Graphic character

Source: Wikipedia, the free encyclopedia.

In

ISO 8859 and Unicode, a graphic character, also known as printing character (or printable character), is any character intended to be written, printed, or otherwise displayed in a form that can be read by humans. In other words, it is any encoded character that is associated with one or more glyphs
.

ISO/IEC 646

In ISO 646, graphic characters are contained in rows 2 through 7 of the

space character SP at row 2 column 0 and the delete character
 DEL (also called the rubout character) at row 7 column 15, require special mention.

The space is considered to be both a graphic character and a control character in ISO 646. It can have a visible form, and also a control function (moving the print head).[1]

The delete character is strictly a control character, not a graphic character. This is true not only in ISO 646, but also in all related[clarification needed] standards including Unicode. However, many other character sets deviate from ISO 646, and as a result a graphic character might[a] occupy the position originally reserved for the delete character.[b]

Unicode

In Unicode, Graphic characters are those with

General Category Letter, Mark, Number, Punctuation, Symbol or Zs=space. Other code points (General categories Control, Zl=line separator, Zp=paragraph separator) are Format, Control, Private Use, Surrogate, Noncharacter or Reserved (unassigned).[2]

Spacing and non-spacing characters

Most graphic characters are spacing characters, which means that each instance of a spacing character has to occupy some

positive
.

There exist 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.

See also

Notes

  1. ^ as is the case in code page 437 and related standards
  2. POKE
    will output the graphical character.

References

  1. ISBN 978-1-4831-4484-9
    .
  2. ^ https://www.unicode.org/versions/Unicode5.2.0/ch02.pdf#G25564 Chapter 2, table 2.3
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