On many Unix systems and early dial-up bulletin board systems the only common standard for box-drawing characters was the VT100 alternate character set (see also: DEC Special Graphics). Some OEM DOS computers supported other character sets, for example the Hewlett-Packard HP 110 / HP Portable and HP 110 Plus / HP Portable Plus, where in a modified version of the character set box-drawing characters were added in reserved areas of their normal HP Roman-8 character set. Note: The non-double characters are the thin (light) characters (U+2500, U+2502), not the bold (heavy) characters (U+2501, U+2503). Their number is further limited to 28 on those code pages that replace the 18 characters that combine single and double lines, the left and right half blocks, as well as integral halves with other, usually alphabetic, characters (such as code page 850): The integral halves are also box drawing as they are used alongside 0xB3: This subset of the Unicode box-drawing characters is thus included in WGL4 and is far more popular and likely to be rendered correctly: The hardware code page of the original IBM PC supplied the following box-drawing characters, in what DOS now calls code page 437. Various different platforms defined their own unique set of box-drawing characters. ^ Grey areas indicate non-assigned code points Few fonts support these characters, but the table of symbols is provided here: In version 13.0, Unicode was extended with another block containing many graphics characters, Symbols for Legacy Computing, which includes a few box-drawing characters and other symbols used by obsolete operating systems (mostly from the 1980s). The Block Elements Unicode block includes shading characters. The image below is provided as a quick reference for these symbols on systems that are unable to display them directly: Official Unicode Consortium code chart (PDF) In many Unicode fonts only the subset that is also available in the IBM PC character set (see below) will exist, due to it being defined as part of the WGL4 character set. Unicode includes 128 such characters in the Box Drawing block. Other types of box-drawing characters are block elements, shade characters, and terminal graphic characters these can be used for filling regions of the screen and portraying drop shadows. Some recent embedded systems also use proprietary character sets, usually extensions to ISO 8859 character sets, which include box-drawing characters or other special symbols. However, they are still useful for command-line interfaces and plaintext comments within source code. In graphical user interfaces, these characters are much less useful as it is more simple and appropriate to draw lines and rectangles directly with graphical APIs. Box-drawing characters therefore typically only work well with monospaced fonts. These characters are characterized by being designed to be connected horizontally and/or vertically with adjacent characters, which requires proper alignment. Midnight Commander using box-drawing characters in a terminal emulatorīox-drawing characters, also known as line-drawing characters, are a form of semigraphics widely used in text user interfaces to draw various geometric frames and boxes. Without proper rendering support, you may see question marks, boxes, or other symbols. This article contains special characters.
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