sidebearing

Sidebearing refers to the space on either side of a typeface character, specifically the amount of white space to the left and right of the glyph. This spacing is crucial for the legibility and aesthetic appearance of text. Proper sidebearing ensures that characters do not appear too close together or too far apart when placed next to each other, creating a harmonious flow of text.

The sidebearings of a font are determined by the type designer during the font creation process. They are not uniform for all characters. For example, a narrow character like "i" will typically have smaller sidebearings than a wide character like "W". Similarly, certain character combinations, known as kerning pairs, may require specific adjustments to their sidebearings to avoid visual gaps or overlaps.

In digital typography, sidebearings are measured in units and are an integral part of the font's metadata. They influence how the characters are spaced out by default, forming the foundation for more advanced spacing adjustments like kerning. When a font is rendered, the sidebearings define the horizontal space that each character occupies before the next character begins. Consistent and well-considered sidebearings are essential for creating readable and visually pleasing typography across various applications, from body text to headlines.