Kilo Text Editor - A Terminal-Based Text Editor in C

Demo Video

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Project Overview

Kilo is a small terminal-based text editor written entirely in C. This project demonstrates the fundamentals of building a text editor from scratch, implementing features like raw mode terminal handling, cursor movement, file I/O, text Highlighting and text manipulation operations. The Text Editor has all the basic Features of a Normal Text Editor and a feature of code editor like syntax Highlighting for c or cpp files.I will try to add Undo/Redo Feature in future.

Key Features

Editing Features

• Full Text Editing: Insert, delete, and modify text with complete character support
• Multi-line Support: Handle files with unlimited number of lines
• Cursor Navigation: Arrow key navigation with proper line wrapping
• File Operations: Open, save, and create new files with unsaved changes protection
• Status Bar: Display filename, line count, cursor position, and modification status
• Message Bar: Show temporary status messages and prompts

Advanced Functionality

• Smart Scrolling: Viewport scrolling for files larger than terminal size
• Tab Rendering: Proper tab character handling with configurable tab stops (8 spaces)
• Line Wrapping: Intelligent cursor movement across line boundaries
• Memory Management: Dynamic memory allocation for efficient file handling
• Raw Mode Terminal: Complete control over terminal input/output
• Cross-platform: Works on Unix/Linux systems with termios support

Keyboard Shortcuts

• Ctrl+Q: Quit editor (with unsaved changes warning)
• Ctrl+S: Save file (prompts for filename if new file)
• Arrow Keys: Navigate cursor in all directions
• Page Up/Down: Scroll by screen height
• Home/End: Jump to beginning/end of line
• Backspace/Delete: Remove characters
• Enter: Create new line
• ESC: Cancel current operation

Key Modules

• Terminal Management: Raw mode setup, cursor positioning, screen clearing
• Input Processing: Keyboard input handling, special key sequences
• Display Engine: Screen rendering, scrolling, status bars
• File Operations: Loading, saving, and managing text files
• Text Manipulation: Insertion, deletion, and modification operations

🔧 Technical Features

• Raw Terminal Mode: Bypasses shell processing for direct key handling
• ANSI Escape Sequences: Uses VT100 compatible codes for cursor control
• Dynamic Memory Management: Efficiently handles files of varying sizes
• Buffer-based Rendering: Minimizes screen flicker with buffered output
• Cross-platform Compatibility: Works on any POSIX-compliant system

Normal Usage

Navigation

• Arrow Keys: Move cursor up, down, left, right
• Page Up/Down: Scroll by full screen
• Home: Jump to beginning of current line
• End: Jump to end of current line

Editing

• Character Press: Insert characters at cursor position
• Enter: Create new line and move cursor down
• Backspace: Delete character to the left of cursor
• Delete: Delete character at cursor position

File Operations

• Ctrl+S: Save current file
  • If new file: prompts for filename
  • Shows "X bytes written to disk" on success
• Ctrl+Q: Quit editor
  • Warns if unsaved changes exist
  • Requires 3 consecutive Ctrl+Q presses to force quit

Interface Elements

• Status Bar: Shows filename, line count, modification status, cursor position
• Message Bar: Displays temporary messages and prompts
• Welcome Screen: Shows version info when no file is loaded

Some Advanced Features

Tab Handling

• Tabs are rendered as spaces (default: 8 spaces)
• Configurable via TAB_STOP constant
• Proper cursor positioning with tab alignment

Scrolling System

• Automatic scrolling when cursor moves beyond screen boundaries
• Horizontal and vertical scrolling support
• Smooth viewport management for large files

Memory Management

• Dynamic allocation for text rows
• Efficient reallocation when inserting/deleting lines
• Automatic cleanup on exit