Hardware Abstraction API: OpenGL, Vulkan, DirectX
Graphics API implementations: 2D: DRM, GDI, Graphics Card Drivers (DirectX/OpenGL/Vulkan), | 3D: Graphics Card Drivers (DirectX/OpenGL/Vulkan), Mesa3D
- Wayland and Direct2D don't directly access 2D drivers.
3D GUI Libraries:
- ImGui (3D Apps)
- OGRE
- VTK
Low Level GUI Libraries
- SFML (Multimedia Library; Low userbase; uses modern C++ and OOP)
- SDL (Low Level / Pixel manipulation)
  - If using a graphics API (OpenGL/Vulkan), it works better with OpenGL
  - No networking built-in; can use 3rd party libraries for video games
- GLFW (Only window and input handling)
- GLUT (Old and buggy; There is FreeGLUT, still, use SFML/SDL/GLFW instead)

note

Probaly should organize widget frameworks as cross-platform>language and platform specific>platform>language

note

Framework and Toolkit are loosely defined words. I guess framework means something larger than a toolkit.

Widget Frameworks:
- C++: Qt
- Python: PyQt5, wxWidgets, Tkinter, wxPython, Pyforms, Kivy
- Other: GTK4
Widget Toolkits:
- Cross Platform: GTK, Qt, Tcl/Tk, ImGui, FLTK, GNUSTEP, XUL, IUP, Nuklear, Xamarin.Forms
- Windows only:
  - Common Language Infrastructure (CLI; .NET): WinForms, XAML (WPF, WinUI, Silverlight), XNA
  - C++: MFC, Active Template Library, Windows Template Library, Object Windows Library
  - Pascal: Visual Component Library
  - Low Level: Win32, UWP
- Linux/X11(/Wayland) only:
  - XForms, Motif, EFL
  - Low Level: Xlib, XCB (modern alternative to Xlib), GDK (GTK backend)
- Apple only: Cocoa, Cocoa Touch, Xamarin.Mac, Xamarin.iOS
- Android: Xamarin.Android, Qt for Android
- Java: AWT, Swing, JavaFX
Windows
- GDI (Original graphics interface; closely tied to Win32)
- GDI+ (Introduced as a successor to GDI in XP)
- Direct2D (Modern replacement for GDI based on Direct3D introduced in Windows 7)
  - Supports fully hardware-accelerated alpha-blending, hence anti-aliasing, and also vector graphics
- Direct3D (3D API)
- DirectWrite (Text layout and rasterization engine; Rasterized text can be displayed with GDI/Direct2D)
- DXGI (Low level infrastructure for Direct3D)
- Window Compositing: Desktop Window Manager (DWM) was introduced in Vista. Before that, apps could draw directly to screen, causing trails when unresponsive.
Linux
- Uses X11 or Wayland
- Kernel Driver (DRI / Vendor) + Userspace Library (Mesa 3D / Vendor)
- DirectX Implementations: Gallium Nine, DXVK, VKD3D
Apple
- Graphics API: Mantle
- Graphics Library: Carbon
- Graphics Framework: Cocoa

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