A bitmap font is a computer font that uses a unit called a picture element called a pixel to build symbols called glyphs that make up a total bitmap font. This type of font is used when a compact, fast-loading font is essential. A bitmap font is sometimes called a raster font. A classic standard as far as fonts go, bitmap is one of the older types of fonts. It was used in dot matrix computers, and is still a relevant font in many software programs today.
There are several types of font that fall under the bitmap font category. The most common include server normal format (SNF), portable compiled format (PCF), glyph bitmap distribution format (BDF). Generally, different formats for bitmap fonts are used in different software suites, like the BDF bitmap font format used in software produced by Adobe®. Bitmap fonts are used when fonts need to load quickly, but they are not flexible and resizing the image causes it to degrade in quality.
Symbols in a font are called glyphs. Glyph refers to an individual written character that contributes to the meaning of an overall written piece. A font designer uses a font editor to design fonts and generally designs each glyph individually. Types of fonts include the bitmap font, the stroke font, and the outline font.
Though bitmap fonts are better for quick loading than other font types, bitmap font glyphs do not resize smoothly, making the font less convenient for fonts that need to be resized. With a bitmap font, a font designer has to create different fonts for a computer to render different font sizes while maintaining quality in the images of the characters. Bitmap fonts were most useful on older computer systems that lacked the memory and processing power to handle higher-demand fonts.
Glyphs can be many different types of symbols. A letter is a glyph, but not all glyphs are letters because glyph is a wider term that refers to characters and symbols that convey meaning in any written language. In some languages, a difference as small as the dot on a lower case i can be a glyph because it conveys the difference between different types of lower case i characters in that language. However, in English, the dot on a lower case i is generally not considered to be a glyph because there is no other i with which to confuse the character. In effect, the dot on the lower case i does not make any distinct change to the message, so it is not a glyph.