The growing accessibility and pervasiveness of digital devices such as computers, PDAs, cell phones, and
digital projectors have given rise to many "on-screen only" applications for type. Because these letterforms are created through
the combination of pixels, the quality and legibility of the type these devices can display is limited by the screen resolution
(measured in pixels) each is capable of.
The illusion of smoothness of on-screen type is created through "anti-aliasing." Anti-aliasing works by filling in the jagged
shapes around curves in letterforms with lighter pixels, tricking the eye into seeing a smoother outline. However, this technique causes
elements of letterforms, such as the thick and thin strokes of serif typefaces, to lose legibility, especially at lower screen resolutions.
This has led to the design of typefaces — so-called "pixel fonts" — specifically for digital display that are legible at smaller sizes because
they do not require smoothing.
