emWin

emWin is a commercial embedded graphical user interface (GUI) library developed by SEGGER Microcontroller. It provides a complete GUI toolkit for resource-constrained devices with color displays, touch input and event-driven operation. The library is designed to be portable across different microcontrollers, CPUs and real-time operating systems, and it emphasizes small footprint and fast rendering.

Features include a comprehensive widget set (buttons, sliders, check boxes, list boxes, menus, edit controls), bitmap and font handling, image formats, color management, windowing, and support for anti-aliased rendering and touch input. The API follows a Windows-like model and uses a hierarchical windowing system.

Platform and licensing: emWin is proprietary software licensed by SEGGER. It is distributed in source code form and compiled into applications; licensing terms vary by end customer and device count. It is commonly used in embedded toolchains, including STMicroelectronics' STM32 software packages where it is branded as STemWin.

Development workflow: Works with C/C++ toolchains on ARM Cortex-M and other targets, and integrates with common IDEs and RTOS such as FreeRTOS or RTX; supports resource management (colors, fonts, bitmaps, palettes) and debugging capabilities.

Impact and usage: EmWin has been widely adopted in automotive, medical devices, consumer electronics, and industrial equipment where modern graphical interfaces are required on embedded hardware.