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use {
crate::{Area, CompoundStyle, Error, Event},
std::io::Write,
crossterm::{
cursor,
event::{
KeyCode,
KeyEvent,
},
queue,
style::{
Attribute,
Color,
SetBackgroundColor,
},
},
};
/// A simple input field, managing its cursor position.
pub struct InputField {
content: Vec<char>,
pub area: Area,
cursor_pos: usize, // position in chars
normal_style: CompoundStyle,
cursor_style: CompoundStyle,
pub focused: bool,
}
impl InputField {
pub fn new(area: Area) -> Self {
debug_assert!(area.height == 1, "input area must be of height 1");
let normal_style = CompoundStyle::default();
let mut cursor_style = normal_style.clone();
cursor_style.add_attr(Attribute::Reverse);
let focused = true;
Self {
content: Vec::new(),
area,
cursor_pos: 0,
normal_style,
cursor_style,
focused,
}
}
pub fn change_area(&mut self, x: u16, y: u16, w: u16) {
self.area.left = x;
self.area.top = y;
self.area.width = w;
}
pub fn set_normal_style(&mut self, style: CompoundStyle) {
self.normal_style = style;
self.cursor_style = self.normal_style.clone();
self.cursor_style.add_attr(Attribute::Reverse);
}
pub fn get_content(&self) -> String {
self.content.iter().collect()
}
/// tell whether the content of the input is equal
/// to the argument
pub fn is_content(&self, s: &str) -> bool {
// TODO this comparison could be optimized
let str_content = self.get_content();
str_content == s
}
/// change the content to the new one and
/// put the cursor at the end **if** the
/// content is different from the previous one.
pub fn set_content(&mut self, s: &str) {
if self.is_content(s) {
return;
}
self.content = s.chars().collect();
self.cursor_pos = self.content.len();
}
/// put a char at cursor position (and increments this
/// position)
pub fn put_char(&mut self, c: char) {
self.content.insert(self.cursor_pos, c);
self.cursor_pos += 1;
}
/// remove the char left of the cursor, if any
pub fn del_char_left(&mut self) -> bool {
if self.cursor_pos > 0 {
self.cursor_pos -= 1;
self.content.remove(self.cursor_pos);
true
} else {
false
}
}
/// remove the char at cursor position, if any
pub fn del_char_below(&mut self) -> bool {
if self.cursor_pos < self.content.len() {
self.content.remove(self.cursor_pos);
true
} else {
false
}
}
/// apply a click event
///
/// (for when you handle the events yourselves and don't
/// have a termimad event)
pub fn apply_click_event(&mut self, x: u16, y: u16) -> bool {
if self.area.contains(x, y) {
if self.focused {
let p = (x - 1 - self.area.left) as usize;
self.cursor_pos = p.min(self.content.len());
} else {
self.focused = true;
}
true
} else {
false
}
}
/// apply an event being a key without modifier.
///
/// You don't usually call this function but the more
/// general `apply_event`. This one is useful when you
/// manage events yourselves.
pub fn apply_keycode_event(&mut self, code: KeyCode) -> bool {
if !self.focused {
return false;
}
match code {
KeyCode::Home => {
self.cursor_pos = 0;
true
}
KeyCode::End => {
self.cursor_pos = self.content.len();
true
}
KeyCode::Char(c) => {
self.put_char(c);
true
}
KeyCode::Left if self.cursor_pos > 0 => {
self.cursor_pos -= 1;
true
}
KeyCode::Right if self.cursor_pos < self.content.len() => {
self.cursor_pos += 1;
true
}
KeyCode::Backspace => self.del_char_left(),
KeyCode::Delete => self.del_char_below(),
_ => false,
}
}
/// apply the passed event to change the state (content, cursor)
///
/// Return true when the event was used.
pub fn apply_event(&mut self, event: &Event) -> bool {
match event {
Event::Click(x, y, ..) => {
self.apply_click_event(*x, *y)
}
Event::Key(KeyEvent{code, modifiers}) if modifiers.is_empty() => {
self.apply_keycode_event(*code)
}
_ => false,
}
}
/// render the input field on screen.
///
/// All rendering must be explicitely called, no rendering is
/// done on functions changing the state.
///
/// w is typically either stderr or stdout.
pub fn display_on<W>(&self, w: &mut W) -> Result<(), Error>
where
W: std::io::Write,
{
queue!(w, SetBackgroundColor(Color::Reset))?;
queue!(w, cursor::MoveTo(self.area.left, self.area.top))?;
for (i, c) in self.content.iter().enumerate() {
if self.cursor_pos == i && self.focused {
self.cursor_style.queue(w, c)?;
} else {
self.normal_style.queue(w, c)?;
}
}
let mut e = self.content.len();
if e == self.cursor_pos && self.focused {
self.cursor_style.queue(w, ' ')?;
e += 1;
}
for _ in e..self.area.width as usize {
self.normal_style.queue(w, ' ')?;
}
Ok(())
}
/// render the input field on stdout
pub fn display(&self) -> Result<(), Error> {
let mut w = std::io::stdout();
self.display_on(&mut w)?;
w.flush()?;
Ok(())
}
}