else {
             None
         }
@@ -249,7 +262,7 @@ where
     O: Iterator<Item = (I, Alignment)>,
     I: Iterator<Item = StyledGrapheme<'a>>,
 {
-    fn next_line(&mut self) -> Option<(&[StyledGrapheme<'a>], u16, Alignment)> {
+    fn next_line<'lend>(&'lend mut self) -> Option<WrappedLine<'lend, 'a>> {
         if self.max_line_width == 0 {
             return None;
         }
@@ -296,11 +309,11 @@ where
         if lines_exhausted {
             None
         } else {
-            Some((
-                &self.current_line[..],
-                current_line_width,
-                current_alignment,
-            ))
+            Some(WrappedLine {
+                line: &self.current_line[..],
+                width: current_line_width,
+                alignment: current_alignment,
+            })
         }
     }
 }
@@ -360,7 +373,12 @@ mod test {
         let mut lines = vec![];
         let mut widths = vec![];
         let mut alignments = vec![];
-        while let Some((styled, width, alignment)) = composer.next_line() {
+        while let Some(WrappedLine {
+            line: styled,
+            width,
+            alignment,
+        }) = composer.next_line()
+        {
             let line = styled
                 .iter()
                 .map(|StyledGrapheme { symbol, .. }| *symbol)