Editing Subpixel rendering (section)

== Characteristics ==

A single pixel on a color display is made of several subpixels, typically three arranged left-to-right as red, green, and blue (RGB). The components are easily visible when viewed with a small magnifying glass, such as a [[loupe]]. These pixel components appear as a single color to the human eye because of blurring by optics and spatial integration by nerve cells in the eye. However, the eye is much more sensitive to the location.{{clarify|date=March 2024}} Therefore, turning on the G and B of one pixel and the R of the next pixel to the right will produce a white dot, but it will appear to be 1/3 of a pixel to the right of the white dot that would be seen from the RGB of only the first pixel. Subpixel rendering takes advantage of this to provide three times the horizontal resolution of the rendered image, though it has to blur this image to produce the correct color by ensuring the same amount of red, green, and blue are turned on as when no subpixel rendering is being done.

Subpixel rendering does not necessitate the use of [[Spatial_anti-aliasing|antialiasing]], and gives a smoother result regardless of whether antialiasing is used or not <ref>{{Cite web|url=https://freddie.witherden.org/pages/font-rasterisation/|title=A Treatise on Font Rasterisation With an Emphasis on Free Software|date=2010-09-15|access-date=2023-11-11}}</ref> since it artificially increases the resolution. However, it introduces color aliasing since subpixels are colored. Subsequent filtering applied to remove the color artifacts is a form of antialiasing, although its purpose is not smoothing jagged shapes as in conventional antialiasing.

Subpixel rendering requires the software to know the layout of the subpixels. The most common reason it is wrong is monitors that can be rotated 90 (or 180) degrees, though monitors are manufactured with other arrangements of the subpixels, such as BGR or in triangles, or with 4 colors like RGBW squares. On any such display the result of incorrect subpixel rendering will be worse than if no subpixel rendering was done at all (it will not produce color artifacts, but it will produce noisy edges).