ASCII Diagrams & Text Visualization

Create and repair pixel-perfect monospace diagrams, tables, and wireframes.

Core Principle

Every character counts. In monospace, misaligned borders break visual structure instantly.

Validation Script

Always validate diagrams before committing:

python scripts/validate_boxes.py <file.md>        # Check for issues
python scripts/validate_boxes.py <file.md> --fix  # Auto-fix width issues

Quick Reference: Box Drawing Characters

Corners:  ┌ ┐ └ ┘  (light)     ╔ ╗ ╚ ╝  (double)
Lines:    ─ │      (light)     ═ ║      (double)
T-joins:  ┬ ┴ ├ ┤  (light)     ╦ ╩ ╠ ╣  (double)
Cross:    ┼        (light)     ╬        (double)
Rounded:  ╭ ╮ ╰ ╯  (rounded corners)

Creating Tables

Standard Table Pattern

┌─────────────┬────────────┬───────┐
│ Column 1    │ Column 2   │ Col 3 │
├─────────────┼────────────┼───────┤
│ Value here  │ Another    │ 123   │
│ More data   │ Content    │ 456   │
└─────────────┴────────────┴───────┘

Construction rules:

1. Count characters in widest cell per column
2. Add 1 space padding on each side (cell width + 2)
3. Draw top border:

   ┌

   +

   ─

   × width +

   ┬

   between columns +

   ┐

4. Draw header row with

   │

   separators
5. Draw separator:

   ├

   +

   ─

   × width +

   ┼

   between columns +

   ┤

6. Draw data rows
7. Draw bottom:

   └

   +

   ─

   × width +

   ┴

   between columns +

   ┘

Markdown-Compatible Table

When ASCII boxes render poorly, use pipe tables:

| Status      | Count | Action   |
|-------------|-------|----------|
| Connected   | 42    | None     |
| Pending     | 7     | Review   |

Creating Wireframes

Modal/Dialog Pattern

╭────────────────────────────────────────╮
│  Modal Title                        ✕  │
├────────────────────────────────────────┤
│                                        │
│  Content area with description         │
│  text that explains the action.        │
│                                        │
│  ┌──────────────────────────────────┐  │
│  │ Input field                      │  │
│  └──────────────────────────────────┘  │
│                                        │
│               [Cancel]  [Confirm]      │
│                                        │
╰────────────────────────────────────────╯

Card Pattern

┌──────────────────────────────────┐
│ ◉ Card Title             [···]  │
├──────────────────────────────────┤
│                                  │
│  Card content goes here with    │
│  multiple lines of text.        │
│                                  │
│  ● Status: Active               │
│  ○ Priority: Medium             │
│                                  │
└──────────────────────────────────┘

Layout Grid

┌────────────────────────────────────────────────┐
│                    Header                      │
├────────────┬───────────────────────────────────┤
│            │                                   │
│  Sidebar   │         Main Content              │
│            │                                   │
│  ○ Nav 1   │   ┌──────────┐  ┌──────────┐     │
│  ● Nav 2   │   │  Card 1  │  │  Card 2  │     │
│  ○ Nav 3   │   └──────────┘  └──────────┘     │
│            │                                   │
├────────────┴───────────────────────────────────┤
│                    Footer                      │
└────────────────────────────────────────────────┘

Creating Flow Diagrams

Horizontal Flow

┌─────────┐     ┌─────────┐     ┌─────────┐
│  Start  │────▶│ Process │────▶│   End   │
└─────────┘     └─────────┘     └─────────┘

Vertical Flow with Branching

          ┌─────────┐
          │  Input  │
          └────┬────┘
               │
               ▼
          ┌─────────┐
          │ Decide  │
          └────┬────┘
               │
         ┌─────┴─────┐
         ▼           ▼
   ┌─────────┐ ┌─────────┐
   │   Yes   │ │   No    │
   └────┬────┘ └────┬────┘
        │           │
        └─────┬─────┘
              ▼
          ┌─────────┐
          │ Output  │
          └─────────┘

