Add SVG combination tool and plate dimension options

Created combine_svg_vertical.py to vertically stack SVG files with centering
and configurable spacing. Enhanced svg_logo_to_stl.py with plate dimensions
and margin options for better nameplate creation.

combine_svg_vertical.py features:
- Vertically combines two SVG files (icon above text)
- Automatically centers smaller element
- Configurable spacing between elements (default: 20px)
- Configurable margin around composition (default: 10px)
- Preserves individual SVG structure in groups

svg_logo_to_stl.py enhancements:
- Added --plate-width and --plate-height options
- Logo scales to fit within plate dimensions (maintaining aspect ratio)
- Added --margin option for spacing around logo on plate
- Automatic centering of logo on plate
- Reports actual dimensions: plate, logo, margin, and offset

Example usage:
  # Combine icon and text
  python combine_svg_vertical.py um_grey.svg um_black.svg combined.svg --spacing 114

  # Center on 256x256mm plate with 10mm margin
  python svg_logo_to_stl.py combined.svg output \
    --plate-width 256 --plate-height 256 --margin 10 \
    --base-thickness 1.5 --feature-height 2.5

Files:
- combine_svg_vertical.py: Vertical SVG stacking tool
- README_combine_svg.md: Documentation for combine tool
- underground-magnetics-combined.svg: Example combined logo
- svg_logo_to_stl.py: Enhanced with plate dimensions
- command.txt: Updated with new parameters

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

combine_svg_vertical.py

@@ -0,0 +1,145 @@
+#!/usr/bin/env python3
+"""
+Combine two SVG files vertically (top over bottom) with centering and spacing.
+Useful for combining separated logo elements for 3D printing.
+"""
+
+import argparse
+import xml.etree.ElementTree as ET
+from pathlib import Path
+
+
+def load_svg(svg_path: Path):
+    """Load SVG and extract its dimensions and content"""
+    tree = ET.parse(svg_path)
+    root = tree.getroot()
+
+    # Get dimensions from viewBox or width/height attributes
+    viewbox = root.get('viewBox')
+    if viewbox:
+        parts = viewbox.split()
+        x, y, width, height = map(float, parts)
+    else:
+        width = float(root.get('width', 0))
+        height = float(root.get('height', 0))
+        x, y = 0, 0
+
+    return {
+        'root': root,
+        'width': width,
+        'height': height,
+        'viewbox_x': x,
+        'viewbox_y': y
+    }
+
+
+def combine_svgs_vertical(top_svg_path: Path, bottom_svg_path: Path, output_path: Path,
+                         spacing: float = 20, margin: float = 10):
+    """
+    Combine two SVGs vertically with the top one centered above the bottom one.
+
+    Args:
+        top_svg_path: Path to top SVG (e.g., icon)
+        bottom_svg_path: Path to bottom SVG (e.g., text)
+        output_path: Path for output combined SVG
+        spacing: Vertical space between top and bottom elements (default: 20)
+        margin: Margin around the entire composition (default: 10)
+    """
+    # Load both SVGs
+    top_svg = load_svg(top_svg_path)
+    bottom_svg = load_svg(bottom_svg_path)
+
+    # Calculate combined dimensions
+    max_width = max(top_svg['width'], bottom_svg['width'])
+    combined_height = top_svg['height'] + spacing + bottom_svg['height']
+
+    # Add margins
+    canvas_width = max_width + (2 * margin)
+    canvas_height = combined_height + (2 * margin)
+
+    # Calculate centering offsets
+    top_x_offset = margin + (max_width - top_svg['width']) / 2
+    top_y_offset = margin
+
+    bottom_x_offset = margin + (max_width - bottom_svg['width']) / 2
+    bottom_y_offset = margin + top_svg['height'] + spacing
+
+    # Create new SVG root
+    combined = ET.Element('svg', {
+        'xmlns': 'http://www.w3.org/2000/svg',
+        'width': str(canvas_width),
+        'height': str(canvas_height),
+        'viewBox': f'0 0 {canvas_width} {canvas_height}'
+    })
+
+    # Add comment for clarity
+    comment = ET.Comment(f' Combined: {top_svg_path.name} (top) + {bottom_svg_path.name} (bottom) ')
+    combined.append(comment)
+
+    # Create group for top SVG with transform
+    top_group = ET.SubElement(combined, 'g', {
+        'id': 'top',
+        'transform': f'translate({top_x_offset}, {top_y_offset})'
+    })
+
+    # Copy all elements from top SVG
+    for child in top_svg['root']:
+        if child.tag != '{http://www.w3.org/2000/svg}metadata':
+            top_group.append(child)
+
+    # Create group for bottom SVG with transform
+    bottom_group = ET.SubElement(combined, 'g', {
+        'id': 'bottom',
+        'transform': f'translate({bottom_x_offset}, {bottom_y_offset})'
+    })
+
+    # Copy all elements from bottom SVG
+    for child in bottom_svg['root']:
+        if child.tag != '{http://www.w3.org/2000/svg}metadata':
+            bottom_group.append(child)
+
+    # Write output
+    tree = ET.ElementTree(combined)
+    ET.indent(tree, space='  ')
+    tree.write(output_path, encoding='utf-8', xml_declaration=True)
+
+    print(f"Created {output_path}")
+    print(f"  Top ({top_svg_path.name}): {top_svg['width']:.0f}x{top_svg['height']:.0f} at ({top_x_offset:.1f}, {top_y_offset:.1f})")
+    print(f"  Bottom ({bottom_svg_path.name}): {bottom_svg['width']:.0f}x{bottom_svg['height']:.0f} at ({bottom_x_offset:.1f}, {bottom_y_offset:.1f})")
+    print(f"  Canvas: {canvas_width:.0f}x{canvas_height:.0f}")
+    print(f"  Spacing: {spacing:.0f}, Margin: {margin:.0f}")
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description='Combine two SVG files vertically with centering and spacing'
+    )
+    parser.add_argument('top', help='Top SVG file (e.g., icon)')
+    parser.add_argument('bottom', help='Bottom SVG file (e.g., text)')
+    parser.add_argument('output', help='Output SVG file')
+    parser.add_argument('--spacing', '-s', type=float, default=20,
+                       help='Vertical spacing between elements (default: 20)')
+    parser.add_argument('--margin', '-m', type=float, default=10,
+                       help='Margin around entire composition (default: 10)')
+
+    args = parser.parse_args()
+
+    top_path = Path(args.top)
+    bottom_path = Path(args.bottom)
+    output_path = Path(args.output)
+
+    if not top_path.exists():
+        print(f"ERROR: Top SVG file not found: {top_path}")
+        return 1
+
+    if not bottom_path.exists():
+        print(f"ERROR: Bottom SVG file not found: {bottom_path}")
+        return 1
+
+    combine_svgs_vertical(top_path, bottom_path, output_path, args.spacing, args.margin)
+
+    return 0
+
+
+if __name__ == '__main__':
+    exit(main())