jaggies

Jaggies is a common term for the stair-step appearance of straight lines, diagonals, or curved edges in rasterized digital images. This aliasing artifact occurs when a continuous edge is sampled by a discrete grid, causing the edge to be represented by a sequence of horizontal or vertical steps rather than a smooth line. Jaggies are especially noticeable on low-resolution displays or in small text and simple geometric shapes.

The roots of jaggies lie in the mismatch between an edge’s true geometry and the sampling lattice used to represent it. Insufficient sampling density, limited polygonal detail, and texture or shading sampling can all produce visible stair-stepping. In font rendering, rasterization of curves and thin strokes often reveals jaggies, while in real-time graphics, coarse geometry and texture filtering contribute to the effect.

Mitigation strategies focus on reducing the visibility of jaggies rather than eliminating the underlying sampling limits. Anti-aliasing techniques blur or blend edge pixels to achieve smoother transitions. Approaches include supersampling (rendering at higher resolution and downsampling), multisample anti-aliasing (MSAA), and post-processing methods such as FXAA or SMAA. Increasing overall resolution, improving geometric detail, and using subpixel rendering for LCD displays can also lessen jaggies, particularly for text and fine lines. Vector rendering can render edges without jaggies, but is not always practical for all content.

Jaggies reflect the fundamental limits of digital sampling and are influenced by gamma encoding and perceptual factors. They remain a key consideration in display design, font rendering, and real-time graphics. See also aliasing, anti-aliasing, subpixel rendering, supersampling, MSAA, and rasterization.