minigui

minigui is an experimental library for creating graphical user interfaces from Gleam (Erlang target) using a native external C port.

Status / scope

• Windows: Win32 backend (window + label + textbox + button).
• Linux: GTK3 backend (window + label + textbox + button).
• macOS: for now, headless mode only (simulated).

Note: on Linux the minigui binary links against GTK3, so the system must have GTK3 available at runtime (common on desktops; on minimal servers you may need to install packages).

The goal is to keep a small, stable API in Gleam, while enabling native per-platform backends.

Releases / publishing

See the checklist: RELEASING.md

Installation (Gleam Packages)

gleam add minigui

"Build-dependency-free" (precompiled binary)

To avoid requiring your users to install a C compiler or headers (libx11-dev, etc.), minigui is designed to use a precompiled executable as a bridge (a port) and download it automatically into priv/ on first use.

By default it builds the URL like this:

https://github.com/Aztekode/minigui/releases/download/v<version>/<asset>

Where <version> comes from the package vsn (e.g. 0.1.0) and <asset> depends on the OS/architecture, for example:

• minigui.exe (Windows x64)
• minigui (Linux x64)

You can override the download base with:

MINIGUI_RELEASE_BASE_URL="https://github.com/Aztekode/minigui/releases/download/v0.1.2"

If you prefer an exact link like .../minigui.exe, you can set the full URL:

MINIGUI_PORT_URL="https://github.com/Aztekode/minigui/releases/download/v0.1.2/minigui.exe"

Security/cache options:

• By default, miniguirequiresminigui(.exe).sha256 to exist and validates the SHA256.
• MINIGUI_REQUIRE_SHA=0: disables validation (not recommended).
• The binary is cached per user (Linux: ~/.cache/minigui/<version>/, Windows: %LOCALAPPDATA%\\minigui\\<version>\\).

Runtime requirement: a "full" Erlang/OTP installation that includes the standard inets + ssl applications (they usually ship with OTP; on some Linux distros they may be split into separate packages).

Protocolo (v1)

The port is opened with open_port(..., [{packet, 2}, binary, ...]).

• Handshake:

  • 0x00HELLO + u16 version
  • 0xF0HELLO_ACK + u16 version + u32 capabilities

• Commands:

  • 0x10CREATE_WINDOW + u32 request_id + UTF-8 title
  • 0x11SET_LABEL + u32 request_id + UTF-8 text
  • 0x12SET_TEXT + u32 request_id + UTF-8 text
  • 0x13ADD_BUTTON + u32 request_id + u8 id + UTF-8 label
  • 0x14RUN + u32 request_id
  • 0x15QUIT + u32 request_id

• Responses:

  • 0x70OK + u32 request_id
  • 0x71ERR + u32 request_id + UTF-8 message

• Events:

  • 0x81BUTTON_CLICKED + u8 id
  • 0x82CLOSED
  • 0x83LOG + UTF-8 text
  • 0x84TEXT_CHANGED + UTF-8 text
  • 0x85KEY_DOWN + u32 keycode
  • 0x86ERROR + UTF-8 text

Build (Linux)

Requirements: gcc, make, pkg-config, libgtk-3-dev, Erlang/OTP, gleam.

Tested with Gleam v1.17.0.

make port
gleam build
make demo

If you're in an environment without an X server (CI/headless), force simulated mode:

MINIGUI_HEADLESS=1 make demo

Build (Windows)

1. Compile the port:

make port

1. Run the demo:

gleam build
gleam run -m demo

Note: the Win32 code is inside #ifdef _WIN32.