feat: handle small screen size

- Prevent crashes when terminal size shrinks too small
- Display notice to resize screen

src/ui/audio_graph.rs

@@ -1,10 +1,10 @@
-use ratatui::{
-    buffer::Buffer,
-    layout::Rect,
-    style::Style,
-    symbols::Marker,
-    widgets::{Axis, Chart, Dataset, GraphType, StatefulWidget, Widget},
-};
+use ratatui::buffer::Buffer;
+use ratatui::layout::{Alignment, Rect};
+use ratatui::style::{Modifier, Style, Stylize};
+use ratatui::symbols::Marker;
+use ratatui::text::Line;
+use ratatui::widgets::Paragraph;
+use ratatui::widgets::{Axis, Chart, Dataset, GraphType, StatefulWidget, Widget};
 
 use super::app_color;
 use super::utils;
@@ -31,6 +31,32 @@ impl StatefulWidget for AudioGraph {
             return;
         }
 
+        // The graph is optional, omit it if there's not enough space
+        if area.height < 4 {
+            return;
+        }
+
+        if area.height < 8 {
+            let mut rect = Rect {
+                x: 0,
+                y: 0,
+                width: area.width,
+                height: 3,
+            };
+
+            utils::center_rect_in_container(&mut rect, &area);
+
+            let paragraph = Paragraph::new(vec![
+                Line::from("Your terminal size is too small"),
+                Line::from("Resize to see the graph"),
+            ])
+            .alignment(Alignment::Center)
+            .style(Style::default().fg(*app_color::TEXT_LIGHT))
+            .add_modifier(Modifier::BOLD);
+
+            return paragraph.render(rect, buf);
+        }
+
         let dataset = normalize(&state.dataset);
 
         let datasets = vec![Dataset::default()

src/ui/insufficient_size_notice.rs

@@ -0,0 +1,46 @@
+use ratatui::buffer::Buffer;
+use ratatui::layout::Alignment;
+use ratatui::layout::Rect;
+use ratatui::style::{Modifier, Style, Stylize};
+use ratatui::text::Line;
+use ratatui::widgets::Widget;
+use ratatui::widgets::{Block, BorderType, Borders, Paragraph};
+
+use super::{app_color, utils};
+
+#[derive(Clone, Copy)]
+pub struct InsufficientSizeNotice;
+
+impl InsufficientSizeNotice {
+    pub fn new() -> Self {
+        Self {}
+    }
+}
+
+impl Widget for InsufficientSizeNotice {
+    fn render(self, area: Rect, buf: &mut Buffer) {
+        let mut rect = Rect {
+            x: 0,
+            y: 0,
+            width: area.width,
+            height: 3,
+        };
+
+        utils::center_rect_in_container(&mut rect, &area);
+
+        let block = Block::default()
+            .borders(Borders::ALL)
+            .border_type(BorderType::Rounded)
+            .border_style(Style::default().fg(*app_color::BORDER));
+
+        let paragraph = Paragraph::new(vec![
+            Line::from("Your terminal size is too small"),
+            Line::from("Please resize to use the app"),
+        ])
+        .alignment(Alignment::Center)
+        .add_modifier(Modifier::BOLD);
+
+        block.render(area, buf);
+        paragraph.render(rect, buf);
+    }
+}

src/ui/mod.rs

@@ -13,6 +13,7 @@ use super::AppEvent;
 use app_state::AppState;
 use audio_graph::AudioGraph;
 use instructions::Instruction;
+use insufficient_size_notice::InsufficientSizeNotice;
 use tuning_bar::TuningBar;
 use tuning_notes::TuningNotes;
 use tuning_pegs::TuningPegs;
@@ -21,6 +22,7 @@ mod app_color;
 mod app_state;
 mod audio_graph;
 mod instructions;
+mod insufficient_size_notice;
 mod loading_icon;
 mod tuning_bar;
 mod tuning_notes;
@@ -32,6 +34,9 @@ pub static mut FRAME_COUNT: usize = 0;
 // In cents. 100 cents is 1 semitone
 pub const IN_TUNE_RANGE: f64 = 8.0;
 
+pub const MIN_REQUIRED_WIDTH: u16 = 90;
+pub const MIN_REQUIRED_HEIGHT: u16 = 35;
+
 pub fn render(event_stream: Receiver<AppEvent>) -> Result<()> {
     // startup: Enable raw mode for the terminal, giving us fine control over user input
     crossterm::terminal::enable_raw_mode()?;
@@ -47,13 +52,21 @@ pub fn render(event_stream: Receiver<AppEvent>) -> Result<()> {
                 FRAME_COUNT += 1;
             }
 
+            let frame_rect = f.size();
+
+            if frame_rect.width < MIN_REQUIRED_WIDTH || frame_rect.height < MIN_REQUIRED_HEIGHT {
+                let notice = InsufficientSizeNotice::new();
+                f.render_widget(notice, f.size());
+                return;
+            }
+
             let [tuning_strings_rect, instructions_rect, tuning_bar_rect, graph_rect] =
-                calculate_layout(f.size());
+                calculate_layout(frame_rect);
 
             // Background
             f.render_widget(
                 Block::default().style(Style::default().bg(*app_color::BACKGROUND_DARK)),
-                f.size(),
+                frame_rect,
             );
 
             f.render_widget(