-- mode: org; coding:utf-8; --

+TITLE: Uniline

+OPTIONS: ^:{} authors:Thierry Banel, toc:nil

• Pure UNICODΕ text diagrams Draw diagrams like those:

Document a command:

[[file:images/document-command.png]]

+begin_example

pdfjam source.pdf 3-5,9 ▲ ▲ ▲ ▲ command╶╯ │ │ │ input file╶──╯ │ │ select pages 3,4,5╶───╯ │ and page 9╶──────────────╯

+end_example

Connect boxes with arrows:

[[file:images/boxes-arrows.png]]

+begin_example

        ╭───────────────────────╮

╷123╭────▶┤ hundred and something │ ╰───╯ ╰───────────────────────╯ ╭────▶──╮A╷ ╭───╮ ┏━━━┓ ╔═══╗ │ ╰─╯ 0╶─→┤ 1 ┝━━━▶┫ 2 ┣═══▷╣ 3 ╟──●────▶──╮B╷ ╰───╯ ┗━┯━┛ ╚═╤═╝ │ ╰─╯ ╰────←───╯ ╰────▶──╮C╷ ╰─╯ ╔══════════╗ ║ 1 ║ ▐▀▀▀▀▀▀▀▀▜ ║ ╭─────╫───╮ ◁──▷ ▐ 3 ▐ ╚════╪═════╝ 2 │ ▐▄▄▄▄▄▄▄▄▟ ╰─────────╯

+end_example

Explain decisions trees:

[[file:images/decision-tree.png]]

+begin_example

┏━━━━━━━━━━━━┓ ┃which color?┃ ┗━┯━━━━━━━━━━┛ │ ╭──────╮ │ ╭──┤yellow├─▷╮good─choice╭□ ▽ │ ╰──────╯ ╰═══════════╯ ╰──● ╭───╮ ┏━━━━━┓ ├──┤red├───▷┨dark?┠──╮ │ ╰───╯ ┗━━━━━┛ │ │ ╭───◁──────────────╯ │ │ ╭───╮ │ ╰─●─┤yes├▷╮regular─red╭─□ │ │ ╰───╯ ╰═══════════╯ │ │ ╭──╮ │ ╰─┤no├─▷╮pink╭────────□ │ ╰──╯ ╰════╯ │ ╭────╮ ├──┤blue├───▷╮next week╭──□ │ ╰────╯ ╰═════════╯ │ ╭─────╮ ╰──┤white├──▷╮available╭──□ ╰─────╯ ╰═════════╯

+end_example

Draw lines or blocks:

[[file:images/lines-blocks.png]]

+begin_example

                          ╭─╮←─╮
                     ╭╮   │ │  ╰──╴max 235
                   ╭╮││  ╭╯ │
                   │╰╯│╭─╯  │
  ╭╮               │  ││    │

╭─╮││╭╮ ╭──╮╭╮ │ ╰╯ ╰╮ ╭╯ ╰╯╰╯│ ╭╯ ╰╯╰─╮ │ │ ╭╮ ◁─╯ ╰──╯ ╰──╯ ╰─╯╰────▷ ◀════════════════════════════════════════▶ ╭────────╮ ▲ │all time│ ┃ ▄ ▗▟█ ←─┤highest │ Qdx █▌ ████ ╰────────╯ ┃ ▗▄█▌ █████▙ ┃ ▟███████▄█████████▄▄▄ ▗▄ ┃▐▄▄████████████████████████████▄▄▖ ╺━━━━━━━━━━╸time╺━━━━━━━━━━━━━━━━▶

+end_example

Explain Lisp lists:

[[file:images/lisp-lists.png]]

+begin_example

'(a b c) ┏━━━┳━━━┓ ┏━━━┳━━━┓ ┏━━━┳━━━┓ ●━━━▶┫ ● ┃ ●─╂──▷┨ ● ┃ ●─╂──▷┨ ● ┃nil┃ ┗━┿━┻━━━┛ ┗━┿━┻━━━┛ ┗━┿━┻━━━┛ │ ╰──────────╮╰╮ │ ╭─────┬───────────╮ │ │ ╰─▷┤"a\0"│properties │ │ │ ├─────┼───────────┤ │ │ │"b\0"│properties ├◁╯ │ ├─────┼───────────┤ │ │"c\0"│properties ├◁──╯ ├─────┼───────────┤ │... │... │ ╵ ╵ ╵

+end_example

Draw sketched objects:

[[file:images/sketched-objects.png]]

+begin_example

◀─(-)────────(+)──▶ ~╭──────╮~ ▗──────────────╮ │ ╭╮ │~~ ▐ ╰╮ ~│ ╵ ╵ │~ ╭□▐ 1.5 volts ╭╯□╮ ╰─╖ ╓─╯ │ ▝▀▀▀▀▀▀▀▀▀▀▀▀▀▀▘ │ ╠━━╣ │ ╰──────╯ │ ╰─────────────────────────────╯

+end_example

Those diagrams are pure text. There is nothing graphic. They are achieved using UNICODE characters. Most often, the text file will be encoded as UTF-8.

Creating such diagrams by hand is painfully slow. Use Uniline to draw lines while you move the cursor with keyboard arrows.

Beware!

If you see those diagrams miss-aligned, most likely the font used to display them does not support UNICODE block characters. See bellow the paragraph "Which fonts?".

• Minor mode Uniline is a minor mode. Activate it temporarily:

  =M-x uniline-mode=

Exit it with:

=C-c C-c=

The current major mode is still active underneath =uniline-mode=.

