SVG Architecture Diagram

Create professional, publication-quality technical architecture diagrams using pure SVG in HTML, then screenshot via Playwright. Produces crisp, pixel-perfect diagrams with precise connection lines, color-coded modules, and clear text at any resolution. Use when: (1) user asks for a system architecture diagram, (2) user wants a technical component diagram or flow chart, (3) user needs a data flow or pipeline visualization, (4) any diagram requiring accurate text labels and precise connecting lines. Triggers: "architecture diagram", "架构图", "技术架构", "system diagram", "component diagram", "flow diagram", "数据流图", "模块图", "draw architecture", "画架构图", "technical diagram". Prefer this over AI image generation for any diagram with text labels.

Garming@wujiaming88

Install

openclaw skills install @wujiaming88/svg-architecture-diagram

SVG Architecture Diagram

Create professional technical architecture diagrams using pure SVG, rendered to high-res PNG via Playwright.

Why SVG (not CSS positioning or AI image generation)

Approach	Lines/Arrows	Text Quality	Precision
SVG (this skill)	✅ Perfect: `<line>`, `<path>`, `<marker>`	✅ Crisp at any size	✅ Pixel-perfect
CSS absolute positioning	❌ Hacky: borders, pseudo-elements	✅ OK	❌ Hard to align
AI image generation	❌ No control	❌ Garbled text	❌ No precision

Quick Start

Step 1: Plan the diagram

Identify:

Modules — group related components (color-coded)
Hierarchy — top-to-bottom flow (user → core → subsystems → output)
Connections — data flow (solid lines), feedback (dashed lines)

Step 2: Create the HTML file

Write a single HTML file with an inline SVG. Standard canvas: 1600×1000px.

html

<!DOCTYPE html>
<html><head>
<meta charset="UTF-8">
<style>
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');
* { margin: 0; padding: 0; box-sizing: border-box; }
body { width: 1600px; height: 1000px; background: #fafafa; overflow: hidden; }
</style>
</head><body>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1600 1000" width="1600" height="1000">
  <defs>
    <!-- Arrow markers — one per color -->
    <marker id="arr-indigo" markerWidth="8" markerHeight="6" refX="7" refY="3" orient="auto">
      <path d="M0,0 L8,3 L0,6 Z" fill="#6366f1"/>
    </marker>
    <!-- Shadow filter -->
    <filter id="shadow" x="-4%" y="-4%" width="108%" height="108%">
      <feDropShadow dx="0" dy="2" stdDeviation="4" flood-color="#000" flood-opacity="0.08"/>
    </filter>
  </defs>

  <!-- Diagram content here -->

</svg>
</body></html>

Step 3: Build the diagram using these SVG patterns

Filled header card (module title):

svg

<rect x="X" y="Y" width="W" height="40" rx="10" fill="#6366f1" filter="url(#shadow)"/>
<text x="CENTER" y="Y+25" text-anchor="middle" font-size="13" font-weight="700" fill="#fff">🔄 Module Name</text>

Outlined detail card (sub-component):

svg

<rect x="X" y="Y" width="W" height="65" rx="10" fill="#fff" stroke="#6366f1" stroke-width="2" filter="url(#shadow)"/>
<text x="X+20" y="Y+22" font-size="12" font-weight="700" fill="#6366f1">Component Title</text>
<text x="X+20" y="Y+40" font-size="11" fill="#6b7280">Description line 1</text>
<text x="X+20" y="Y+55" font-size="10" fill="#9ca3af">Metadata / specs</text>

Connection line (with arrow):

svg

<line x1="FROM_X" y1="FROM_Y" x2="TO_X" y2="TO_Y" stroke="#6366f1" stroke-width="2" marker-end="url(#arr-indigo)"/>

Curved connection (L-shape or bend):

svg

<path d="M startX,startY L midX,midY L endX,endY" stroke="#6366f1" stroke-width="2" fill="none" marker-end="url(#arr-indigo)"/>

