Rendering Reference / Reference Surface

§R1 Box-Drawing Characters

§R1.1 Single-Line (Light)

Used for: Level 1 panels, Level 2 menus, inactive windows (Standard §6.1, §6.2).

GlyphNameUnicodeDescription
─BOX DRAWINGS LIGHT HORIZONTALU+2500Horizontal line
│BOX DRAWINGS LIGHT VERTICALU+2502Vertical line
┌BOX DRAWINGS LIGHT DOWN AND RIGHTU+250CTop-left corner
┐BOX DRAWINGS LIGHT DOWN AND LEFTU+2510Top-right corner
└BOX DRAWINGS LIGHT UP AND RIGHTU+2514Bottom-left corner
┘BOX DRAWINGS LIGHT UP AND LEFTU+2518Bottom-right corner
├BOX DRAWINGS LIGHT VERTICAL AND RIGHTU+251CLeft T-junction
┤BOX DRAWINGS LIGHT VERTICAL AND LEFTU+2524Right T-junction
┬BOX DRAWINGS LIGHT DOWN AND HORIZONTALU+252CTop T-junction
┴BOX DRAWINGS LIGHT UP AND HORIZONTALU+2534Bottom T-junction
┼BOX DRAWINGS LIGHT VERTICAL AND HORIZONTALU+253CCross junction

§R1.2 Heavy (Thick)

Used for: optional emphasis borders, header separators.

GlyphNameUnicode
━BOX DRAWINGS HEAVY HORIZONTALU+2501
┃BOX DRAWINGS HEAVY VERTICALU+2503
┏BOX DRAWINGS HEAVY DOWN AND RIGHTU+250F
┓BOX DRAWINGS HEAVY DOWN AND LEFTU+2513
┗BOX DRAWINGS HEAVY UP AND RIGHTU+2517
┛BOX DRAWINGS HEAVY UP AND LEFTU+251B
┣BOX DRAWINGS HEAVY VERTICAL AND RIGHTU+2523
┫BOX DRAWINGS HEAVY VERTICAL AND LEFTU+252B
┳BOX DRAWINGS HEAVY DOWN AND HORIZONTALU+2533
┻BOX DRAWINGS HEAVY UP AND HORIZONTALU+253B
╋BOX DRAWINGS HEAVY VERTICAL AND HORIZONTALU+254B

§R1.3 Double-Line

Used for: Level 3 dialogs, Level 4 modals, active windows (Standard §6.1, §6.2).

GlyphNameUnicode
═BOX DRAWINGS DOUBLE HORIZONTALU+2550
║BOX DRAWINGS DOUBLE VERTICALU+2551
╔BOX DRAWINGS DOUBLE DOWN AND RIGHTU+2554
╗BOX DRAWINGS DOUBLE DOWN AND LEFTU+2557
╚BOX DRAWINGS DOUBLE UP AND RIGHTU+255A
╝BOX DRAWINGS DOUBLE UP AND LEFTU+255D
╠BOX DRAWINGS DOUBLE VERTICAL AND RIGHTU+2560
╣BOX DRAWINGS DOUBLE VERTICAL AND LEFTU+2563
╦BOX DRAWINGS DOUBLE DOWN AND HORIZONTALU+2566
╩BOX DRAWINGS DOUBLE UP AND HORIZONTALU+2569
╬BOX DRAWINGS DOUBLE VERTICAL AND HORIZONTALU+256C

§R1.4 Rounded Corners

Used for: cosmetic non-interactive containers only (Standard §6.6).

GlyphNameUnicode
╭BOX DRAWINGS LIGHT ARC DOWN AND RIGHTU+256D
╮BOX DRAWINGS LIGHT ARC DOWN AND LEFTU+256E
╰BOX DRAWINGS LIGHT ARC UP AND RIGHTU+256F
╯BOX DRAWINGS LIGHT ARC UP AND LEFTU+2570

§R1.5 Dashed Lines

Used for: optional separators, visual grouping within panels.

GlyphNameUnicode
┄BOX DRAWINGS LIGHT TRIPLE DASH HORIZONTALU+2504
┆BOX DRAWINGS LIGHT TRIPLE DASH VERTICALU+2506
┈BOX DRAWINGS LIGHT QUADRUPLE DASH HORIZONTALU+2508
┊BOX DRAWINGS LIGHT QUADRUPLE DASH VERTICALU+250A
╌BOX DRAWINGS HEAVY TRIPLE DASH HORIZONTALU+254C
╎BOX DRAWINGS HEAVY TRIPLE DASH VERTICALU+254E

§R1.6 Block and Shade Characters

Used for: progress bars, sparklines, scroll indicators, shadows.

GlyphNameUnicodeCoverage
░LIGHT SHADEU+259125% fill
▒MEDIUM SHADEU+259250% fill
▓DARK SHADEU+259375% fill
█FULL BLOCKU+2588100% fill
▄LOWER HALF BLOCKU+2584Bottom half
▀UPPER HALF BLOCKU+2580Top half
▌LEFT HALF BLOCKU+258CLeft half
▐RIGHT HALF BLOCKU+2590Right half
▏LEFT ONE EIGHTH BLOCKU+258F1/8 left
▎LEFT ONE QUARTER BLOCKU+258E1/4 left
▍LEFT THREE EIGHTHS BLOCKU+258D3/8 left
▋LEFT FIVE EIGHTHS BLOCKU+258B5/8 left
▊LEFT THREE QUARTERS BLOCKU+258A3/4 left
▉LEFT SEVEN EIGHTHS BLOCKU+25897/8 left

§R1.7 Status and Indicator Symbols

Used for: status displays, selection marks, navigation indicators.

GlyphNameUnicodeUse
◉FISHEYEU+25C9Active/healthy status
○WHITE CIRCLEU+25CBInactive status
●BLACK CIRCLEU+25CFFilled indicator
▸BLACK RIGHT-POINTING SMALL TRIANGLEU+25B8Focus/selection indicator
▴BLACK UP-POINTING SMALL TRIANGLEU+25B4Sort ascending
▾BLACK DOWN-POINTING SMALL TRIANGLEU+25BESort descending
⚠WARNING SIGNU+26A0Warning status
✓CHECK MARKU+2713Success/confirmed
✗BALLOT XU+2717Error/failed
⋯MIDLINE HORIZONTAL ELLIPSISU+22EFTruncation indicator
↑UPWARDS ARROWU+2191Scroll up indicator
↓DOWNWARDS ARROWU+2193Scroll down indicator

§R1.8 Focus Bracket Markers

Used for: alternative focus indication when reverse video is insufficient (Standard §7.2, §8.1).

[▸ focused item ◂]
GlyphNameUnicodePosition
[LEFT SQUARE BRACKETU+005BBefore indicator
▸BLACK RIGHT-POINTING SMALL TRIANGLEU+25B8After opening bracket + space
◂BLACK LEFT-POINTING SMALL TRIANGLEU+25C2Before closing bracket + space
]RIGHT SQUARE BRACKETU+005DAfter indicator

Total width overhead: 6 characters (3 prefix [▸ + 3 suffix ◂]).

§R1.9 Mnemonic Rendering

Mnemonics (Standard §2.4) are underlined letters enabling single-keystroke selection in menus. Source notation uses tilde (~F~ile) or ampersand (&File).

Visual rendering: The mnemonic character MUST be rendered with underline (SGR 4). If the terminal does not support underline, use a contrasting foreground color (bright white when surrounding text is dimmer).

Example — "File" with F as mnemonic:
  Source:  ~F~ile
  Render:  ESC[4mFESC[24mile
           ─────         ────
           underlined F   normal "ile"