Table of Contents

1. Alterm - Simple SDL2 Terminal Emulator

   • Features

2. Getting Started

   • Prerequisites
   • Bulding Alterm
3. Project Structure
4. Usage
5. Settings Keys
6. License
7. Future Work
8. What I Learned

Alterm - Simple SDL2 Terminal Emulator

Alterm is a lightweight, minimal terminal emulator built using C++ and SDL2. It provides a simple and minimalistic interface for terminal operations, allowing users to execute basic shell commands, navigate directories, and utilize tab-based auto-completion for command and file names. The terminal emulator is designed to be lightweight and easy to use, making it suitable for various applications and environments.

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Features

• PTY Shell Integration: Alterm leverages the POSIX PTY (Pseudo-Terminal) interface to create a virtual terminal, enabling seamless integration with the underlying operating system's shell. This allows Alterm to execute shell commands and interact with the terminal environment as if it were a regular terminal emulator.

• Command History: Alterm maintains a command history, enabling users to easily navigate through previously executed commands using the up and down arrow keys. This feature provides a convenient way to access and reuse previous commands, enhancing productivity.

• SDL2-based UI: Alterm utilizes the SDL2 library to create a graphical user interface (GUI) for the terminal emulator. This GUI provides a visually appealing and interactive experience, allowing users to interact with the terminal in a more intuitive manner.

• Built-in Settings Mode (settings, set, save,exit): Alterm allows users to access and modify its settings using the settings command. This feature provides a convenient way to customize various aspects of the terminal emulator, such as colors, fonts, and other visual elements.

• Custom Font Rendering using SDL_ttf**: Alterm supports custom font rendering using the SDL_ttf library. Users can specify a custom font file and apply it to the terminal emulator's UI, resulting in a visually appealing and tailored appearance.

• Auto-scroll & Scrollback

• Live Cursor With Blinking Effect

ScreenShots

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Getting Started

These instructions will help you build and run alterm.

Prerequisites

Make sure you have the following installed on you system:

• g++ version 11 or higher

• cmake version 3.21 or higher

• SDL2 version 2.0 or higher

• SDL2_ttf

• Unix-like environment (Linux, WSL, or macOS)

Building Alterm

Clone the repository and build the project using the provided Makefile.

$  git  clone  https://github.com/zoldyck13/alterm.git

$  cd  alterm

Project Structure

├── alterm/
│ ├── include/
│ │ ├── Alterm.hpp
│ │ ├── AnsFilter.hpp
│ │ ├── FontManagar.hpp
│ │ ├── forkpty.hpp
│ │ ├── HistoryManager.hpp
│ │ ├──SettingsManager.hpp
│ │
│ ├── src/
│ │ ├── Alterm.cpp
│ │ ├── AnsFilter.cpp
│ │ ├── FontManager.cpp
│ │ ├── forkpty.cpp
│ │ ├── HistoryManager.cpp
│ │ ├── main.cpp
│ │ ├── SettingsManager.cpp
│ │
│ │
│ │
│ ├── Makefile
│ ├── README.md
├ ├── LICENSE
├ ├──.alterm_history
├ ├── .alterm_settings
│ ├── assets/
│ │ ├── Fonts/
│ │ ├── Alterm.gif
│ │
│ │

  

$  make

This will build the source code and generate the executable ./alterm.

Running Alterm

After building the project, run the terminal with:

$  ./alterm

Usage

You can enter:

• ** Shell commands** like ls, cd, top, etc.

• Type settings to enter Settings Mode:

• set - change settings

• save - write settings to .alterm_settings

• exit - exit settings mode

Example

settings

set  font_size  16

save

exit

Settings Keys

Settings Keys

Key	Description
font_size	Font size (int)
font_family	Path to TTF font
font_color_r/g/b	Font color (R, G, B)
bg_color_r/g/b	Background color (R, G, B)
bg_opacity	Background transparency (0–255)
auto_scroll	Enable/disable auto scroll

Future Work

• Cursor navigation (<- / ->)

• In-line text editing

• Text selection and clipboard support

• Command auto-completion and Tab completion

• Mouse-based interaction

• Syntax highlighting

• ANSI escape sequences support

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What I Learned

• Deepen understanding of pseudo-terminal communication

• Learn real-time rendering with SDL2

• Create a customizable terminal-like interface from scratch

Licnese

This project is licensed under the MIT License - see the LICENSE file for details.