Dashed feedback line:

svg

<path d="M x1,y1 L x2,y2" stroke="#8b5cf6" stroke-width="2" fill="none" stroke-dasharray="6,4" marker-end="url(#arr-purple)"/>

Connection label:

svg

<text x="MID_X" y="MID_Y-5" font-size="10" fill="#6366f1" font-weight="500">label text</text>

Step 4: Screenshot with Playwright

python

from playwright.sync_api import sync_playwright
with sync_playwright() as p:
    browser = p.chromium.launch()
    page = browser.new_page(
        viewport={"width": 1600, "height": 1000},
        device_scale_factor=4,  # 4x ultra-high res (default)
    )
    page.goto("file:///path/to/diagram.html", wait_until="networkidle")
    page.wait_for_timeout(1500)
    page.screenshot(path="diagram.png", full_page=True)
    browser.close()

Or use the bundled script: scripts/screenshot.py <input.html> [output.png]

Design System

See references/design-system.md for the complete color palette, card styles, arrow markers, and text sizing rules.

Critical Rules (prevent common issues)

Text Overflow Prevention

Max characters per line at font-size 11px ≈ 7px/char:
- 300px container → max 37 chars
- 340px container → max 43 chars
- 440px container → max 57 chars
Long text → split into multiple <text> elements with Y offset +15px each
Always leave 20px padding on each side of text inside cards
Test at 1x scale before generating final 4x screenshot

Connection Line Rules

Never use CSS for connections — always SVG <line> or <path>
One <marker> per color — define in <defs>, reference with marker-end
Straight lines when possible; use <path> L-segments for bends
Avoid crossing lines — rearrange layout if lines would cross
Label every connection — brief verb/noun near the midpoint
⚠️ Minimum 20px gap between vertically stacked cards — Arrow markers are 8px long. If the gap between cards is less than 20px, the arrow will completely cover the line, making it look like "arrow only, no line". Use card height 34px + gap 22px = 56px per step.
Connection line length must be at least 17px — This ensures 9px visible line + 8px arrow marker. Example: card bottom at y=324, next card top at y=346, line from y1=324 to y2=343 (19px).
Never make line length < marker size (8px) — The line will be invisible.

Layout Rules

Top-to-bottom primary flow (input at top, output at bottom/right)
Left-right symmetry when possible
Group related modules vertically (e.g., memory layers stacked)
Minimum 20px gap between vertically stacked cards (see Connection Line Rules)
Color-code by function — see design system for standard palette
Include a legend (bottom-right corner) explaining colors and line types
Include a title (top center) and source attribution (bottom center)

Font Rules

Font family: font-family="Inter, 'PingFang SC', 'Microsoft YaHei', sans-serif" — set on root <svg> or first <text>
Load Inter via Google Fonts in <style> block
Chinese text: use PingFang SC / Microsoft YaHei fallback
Font sizes: titles 13-14px, descriptions 10-11px, metadata 9-10px

Examples

Two complete working examples are included:

references/example-hermes.html — Hermes Agent architecture (6 modules, medium complexity)
references/example-openclaw.html — OpenClaw platform architecture (12 modules, high complexity, demonstrates proper vertical card spacing for Agent Loop steps)

Delivery

Output MEDIA:<path> for inline delivery, or openclaw message send --channel telegram --target <id> --media <path> --force-document for Telegram.

If PNG exceeds ~1MB for Telegram delivery, convert to JPEG (quality=95):

python

from PIL import Image
img = Image.open("diagram.png")
img.save("diagram.jpg", "JPEG", quality=95, optimize=True)

Default is 4x (6400×4000px for 1600×1000 canvas). Always use maximum resolution.

SVG Architecture Diagram

Install

SVG Architecture Diagram

Why SVG (not CSS positioning or AI image generation)

Quick Start

Step 1: Plan the diagram

Step 2: Create the HTML file

Step 3: Build the diagram using these SVG patterns

Step 4: Screenshot with Playwright

Design System

Critical Rules (prevent common issues)

Text Overflow Prevention

Connection Line Rules

Layout Rules

Font Rules

Examples

Delivery

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