Convert and Manipulate SVG Files with Python

Convert and Manipulate SVG Files with Python

SVG (Scalable Vector Graphics) is the standard vector format for the web. Python provides tools to convert SVG to PNG/PDF, edit content, and generate SVG programmatically.

Installation

pip install cairosvg svglib reportlab lxml

Convert SVG to PNG with cairosvg

import cairosvg

# SVG to PNG at 300 DPI
cairosvg.svg2png(
    url="icon.svg",
    write_to="icon.png",
    output_width=512,
    output_height=512,
    dpi=300
)

# From SVG string
svg_code = '<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100"><circle cx="50" cy="50" r="40" fill="blue"/></svg>'
cairosvg.svg2png(bytestring=svg_code.encode(), write_to="circle.png")
print("PNG generated")

Convert SVG to PDF

import cairosvg

cairosvg.svg2pdf(
    url="diagram.svg",
    write_to="diagram.pdf",
    output_width=595,   # A4 in points
    output_height=842
)
print("PDF generated: diagram.pdf")

Convert SVG to WebP and Other Formats

import cairosvg
from PIL import Image
import io

def svg_to_format(svg_path, output, fmt="webp", width=800):
    png_bytes = cairosvg.svg2png(url=svg_path, output_width=width)
    img = Image.open(io.BytesIO(png_bytes))
    img.save(output, format=fmt.upper())
    print(f"SVG converted to {fmt.upper()}: {output}")

svg_to_format("logo.svg", "logo.webp", "webp", 1024)
svg_to_format("logo.svg", "logo.jpg",  "jpeg", 800)

Edit SVG with lxml

from lxml import etree

def change_svg_color(input_file, output_file, old_color, new_color):
    tree = etree.parse(input_file)
    root = tree.getroot()

    for elem in root.iter():
        if elem.get('fill') == old_color:
            elem.set('fill', new_color)
        style = elem.get('style', '')
        if f'fill:{old_color}' in style:
            elem.set('style', style.replace(f'fill:{old_color}', f'fill:{new_color}'))

    tree.write(output_file, pretty_print=True, xml_declaration=True, encoding='utf-8')
    print(f"Color changed: {old_color} -> {new_color}")

change_svg_color("icon.svg", "icon_red.svg", "#0000ff", "#ff0000")

Resize SVG

from lxml import etree

def resize_svg(input_file, output_file, new_width, new_height):
    tree = etree.parse(input_file)
    root = tree.getroot()

    orig_w = float(root.get('width', '100').replace('px',''))
    orig_h = float(root.get('height','100').replace('px',''))

    root.set('width',  str(new_width))
    root.set('height', str(new_height))
    if not root.get('viewBox'):
        root.set('viewBox', f'0 0 {orig_w} {orig_h}')

    tree.write(output_file, pretty_print=True, encoding='utf-8')
    print(f"Resized: {orig_w}x{orig_h} -> {new_width}x{new_height}")

resize_svg("icon.svg", "icon_256.svg", 256, 256)

Generate SVG from Python

def create_bar_chart_svg(data, output, width=400, height=300):
    max_val = max(data.values())
    bar_w   = (width - 60) // len(data)
    lines   = [
        f'<svg xmlns="http://www.w3.org/2000/svg" width="{width}" height="{height}">',
        f'<rect width="{width}" height="{height}" fill="#f8f8f8" stroke="#ddd"/>',
        f'<text x="{width//2}" y="25" text-anchor="middle" font-size="14" fill="#333">Bar Chart</text>',
    ]
    colors = ["#4a9eff", "#ff6b6b", "#51cf66", "#ffd43b", "#cc5de8"]
    for i, (label, value) in enumerate(data.items()):
        bh = int((value / max_val) * (height - 80))
        bx = 30 + i * bar_w
        by = height - 40 - bh
        c  = colors[i % len(colors)]
        lines.append(f'<rect x="{bx}" y="{by}" width="{bar_w-4}" height="{bh}" fill="{c}" rx="3"/>')
        lines.append(f'<text x="{bx+bar_w//2-2}" y="{height-20}" text-anchor="middle" font-size="10" fill="#555">{label}</text>')
        lines.append(f'<text x="{bx+bar_w//2-2}" y="{by-4}" text-anchor="middle" font-size="10" fill="#333">{value}</text>')
    lines.append('</svg>')
    with open(output, 'w', encoding='utf-8') as f:
        f.write('\n'.join(lines))
    print(f"SVG created: {output}")

create_bar_chart_svg({"Jan":120,"Feb":85,"Mar":200,"Apr":150,"May":175}, "sales.svg")

Batch Conversion

import cairosvg
from pathlib import Path

def batch_convert_svgs(folder, output_fmt="png", dpi=96):
    svgs = list(Path(folder).glob("*.svg"))
    for i, svg in enumerate(svgs, 1):
        out = svg.with_suffix(f".{output_fmt}")
        try:
            if output_fmt == "pdf":
                cairosvg.svg2pdf(url=str(svg), write_to=str(out))
            else:
                cairosvg.svg2png(url=str(svg), write_to=str(out), dpi=dpi)
            print(f"  [{i}/{len(svgs)}] {svg.name} -> {out.name}")
        except Exception as e:
            print(f"  [{i}] ERROR {svg.name}: {e}")

batch_convert_svgs("icons/", "png", 144)

Additional Resource

For converting SVG files to PNG, PDF or WebP without any coding, use KaijuConverter — free and no registration required.

Related conversions

Most teams that read this guide convert images in one of these directions:

• JPG to WEBP
• PNG to JPG
• HEIC to JPG
• PNG to WEBP
• TIFF to PNG
• RAW to JPG