antialiassing

Antialiasing is a collection of techniques in computer graphics designed to reduce aliasing, the jagged appearance of diagonal or curved edges in raster images. In rasterization, edges are rendered on a grid of square samples, which can produce stair-step artifacts known as jaggies. Antialiasing smooths edges by blending colors across neighboring samples or by increasing the effective sampling rate, thereby producing the impression of a higher-resolution edge without fully geometric detail.

Antialiasing methods are categorized by when and how they sample. Supersampling anti-aliasing renders the scene at a higher resolution and then downscales to the target resolution, providing high quality at the cost of performance. Multisample anti-aliasing uses multiple samples per pixel focused on edges, with shading performed per pixel to reduce overhead. Post-process anti-aliasing, such as FXAA and SMAA, analyzes the final image and applies filters to smooth edges in screen space. Temporal anti-aliasing, including TXAA and related techniques, accumulates information across frames to lessen flicker and shimmering, sometimes at the cost of slight blur or ghosting along motion. Each method balances quality, speed, and artifact tendencies.

Subpixel rendering, exploiting the layout of LCD subpixels, can enhance the apparent sharpness of small text and fine graphics but is distinct from standard geometry anti-aliasing. Antialiasing is widely used in video games, 3D rendering, and digital typography to improve perceived image quality without requiring more geometry.