thumb|right|320px|[[Midnight Commander using box-drawing characters in a terminal emulator]]
Box-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. These characters are characterized by being designed to be connected horizontally and/or vertically with adjacent characters, which requires proper alignment. Box-drawing characters therefore typically only work well with monospaced fonts.
In graphical user interfaces, these characters are much less useful as it is simpler to draw lines and rectangles directly with graphical APIs. However, they are still useful for command-line interfaces and plaintext comments within source code.
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.
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.
Unicode
Box Drawing
Unicode includes 128 such characters in the Box Drawing block.
Historical
Many microcomputers of the 1970s and 1980s had their own proprietary character sets, which also included box-drawing characters. Many of these were added to Unicode as Symbols for Legacy Computing.
Commodore
Commodore machines, such as the Commodore PET and the Commodore 64, included a set of text semigraphics with block elements and dithering patterns in the PETSCII character set.
640px|thumb|left|[[Commodore PET|PET 2001 keyboard layout, illustrating PETSCII graphics characters]]
Sinclair
frame|ZX81 semigraphics
The Sinclair ZX80, ZX81, and ZX Spectrum included a set of text semigraphics with quadrant-based block elements. The ZX80 and ZX81 also included a set of text semigraphics with dithering patterns.
BBC and Acorn
The BBC Micro could utilize the Teletext 7-bit character set, which had 128 box-drawing characters, whose code points were shared with the regular alphanumeric and punctuation characters. Control characters were used to switch between regular text and box drawing.
!
!0!!1!!2!!3!!4!!5!!6!!7!!8!!9!!A!!B!!C!!D!!E!!F
|-
!2
| NBSP
| 🬀
| 🬁
| 🬂
| 🬃
| 🬄
| 🬅
| 🬆
| 🬇
| 🬈
| 🬉
| 🬊
| 🬋
| 🬌
| 🬍
| 🬎
|-
!3
| 🬏
| 🬐
| 🬑
| 🬒
| 🬓
| ▌
| 🬔
| 🬕
| 🬖
| 🬗
| 🬘
| 🬙
| 🬚
| 🬛
| 🬜
| 🬝
|-
!6
| 🬞
| 🬟
| 🬠
| 🬡
| 🬢
| 🬣
| 🬤
| 🬥
| 🬦
| 🬧
| ▐
| 🬨
| 🬩
| 🬪
| 🬫
| 🬬
|-
!7
| 🬭
| 🬮
| 🬯
| 🬰
| 🬱
| 🬲
| 🬳
| 🬴
| 🬵
| 🬶
| 🬷
| 🬸
| 🬹
| 🬺
| 🬻
| █
|}
{| class="wikitable"
|+ Braille Sextant Mosaics Set
!
!0!!1!!2!!3!!4!!5!!6!!7!!8!!9!!A!!B!!C!!D!!E!!F
|-
!2
| NBSP
| 🬳
| 🬇
| 🬷
| 🬥
| 🬡
| 🬴
| 🬏
| 🬺
| 🬻
| 🬟
| 🬯
| 🬞
| 🬭
| 🬠
| 🬑
|-
!3
| 🬵
| 🬃
| 🬓
| 🬋
| 🬩
| 🬢
| 🬚
| 🬹
| 🬱
| 🬖
| 🬧
| 🬦
| 🬣
| █
| 🬘
| 🬨
|-
!4
| 🬁
| 🬀
| 🬄
| 🬂
| 🬊
| 🬈
| 🬆
| 🬎
| 🬌
| 🬅
| 🬍
| 🬐
| ▌
| 🬒
| 🬙
| 🬗
|-
!5
| 🬕
| 🬝
| 🬛
| 🬔
| 🬜
| 🬮
| 🬲
| 🬫
| 🬰
| 🬸
| 🬶
| 🬤
| 🬪
| 🬬
| 🬉
| ▐
|}
The BBC Master and later Acorn computers have the soft font by default defined with line drawing characters.
{| class="wikitable"
!
!0!!1!!2!!3!!4!!5!!6!!7!!8!!9!!A!!B!!C!!D!!E!!F
|-
!A
| ||╷||╶||┌||╴||┐||─||┬||╵||│||└||├||┘||┤||┴||┼
|-
!B
|╭||╮||╰||╯|| || || || || || || || || || || ||
|}
Amstrad
The Amstrad CPC character set also has soft characters defined by default as block and line drawing characters.
{| class="wikitable"
!
!0!!1!!2!!3!!4!!5!!6!!7!!8!!9!!A!!B!!C!!D!!E!!F
|-
!8
| ||▘||▝||▀||▖||▍||▞||▛||▗||▚||▐||▜||▃||▙||▟||▉
|-
!9
| ||╵||╶||└||╷||│||┌||├||╴||┘||─||┴||┐||┤||┬||┼
|}
The CP/M Plus character set used on various Amstrad computers of the CPC, PCW and Spectrum families included a rich set of line-drawing characters as well:
</references>