Font file

A computer font (or font) is implemented as a digital data file containing a set of graphically related glyphs, characters, or symbols such as dingbats. Although the term font first referred to a set of movable metal type pieces in one style and size, since the 1990s it is generally used to refer to a set of digital shapes in a single style, scalable to different sizes. A font family or typeface refers to the collection of related fonts across styles and sizes.

There are three basic kinds of computer font file data formats:

Bitmap fonts are faster and easier to use in computer code, but non-scalable, requiring a separate font for each size. Outline and stroke fonts can be resized using a single font and substituting different measurements for components of each glyph, but are somewhat more complicated to render on screen than bitmap fonts, as they require additional computer code to render the outline to a bitmap for display on screen or in print. Although all types are still in use, most fonts seen and used on computers are outline fonts.

Fonts are designed and created using font editors. Fonts specifically designed for the computer screen and not printing are known as screen fonts.

Fonts can be monospaced (i.e., every character is plotted a constant distance from the previous character that it is next to, while drawing) or proportional (each character has its own width). However, the particular font-handling application can affect the spacing, particularly when doing justification.

A bitmap font is one that stores each glyph as an array of pixels (that is, a bitmap). It is less commonly known as a raster font. Bitmap fonts are simply collections of raster images of glyphs. For each variant of the font, there is a complete set of glyph images, with each set containing an image for each character. For example, if a font has three sizes, and any combination of bold and italic, then there must be 12 complete sets of images.

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Wikipedia