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Box Draw Characters

J draws boxes in the display of boxed data. The most portable way of drawing boxes is with the ascii characters +|- as shown in the following:

|2  |3  |4   |

It isn't pretty, but displays predictably in all environments,  works in plain text email, and is the most portable form for communicating between users. When these aren't important and you have a suitable font you can use special box draw chars to provide crisper displays.

Profile, depending on JFE configuration, sets special box draw characters when possible.

There are 3 sets of box draw characters: portable, OEM, and unicode. The boxes are just drawn with chars so in all cases the display only looks right only with a fixed pitch font.

J draws boxes with 11 characters:
upper left corner     T down        upper right corner
T right               cross         T left
lower left corner     T up          lower right corner
vertical              horizontal

The values for the 11 characters can be queried  with 9!:6 and set with 9!:7.

Box draw with +|- is set with:
   9!:7 '+++++++++|-'

Box draw with special OEM font chars is set with:
   9!:7 [ 218 194 191 195 197 180 192 193 217 179 196{a.

Box draw with Unicode font chars is set with:
   9!:7 [ (16+i.11){a.

J Engine input/output is in UTF-8 and the 9!:7 Unicode setting results in the Unicode values:
9484 9516 9488 9500 9532 9508 9492 9524 9496 9474 9472

Some unicode fixed pitch fonts don't have box draw characters of the same pitch and aren't useable.


The default darwin installation doesn't have a fixed pitch font with Unicode box draw characters of the correct width.

The DejaVu Sans Mono freely available from http://dejavu.sourceforge.net has proper box draw characters.

install procedure:
- download zip file
- extract DejaVuSansMono.ttf (fixed pitch regular)
- drag to /Users/user/Library/Fonts/ (or double click)
- start J
- select the font in Edit|Configure
- select Linedraw in Edit|Configure
- restart J and test

install for Jconsole:
- in Terminal menu, Window Settings, select Display
- uncheck "Wide glyphs for Japanese..."
- select DejaVu Sans Mono
- select "Use These Setting as Default"

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