Architecture Diagram

┌───────────────────────────────────────────────┐
│                  Frontend                     │
│  ┌──────────┐  ┌──────────┐  ┌──────────┐    │
│  │  React   │  │  Zustand │  │  Query   │    │
│  └────┬─────┘  └────┬─────┘  └────┬─────┘    │
└───────┼─────────────┼─────────────┼───────────┘
        │             │             │
        └─────────────┼─────────────┘
                      │ HTTP/WS
                      ▼
┌───────────────────────────────────────────────┐
│                  Backend                      │
│  ┌──────────┐  ┌──────────┐  ┌──────────┐    │
│  │ FastAPI  │──│ Services │──│  Models  │    │
│  └──────────┘  └────┬─────┘  └────┬─────┘    │
└─────────────────────┼─────────────┼───────────┘
                      │             │
        ┌─────────────┴─────────────┘
        ▼             ▼             ▼
   ┌─────────┐   ┌─────────┐   ┌─────────┐
   │ Postgres│   │  NATS   │   │  Redis  │
   └─────────┘   └─────────┘   └─────────┘

Special Elements

Icons & Indicators

Status:     ● active   ○ inactive   ◐ partial
Checkbox:   ☑ checked  ☐ unchecked  ☒ disabled
Arrows:     → ← ↑ ↓    ▶ ◀ ▲ ▼      ➜ ➤
Progress:   ▓▓▓▓▓░░░░░ (50%)
Stars:      ★★★☆☆ (3/5)
Bullets:    • ◦ ‣ ⁃

Button Representations

Standard:  [Button]    [  OK  ]   [Cancel]
Primary:   【Submit】   ⟦ Action ⟧
Rounded:   ( Click )   (  Go  )

Fixing Broken Diagrams

CRITICAL: Always Diagnose First

Before manually fixing, run this diagnostic:

python3 << 'EOF'
diagram = """
PASTE_DIAGRAM_HERE
"""
print("Line-by-line analysis:\n")
for i, line in enumerate(diagram.strip().split('\n'), 1):
    has_broken = '�' in line or '\ufffd' in line
    marker = '⚠️  BROKEN CHAR' if has_broken else ''
    print(f"{i:2d}: len={len(line):3d} {marker}")
    if has_broken:
        # Find position of broken chars
        for j, c in enumerate(line):
            if c == '�' or ord(c) == 0xFFFD:
                print(f"    Position {j}: replacement character (corrupted Unicode)")
EOF

Common diagnostic findings:

len

⚠️ BROKEN CHAR

�

─

Diagnostic Checklist

1. Count border lengths - top

   ─

   count must equal bottom
2. Check vertical alignment - all

   │

   must be in same column
3. Verify corner usage -

   ┌┐

   top,

   └┘

   bottom, never mixed
4. Match cell widths - every row same total width
5. Consistent spacing - same padding in all cells
6. No broken chars - search for

   �

   (U+FFFD replacement character)

Common Issues & Fixes

Issue: Jagged right edge

❌ BROKEN                     ✅ FIXED
┌───────────────────┐        ┌───────────────────┐
│ Short          │           │ Short             │
│ Much longer text│           │ Much longer text  │
└──────────────────┘          └───────────────────┘

Fix: Pad shorter lines with spaces to match longest line.

Issue: Mismatched borders

❌ BROKEN                     ✅ FIXED
┌───────────────────┐        ┌───────────────────┐
│ Content          |         │ Content           │
└──────────────────-┘         └───────────────────┘

Fix: Use consistent box characters (

│

|

─

-

Issue: Wrong corner characters

❌ BROKEN                     ✅ FIXED
+-------------------+        ┌───────────────────┐
| Content           |        │ Content           │
+-------------------+        └───────────────────┘

Fix: Replace ASCII

+

-

|

Validation Checklist

Before committing any ASCII diagram:

□ All horizontal borders same length
□ All vertical bars aligned in columns
□ Corners use correct characters (┌┐└┘)
□ Content properly padded with spaces
□ No mixed ASCII/Unicode border chars
□ Renders correctly in monospace font
□ Width fits target display (80-120 chars typical)
□ Run: python scripts/validate_boxes.py <file>

Width Guidelines

Pro Tips

1. Draft in stages - Draw outer box first, then inner structure
2. Use placeholders - Mark widths with

   XXX

   then replace
3. Copy working patterns - Start from examples above
4. Validate always - Run

   validate_boxes.py

   before saving
5. Consider alternatives - Sometimes Mermaid/PlantUML better for complex diagrams