What are Jaggies?
Jaggies are visible stair-step artifacts along diagonal or curved edges in raster imagery. They commonly result from insufficient sampling resolution or missing or inadequate antialiasing.
How Jaggies work
These edge steps are a spatial-sampling artifact: a continuous boundary is represented on a finite pixel grid without enough filtering or sample density. They can enter during rasterization, geometric transforms, compositing, or final downsampling, even when the source asset was smooth. Antialiasing estimates partial pixel coverage, while reconstruction filters suppress frequencies the output grid cannot represent. Quality control should inspect the actual delivery scale because zoom level and display scaling change their visibility.
Key facts
- Jaggies follow edge geometry and pixel spacing, whereas JPEG blocking follows transform-block boundaries; treating both as compression damage leads to the wrong remedy.
- Rotating or rescaling an already rasterized edge can alias it again, so antialiased source pixels do not remove the need for a suitable output resampling filter.
- Supersampling reduces edge error by rendering at a denser grid and filtering down, but its memory and shading cost grows with the number of intermediate samples.
When Jaggies matter
Rendering at higher resolution or applying suitable antialiasing and resampling filters can reduce jaggies. Excessive smoothing trades sharper edges and fine detail for a less visibly stepped contour.