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Staircase (aliasing) effect

Short answer

Staircase effect, or jaggies, is the stair-step appearance of slanted lines and curves on raster displays because discrete pixels approximate continuous shapes. It is a form of aliasing, most visible at low resolution, and reduced by higher resolution or anti-aliasing techniques.

What is a staircase effect?

The staircase effect (jaggies) is the stair-step appearance of lines, curves and edges drawn on a raster display. Because the screen consists of discrete pixels, a slanted line or curve can only be approximated by pixels at integer positions, so it looks like steps instead of a smooth line.

Ideal line:        Displayed:
       /                  ##
      /                 ##
     /                ##

It is a form of aliasing. It is most visible on low-resolution screens and for lines that are nearly horizontal or vertical. It is reduced by increasing the resolution or by anti-aliasing techniques such as supersampling, area sampling and pixel phasing.

✓ Answer checked by Claude Opus 5.5 (high effort)

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