scrolling part 1

Kacperacy · May 14, 2024 · 5740316 · 5740316
1 parent 4b14d83
commit 5740316
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Showing 4 changed files with 58 additions and 17 deletions.
diff --git a/src/app.rs b/src/app.rs
@@ -1,5 +1,7 @@
 use std::error;
 
+use ratatui::layout::Rect;
+
 pub type AppResult<T> = std::result::Result<T, Box<dyn error::Error>>;
 
 #[derive(Debug)]
@@ -21,6 +23,7 @@ pub struct App {
     pub cursor_position: Position,
     pub cursor_offset: Position,
     pub opened_filename: String,
+    pub window_size: Rect,
 }
 
 impl Default for App {
@@ -31,6 +34,7 @@ impl Default for App {
             cursor_position: Position { x: 0, y: 0 },
             cursor_offset: Position { x: 0, y: 0 },
             opened_filename: String::new(),
+            window_size: Rect::new(0, 0, 0, 0),
         }
     }
 }
@@ -50,11 +54,14 @@ impl App {
         while self.cursor_position.y >= self.content.len() {
             self.content.push(String::new());
         }
-        self.content[self.cursor_position.y].insert(self.cursor_position.x, c);
+        self.content[self.cursor_position.y + self.cursor_offset.y]
+            .insert(self.cursor_position.x + self.cursor_offset.x, c);
         self.cursor_position.x += 1;
     }
 
     pub fn add_new_line(&mut self) {
+        self.content
+            .insert(self.cursor_position.y + self.cursor_offset.y, String::new());
         self.cursor_position.y += 1;
         self.cursor_position.x = 0;
     }
@@ -68,23 +75,43 @@ impl App {
     }
 
     pub fn move_cursor(&mut self, direction: Direction) {
-        if direction.x < 0 && self.cursor_position.x > 0 {
-            self.cursor_position.x -= 1;
+        if direction.x < 0 && self.cursor_position.x + self.cursor_offset.x > 0 {
+            if self.cursor_position.x == 0 {
+                self.cursor_offset.x -= 1;
+            } else {
+                self.cursor_position.x -= 1;
+            }
         } else if direction.x > 0 {
             if let Some(line) = self.content.get(self.cursor_position.y) {
-                if line.len() > self.cursor_position.x {
-                    self.cursor_position.x += 1;
+                if line.len() > self.cursor_position.x + self.cursor_offset.x {
+                    if self.window_size.width.saturating_sub(1) > self.cursor_position.x as u16 {
+                        self.cursor_position.x += 1;
+                    } else {
+                        self.cursor_offset.x += 1;
+                    }
                 }
             }
         }
 
-        if direction.y > 0 && self.cursor_position.y > 0 {
-            self.cursor_position.y -= 1;
+        if direction.y > 0 && self.cursor_position.y + self.cursor_offset.y > 0 {
+            if self.cursor_position.y == 0 {
+                self.cursor_offset.y -= 1;
+            } else {
+                self.cursor_position.y -= 1;
+            }
+
             if self.cursor_position.x > self.content[self.cursor_position.y].len() {
                 self.cursor_position.x = self.content[self.cursor_position.y].len();
             }
-        } else if direction.y < 0 && self.cursor_position.y < self.content.len().saturating_sub(1) {
-            self.cursor_position.y += 1;
+        } else if direction.y < 0
+            && self.cursor_position.y + self.cursor_offset.y < self.content.len().saturating_sub(1)
+        {
+            if self.window_size.height.saturating_sub(4) > self.cursor_position.y as u16 {
+                self.cursor_position.y += 1;
+            } else {
+                self.cursor_offset.y += 1;
+            }
+
             if self.cursor_position.x > self.content[self.cursor_position.y].len() {
                 self.cursor_position.x = self.content[self.cursor_position.y].len();
             }

diff --git a/src/main.rs b/src/main.rs
@@ -14,6 +14,7 @@ async fn main() -> AppResult<()> {
     let events = EventHandler::new(250);
     let mut tui = Tui::new(terminal, events);
     tui.init()?;
+    app.window_size = tui.get_terminal_size()?;
     tui.draw(&mut app)?;
 
     while app.running {
@@ -24,7 +25,10 @@ async fn main() -> AppResult<()> {
                 tui.draw(&mut app)?;
             }
             Event::Mouse(_) => tui.draw(&mut app)?,
-            Event::Resize(_, _) => tui.draw(&mut app)?,
+            Event::Resize(_, _) => {
+                app.window_size = tui.get_terminal_size()?;
+                tui.draw(&mut app)?;
+            }
         }
     }
 

diff --git a/src/tui.rs b/src/tui.rs
@@ -4,8 +4,9 @@ use crate::ui;
 use crossterm::event::{DisableMouseCapture, EnableMouseCapture};
 use crossterm::terminal::{self, EnterAlternateScreen, LeaveAlternateScreen};
 use ratatui::backend::Backend;
+use ratatui::layout::Rect;
 use ratatui::Terminal;
-use std::io;
+use std::io::{self, Error};
 use std::panic;
 
 #[derive(Debug)]
@@ -52,4 +53,8 @@ impl<B: Backend> Tui<B> {
         self.terminal.show_cursor()?;
         Ok(())
     }
+
+    pub fn get_terminal_size(&self) -> Result<Rect, Error> {
+        self.terminal.size()
+    }
 }
diff --git a/src/ui.rs b/src/ui.rs
@@ -18,7 +18,7 @@ pub fn render(app: &mut App, frame: &mut Frame) {
     let cursor_position_status = Line::from(format!(
         " {:>2}:{:<2} ",
         app.cursor_position.y + 1,
-        app.cursor_position.x + 1
+        app.cursor_position.x + 1,
     ))
     .right_aligned()
     .style(Style::default().bg(Color::Rgb(128, 192, 255)).bold());
@@ -29,6 +29,7 @@ pub fn render(app: &mut App, frame: &mut Frame) {
             Constraint::Length(1),
             Constraint::Min(0),
             Constraint::Length(1),
+            Constraint::Length(1),
         ])
         .split(frame.size());
 
@@ -52,11 +53,13 @@ pub fn render(app: &mut App, frame: &mut Frame) {
     );
 
     frame.render_widget(
-        Paragraph::new(content_lines).style(
-            Style::default()
-                .fg(Color::Rgb(128, 192, 255))
-                .bg(Color::Rgb(32, 32, 64)),
-        ),
+        Paragraph::new(content_lines)
+            .style(
+                Style::default()
+                    .fg(Color::Rgb(128, 192, 255))
+                    .bg(Color::Rgb(32, 32, 64)),
+            )
+            .scroll((app.cursor_offset.y as u16, app.cursor_offset.x as u16)),
         layout[1],
     );
 
@@ -78,6 +81,8 @@ pub fn render(app: &mut App, frame: &mut Frame) {
         status_bar_layout[1],
     );
 
+    frame.render_widget(Line::from("Press Ctrl + C to quit").centered(), layout[3]);
+
     frame.set_cursor(
         app.cursor_position.x as u16,
         app.cursor_position.y as u16 + 1,