svg（SVG 命令行）

SVG Creation Guide

Create clean, scalable SVG that is easy to edit, prints well, and survives “real-world” tooling (PowerPoint, browser, PDF export, HMI toolchains).

Working rules (keep SVG dependable)

• Use a viewBox on every SVG.
• Keep geometry simple: prefer path, rect, circle, line, polyline, polygon.
• Prefer strokes for technical drawings; prefer fills for pictograms.
• Use consistent naming and grouping: id on key groups, class for reusable styling.
• Avoid renderer-fragile features unless asked:

- Avoid: filter, mask, clipPath, foreignObject, blend modes, external images/fonts. - Use gradients sparingly; keep them simple (linearGradient/radialGradient).

• Keep decimal precision reasonable (typically 2–3 decimals). Do not over-optimize readability away.

Requirements to capture (ask only what matters)

Capture enough to produce the correct output on the first pass.

1. Target environment (drives compatibility)

- Web / inline HTML - PowerPoint / Office - HMI/SCADA tool (name/version if known) - Engineering doc pipeline (PDF export, Visio, etc.)

1. Canvas + scale Useful conversions (SVG assumes 96 DPI for CSS pixels):

- Desired physical size (mm/in) or slide size intent - Coordinate system preference (e.g., “0–100 grid”, “millimeters”, “pixels”) - Any snapping/grid requirements - $1,\text{in} = 96,\text{px}$ - $1,\text{mm} = 96/25.4 \approx 3.7795,\text{px}$

1. Styling constraints

- Stroke widths (e.g., 1.5 for primary lines, 1.0 for secondary) - Line caps/joins (round vs square) - Color palette (include corporate colors if relevant) - Light/dark background expectations

1. Content + semantics

- What objects exist (symbols, instruments, pipes, arrows, labels) - Layering needs (background, pipework, instrumentation, callouts) - Text rules (font family, size, casing, alignment)

1. Deliverables

- Number of variants (size/layout/color) - Editable text vs outlined text requirements - File naming convention and destination folder

Output patterns (choose the right one)

Pattern A: Technical diagram / P&ID style

Use strokes, consistent line weights, and a simple palette. Prefer vector-effect="non-scaling-stroke" when objects will be scaled.

Key tips:

• Keep symbols as <g id="symbol-*"> groups.
• Use stroke="currentColor" on symbols when you want themeable line art.
• Align to a grid; keep elbows crisp with polyline.

Pattern B: PowerPoint/Office-friendly illustration

Prioritize compatibility:

• Prefer inline presentation attributes (fill, stroke, stroke-width) over heavy CSS.
• Avoid: masks/filters, complex gradients, marker arrows (Office support varies).
• Keep text as <text> if the user wants to edit labels in PPT.
• If the user needs pixel-perfect portability, provide an “outlined” version (text converted to paths) and warn it is no longer editable.

Pattern C: HMI/SCADA widget

Design for clarity at small sizes and for interaction:

• Use generous hit areas (transparent rect with fill="transparent" for click/touch zones).
• Keep state styling isolated (.state-ok, .state-alarm, .state-disabled).
• Separate “skin” from “labels” so integrators can map tags and states.

SVG skeleton (recommended)

Use this as the default structure.

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 300 200" width="300" height="200" role="img" aria-labelledby="title desc">
  <title id="title">Diagram title</title>
  <desc id="desc">Short description of what is shown</desc>

  <defs>
    <style>
      .line { fill: none; stroke: #111827; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
      .thin { stroke-width: 1; }
      .fill { fill: #F3F4F6; }
      .text { fill: #111827; font-family: Arial, sans-serif; font-size: 12px; }
    </style>
  </defs>

  <g id="layer-background"></g>
  <g id="layer-geometry"></g>
  <g id="layer-annotations"></g>
</svg>

If targeting PowerPoint/Office and compatibility is uncertain, repeat critical attributes inline on elements (Office can be picky about CSS).

Reference examples (copy/paste building blocks)

1) P&ID-style pipe with arrow and tag

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 240 80" width="240" height="80">
  <g id="pipe" stroke="#111827" stroke-width="3" fill="none" stroke-linecap="round" stroke-linejoin="round" vector-effect="non-scaling-stroke">
    <polyline points="20,40 160,40" />
    <!-- arrow head (Office-friendly: polygon instead of marker) -->
    <polygon points="160,32 160,48 178,40" fill="#111827" stroke="none" />
  </g>

  <g id="tag">
    <rect x="185" y="24" width="45" height="32" rx="6" fill="#FFFFFF" stroke="#111827" stroke-width="2" />
    <text x="207.5" y="45" text-anchor="middle" font-family="Arial, sans-serif" font-size="12" fill="#111827">P-101</text>
  </g>
</svg>

2) Simple valve symbol (line-art)

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 120 40" width="120" height="40">
  <g id="valve" stroke="#111827" stroke-width="3" fill="none" stroke-linecap="round" stroke-linejoin="round" vector-effect="non-scaling-stroke">
    <line x1="10" y1="20" x2="35" y2="20" />
    <line x1="85" y1="20" x2="110" y2="20" />
    <polygon points="35,8 60,20 35,32" />
    <polygon points="85,8 60,20 85,32" />
  </g>
</svg>

3) HMI button (states via classes)

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 220 70" width="220" height="70">
  <defs>
    <style>
      .btn { stroke: #0F172A; stroke-width: 2; rx: 12; }
      .ok { fill: #22C55E; }
      .alarm { fill: #EF4444; }
      .disabled { fill: #CBD5E1; }
      .label { fill: #0F172A; font-family: Arial, sans-serif; font-size: 16px; font-weight: 700; }
    </style>
  </defs>

  <g id="button" class="ok">
    <rect class="btn ok" x="10" y="10" width="200" height="50" />
    <text class="label" x="110" y="42" text-anchor="middle" dominant-baseline="middle">START</text>
    <!-- hit area -->
    <rect x="10" y="10" width="200" height="50" fill="transparent" />
  </g>
</svg>

Quality checklist (run mentally before delivering)

• Include viewBox; ensure shapes fit the viewBox with sane margins.
• Keep stroke widths consistent and intentional.
• Ensure text alignment is correct (text-anchor, dominant-baseline).
• Keep groups layered predictably (layer-*).
• Avoid external dependencies (no linked fonts/images) unless requested.
• If PowerPoint/Office is the target, avoid unsupported features and prefer inline attributes.

File outputs

When saving multiple variants, use a naming convention that encodes intent:

• asset-name__v1__editable.svg
• asset-name__v1__outlined.svg
• asset-name__dark.svg
• asset-name__light.svg
• asset-name__scale-0-100.svg

Save files into a logical folder (e.g., assets/svg/ or a user-specified directory).