Merge pull request #32 from pm100/password

Allow masking a text with a specific character

Cargo.toml

@@ -63,6 +63,10 @@ required-features = ["crossterm"]
 name = "single_line"
 required-features = ["crossterm"]
 
+[[example]]
+name = "password"
+required-features = ["crossterm"]
+
 [[example]]
 name = "variable"
 required-features = ["crossterm"]

examples/password.rs

@@ -0,0 +1,62 @@
+use crossterm::event::{DisableMouseCapture, EnableMouseCapture};
+use crossterm::terminal::{
+    disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen,
+};
+use std::io;
+use tui::backend::CrosstermBackend;
+use tui::layout::{Constraint, Layout};
+use tui::style::{Color, Style};
+use tui::widgets::{Block, Borders};
+use tui::Terminal;
+use tui_textarea::{Input, Key, TextArea};
+
+fn main() -> io::Result<()> {
+    let stdout = io::stdout();
+    let mut stdout = stdout.lock();
+
+    enable_raw_mode()?;
+    crossterm::execute!(stdout, EnterAlternateScreen, EnableMouseCapture)?;
+    let backend = CrosstermBackend::new(stdout);
+    let mut term = Terminal::new(backend)?;
+
+    let mut textarea = TextArea::default();
+    textarea.set_cursor_line_style(Style::default());
+    textarea.set_mask_char('\u{2022}'); //U+2022 BULLET (•)
+    textarea.set_placeholder_text("Please enter your password");
+    let layout =
+        Layout::default().constraints([Constraint::Length(3), Constraint::Min(1)].as_slice());
+    textarea.set_style(Style::default().fg(Color::LightGreen));
+    textarea.set_block(Block::default().borders(Borders::ALL).title("Password"));
+    loop {
+        term.draw(|f| {
+            let chunks = layout.split(f.size());
+            let widget = textarea.widget();
+            f.render_widget(widget, chunks[0]);
+        })?;
+
+        match crossterm::event::read()?.into() {
+            Input { key: Key::Esc, .. } => break,
+            Input {
+                key: Key::Enter, ..
+            } => break,
+
+            input => {
+                // TextArea::input returns if the input modified its text
+                if textarea.input(input) {
+                    //  is_valid = validate(&mut textarea);
+                }
+            }
+        }
+    }
+
+    disable_raw_mode()?;
+    crossterm::execute!(
+        term.backend_mut(),
+        LeaveAlternateScreen,
+        DisableMouseCapture
+    )?;
+    term.show_cursor()?;
+
+    println!("Input: {:?}", textarea.lines()[0]);
+    Ok(())
+}

src/highlight.rs

@@ -5,13 +5,15 @@ use crate::tui::style::Style;
     feature = "ratatui-your-backend",
 ))]
 use crate::tui::text::Line as Spans;
+
 use crate::tui::text::Span;
 #[cfg(not(any(
     feature = "ratatui-crossterm",
     feature = "ratatui-termion",
     feature = "ratatui-your-backend",
 )))]
 use crate::tui::text::Spans;
+
 use crate::util::{num_digits, spaces};
 use std::borrow::Cow;
 use std::cmp::Ordering;
@@ -46,27 +48,39 @@ impl Boundary {
     }
 }
 
