Spacing and Non-spacing Characters
Most graphic characters are spacing characters, which means that each instance of a spacing character has to occupy some area in a graphic representation. For a teletype or a typewriter this implies moving of the carriage after typing of a character. In the context of text mode display, each spacing character occupy one rectangular character box of equal sizes. Or maybe two adjacent ones, for non-alphabetic characters of East Asian languages. If a text is rendered using proportional fonts, widths of character boxes are not equal, but are positive.
There exists also non-spacing graphic characters. Most of non-spacing characters are modifiers, also called combining characters in Unicode, such as diacritical marks. Although non-spacing graphic characters are uncommon in traditional code pages, there are many such in Unicode. A combining character has its distinct glyph, but it applies to a character box of another character, a spacing one. In some historical systems such as line printers this was implemented as overstrike.
Note that not all modifiers are non-spacing – there exists Spacing Modifier Letters Unicode block.
Read more about this topic: Graphic Character
Famous quotes containing the word characters:
“Of all the characters I have known, perhaps Walden wears best, and best preserves its purity. Many men have been likened to it, but few deserve that honor. Though the woodchoppers have laid bare first this shore and then that, and the Irish have built their sties by it, and the railroad has infringed on its border, and the ice-men have skimmed it once, it is itself unchanged, the same water which my youthful eyes fell on; all the change is in me.”
—Henry David Thoreau (1817–1862)