chore: add comments for deps

Cargo.toml

@@ -12,21 +12,34 @@ keywords = ["font", "character", "cli", "utilities"]
 categories = ["command-line-utilities", "text-processing", "visualization"]
 
 [dependencies]
+# Global values
 once_cell = "1"
-httparse = "1"
-crossterm = "0.27"
+
+# Define error type
+thiserror = "1"
+
+# 2D array
+grid = "0.11"
+
+# CLI argument parser
+clap = { version = "4", features = ["derive", "unicode", "wrap_help"] }
+
+# Font loader
 fontdb = "0.16"
+
+# Font parser
 ttf-parser = "0.20"
+
+# Font rasterizer
+# see https://gist.github.com/7sDream/0bb194be42b8cb1f1926ca12151c8d76 for alternatives.
 ab_glyph = "0.2"
-thiserror = "1"
-grid = "0.11"
 
-[dependencies.clap]
-version = "4"
-features = ["derive", "unicode", "wrap_help"]
+# Termianal UI
+ratatui = "0.24"
 
-[dependencies.tui]
-package = "ratatui"
-version = "0.24"
-default-features = false
-features = ["crossterm"]
+# Terminal events
+crossterm = "0.27"
+
+# Home-made singel thread HTTP server for preview fonts in browser.
+# Alternative: output a html file into temp dir and open it
+httparse = "1"

src/preview/terminal/ui/cache.rs

@@ -20,7 +20,7 @@ use std::{collections::HashMap, iter::Iterator};
 
 use grid::Grid;
 use once_cell::sync::Lazy;
-use tui::{
+use ratatui::{
     style::Color,
     widgets::canvas::{Painter, Shape},
 };

src/preview/terminal/ui/mod.rs

@@ -30,7 +30,7 @@ use crossterm::{
     execute,
     terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
 };
-use tui::{
+use ratatui::{
     backend::CrosstermBackend,
     layout::{Alignment, Constraint, Direction, Layout, Rect},
     style::{Color, Modifier, Style},

src/preview/terminal/ui/state.rs

@@ -22,7 +22,7 @@ use std::{
     rc::Rc,
 };
 
-use tui::widgets::ListState;
+use ratatui::widgets::ListState;
 
 use super::cache::{CacheKey, GlyphCache, GlyphCanvasShape, RenderType, CHAR_RENDERS, MONO_RENDER};
 use crate::{