While in =uniline-mode=, overwritting is active, as well as long lines truncation. Also, a hollow cursor is provided. Those settings are reset to their previous state when exiting =uniline-mode=.

• Drawing lines Use keybord arrows to draw lines.

By default, drawing lines only happens over empty space or over other lines. If there is already text, it will not be erased. However, by hiting the control-key while moving, lines overwrite whatever there is.

The buffer is "infinite" in bottom and right directions. Which means that when the cursor ends up outside the buffer, white space characters are automatically added.

The usual numeric prefix is available. For instance, to draw a line 12 characters wide downward, type: =M-12 =

• Brush style Set the current brush with:

• =-= single thin line =╭─┬─╮=

• =+= single thick line =┏━┳━┓=

• = = = double line =╔═╦═╗=

• =#= quarter block =▙▄▟▀=

• == eraser

• == move without drawing anything

• The == key The == key is a prefix for other keys:

• for drawing arrows, squares, crosses, o-shapes glyphs,

• for handling rectangles,

• for inserting =# = - += which otherwise change the brush style,

• for trying a choice of monospaced fonts.

Why ==? Because:

• Uniline tries to leave their original meaning to as much keys as possible,
• the standard meaning of == is to toggle the overwrite mode; but Uniline is already in overwrite mode, and de-activating overwrite would break Uniline.

So preempting == does not sacrifices anything.

• Arrows glyphs =▷ ▶ →= At any time, an arrow may be drawn. The arrow points in the direction that the line drawing follows.

Uniline supports 3 arrows: =▷ ▶ →=

Actually, there are tons of arrows of all styles in the UNICODE standard. Unfortunately, the support by fonts is weak. So Uniline restrains itself to those three safe arrows.

To insert an arrow, type: =a= or =aa= or =aaa=. (=a= cycles through the 3 styles, =A= cycles backward).

=3a= is equivalent to =aaa=, which is also equivalent to =A=. Those 3 shortcuts insert an arrow of this style: =→↑←↓=. The actual direction where the arrow points follows the last movement of the cursor.

To change the direction of the arrow, use shift-arrow, for example: =S-= will change it from =→= to =↑=.

• Intersection glyphs =■ ◆ ●= There are a few other UNICODE characters which are monospace and symetric in the 4 directions. They are great at line intersections:

To insert a square =□ ■ ◇ ◆ ◊= type: =sss...= (=s= cycles, =S= cycles backward).

To insert a circular shape =· ● Ø ø= type: =ooo...= (=o= cycles, =O= cycles backward).

To insert a cross shape =÷ × ± ¤= type: =xxx...= (=x= cycles, =X= cycles backward).

To insert a usual ASCII letter or symbol, just type it.

As the keys =- + = #= are preempted by Uniline mode, to type them, prefix them with ==. Example: =-= inserts a =-= and =+= inserts a =+=.

+begin_example

╷ ╷ ╷ ╷ ╶◆─◇─■─□╴ │ │ │ │ ╶─▷─▶─→─────╮ ╶·─●─Ø─ø╴ ╭─◆─◇─■─□──╯ │ │ │ │ ╰─·─●─Ø─ø──╮ ╶¤─±─×─÷╴ ╭─¤─±─×─÷──╯ │ │ │ │ ╰─a─b─c─d──╮ ╶a─b─c─d╴ ╭─#─-─+─$──╯ │ │ │ │ │ ╷ ╷ ╭╮ ╭╮ ╷ ╭╮ ╷ ╭╮ ╶#─-─+─$╴ ╰──0──1──2┴─3┴─4──5┴─6──7┴╴ │ │ │ │

+end_example

• Drawing rectangles To draw a rectangle in one shot, select a rectangular region with =C-SPC= or =C-x SPC= and move the cursor.

If needed, change the brush with any of =-= =+= === =#= ==

then hit

• =r= to draw a rectangle inside the selection
• =R= to draw a rectangle ouside the selection

+begin_example

╭───────╮ r: inside╮╭───────╮ │ one │ ▗▄▄▄▄▄▄▖╭┤│▛▀▀▀▀▀▜│ │ ┏━━━━┿━━━━━━┓ ▐╭────╮▌│╰┼▌ ▐│ ╰──╂────╯ two ┃ ▐│ │▌│ │▙▄▄▄▄▄▟│ ┃ ╔═══════╋═╗ ▐│ ├▌╯ ╰─────┬─╯ ┗━━━╋━━━━━━━┛ ║ ▐╰────╯▌────────┴───╮ ║ three ║ ▝▀▀▀▀▀▀▘ R: outside╯ ╚═════════╝

                      ╭─────────╮

my text I │my text I│ want to ╶─R─▷ │want to │ box │box │ ╰─────────╯

+end_example

The usual =C-_= key may be hit to undo, even with the region still active visually.

• Moving rectangles Select a region, then press ==. The selection becomes rectangular if it was not.

Use arrow keys to move the rectangle around. A numeric prefix may be used to move the rectangle that many characters. Be sure to specify the numeric prefix with just digits, without the =Alt= key. Typing =15= moves the rectangle 15 characters to the left. =M-15= does not work.

Press =q=, =RET=, or =C-g= to stop moving the rectangle.

The =C-_= key may also be used to undo the previous movements, even though the selection is still active.

+begin_example

             ▲
             │
            <up>
       ╭─────┴──────╮
       │this is     │
       │my rectangle│

◀───┤I want to ├──▶ │move │ │ % + │ ╰─────┬──────╯