-fn replace_tabs(s: &str, tab_len: u8) -> Cow<'_, str> {
-    let tab = spaces(tab_len);
-    let mut buf = String::new();
-    for (i, c) in s.char_indices() {
-        if buf.is_empty() {
-            if c == '\t' {
-                buf.reserve(s.len());
-                buf.push_str(&s[..i]);
-                buf.push_str(tab);
+fn prepare_line(s: &str, tab_len: u8, mask: Option<char>) -> Cow<'_, str> {
+    // two tasks performed here
+    // - mask out chars if mask is Some
+    // - replace hard tabs by the correct number of spaces
+    //   (soft tabs were done earlier in 'insert_tab')
+    match mask {
+        Some(ch) => {
+            // no tab processing in the mask case
+            return Cow::Owned(s.chars().map(|_| ch).collect());
+        }
+        None => {
+            let tab = spaces(tab_len);
+            let mut buf = String::new();
+            for (i, c) in s.char_indices() {
+                if buf.is_empty() {
+                    if c == '\t' {
+                        buf.reserve(s.len());
+                        buf.push_str(&s[..i]);
+                        buf.push_str(tab);
+                    }
+                } else if c == '\t' {
+                    buf.push_str(tab);
+                } else {
+                    buf.push(c);
+                }
+            }
+            if !buf.is_empty() {
+                return Cow::Owned(buf);
             }
-        } else if c == '\t' {
-            buf.push_str(tab);
-        } else {
-            buf.push(c);
         }
-    }
-    if buf.is_empty() {
-        Cow::Borrowed(s)
-    } else {
-        Cow::Owned(buf)
-    }
+    };
+    // drop through in the case of no mask and no tabs
+    return Cow::Borrowed(s);
 }
 
 pub struct LineHighlighter<'a> {
@@ -119,7 +133,7 @@ impl<'a> LineHighlighter<'a> {
         }
     }
 
-    pub fn into_spans(self) -> Spans<'a> {
+    pub fn into_spans(self, mask: Option<char>) -> Spans<'a> {
         let Self {
             line,
             mut spans,
@@ -131,7 +145,7 @@ impl<'a> LineHighlighter<'a> {
         } = self;
 
         if boundaries.is_empty() {
-            spans.push(Span::styled(replace_tabs(line, tab_len), style_begin));
+            spans.push(Span::styled(prepare_line(line, tab_len, mask), style_begin));
             if cursor_at_end {
                 spans.push(Span::styled(" ", cursor_style));
             }
@@ -152,7 +166,7 @@ impl<'a> LineHighlighter<'a> {
             if let Some((next_boundary, end)) = boundaries.next() {
                 if start < end {
                     spans.push(Span::styled(
-                        replace_tabs(&line[start..end], tab_len),
+                        prepare_line(&line[start..end], tab_len, mask),
                         style,
                     ));
                 }
@@ -166,7 +180,10 @@ impl<'a> LineHighlighter<'a> {
                 start = end;
             } else {
                 if start != line.len() {
-                    spans.push(Span::styled(replace_tabs(&line[start..], tab_len), style));
+                    spans.push(Span::styled(
+                        prepare_line(&line[start..], tab_len, mask),
+                        style,
+                    ));
                 }
                 if cursor_at_end {
                     spans.push(Span::styled(" ", cursor_style));

src/textarea.rs

@@ -63,6 +63,7 @@ pub struct TextArea<'a> {
     alignment: Alignment,
     pub(crate) placeholder: String,
     pub(crate) placeholder_style: Style,
+    mask: Option<char>,
 }
 
 /// Convert any iterator whose elements can be converted into [`String`] into [`TextArea`]. Each [`String`] element is
@@ -162,6 +163,7 @@ impl<'a> TextArea<'a> {
             alignment: Alignment::Left,
             placeholder: String::new(),
             placeholder_style: Style::default().fg(Color::DarkGray),
+            mask: None,
         }
     }
 
@@ -1005,7 +1007,7 @@ impl<'a> TextArea<'a> {
             hl.search(matches, self.search.style);
         }
 
-        hl.into_spans()
+        hl.into_spans(self.mask)
     }
 
     /// Build a tui-rs widget to render the current state of the textarea. The widget instance returned from this
@@ -1304,6 +1306,18 @@ impl<'a> TextArea<'a> {
         }
     }
 
+    /// Specifies that the text should be masked with the specified character
+    ///
+    pub fn set_mask_char(&mut self, mask: char) {
+        self.mask = Some(mask);
+    }
+
+    /// Clear the previously set masking character
+    ///
+    pub fn clear_mask_char(&mut self) {
+        self.mask = None;
+    }
+
     /// Set the style of cursor. By default, a cursor is rendered in the reversed color. Setting the same style as
     /// cursor line hides a cursor.
     /// ```