---

name: create-2d-composition locale: caveman-ultra source_locale: en source_commit: "75ded7a1" fence_basis_commit: 75ded7a1 translator: "Julius Brussee homage — caveman" translation_date: "2026-04-19" description: > Compose 2D graphics programmatically using SVG generation, diagram layout algorithms, image compositing, and batch processing workflows. Use when generating diagrams, flowcharts, or infographics programmatically, creating reproducible scientific figures, automating production of badges or visual assets, building custom chart types not in standard libraries, or batch generating graphics with parameter variations. license: MIT allowed-tools: Read Write Edit Bash Grep Glob metadata: author: Philipp Thoss version: "1.0" domain: visualization complexity: intermediate language: Python tags: svg, 2d, graphics, composition, diagrams, scripting, batch-processing

Create 2D Composition

2D graphics via SVG + layout + compositing + batch → charts, diagrams, infographics.

Use When

• Diagrams/flowcharts/infographics programmatic
• Repro scientific figures
• Auto badges/icons/assets
• Composite imgs / data viz
• Custom chart types (not in libs)
• Batch gen w/ param variations
• SVG templates web/print

In

In	Type	Desc	Example
Layout spec	Config	Dims, margins, grid	800x600px canvas, 20px margins
Visual elements	Data/Assets	Shapes, text, imgs, pts	Rect coords, labels, icons
Style params	CSS/Attrs	Colors, fonts, stroke, opacity	fill="#3366cc", stroke-width="2"
Data sources	Files/Arrays	Values → viz	CSV, JSON config
Out format	String	SVG/PNG/PDF	output.svg, 300 DPI PNG

Do

1. Python Env Setup

# Core libraries
pip install svgwrite pillow cairosvg

# Optional: advanced features
pip install drawsvg reportlab pycairo

# For data-driven graphics
pip install matplotlib numpy pandas

Got: Libs installed If err: Check Python 3.7+, use venv

2. Basic SVG

import svgwrite
from svgwrite import cm, mm

def create_basic_svg(output_path):
    """Create a simple SVG graphic."""
    # Initialize drawing (use mm for precise dimensions)
    dwg = svgwrite.Drawing(output_path, size=('180mm', '120mm'), profile='full')

    # Add background rectangle
    dwg.add(dwg.rect(
        insert=(0, 0),
        size=('100%', '100%'),
        fill='white'
    ))

    # Add shapes
    dwg.add(dwg.circle(
        center=(90*mm, 60*mm),
        r=30*mm,
        fill='lightblue',
        stroke='navy',
        stroke_width=2
    ))

    dwg.add(dwg.rect(
        insert=(30*mm, 30*mm),
        size=(60*mm, 40*mm),
        fill='lightgreen',
        stroke='darkgreen',
        stroke_width=2,
        rx=5,  # Rounded corners
        ry=5
    ))

    # Add text
    dwg.add(dwg.text(
        'Example Graphic',
        insert=(90*mm, 20*mm),
        text_anchor='middle',
        font_size='18pt',
        font_family='Arial',
        fill='black'
    ))

    dwg.save()
    print(f"Saved: {output_path}")

Got: SVG w/ shapes + text If err: Check svgwrite ver, out dir writable

3. Diagram Layout

def create_flowchart(steps, output_path):
    """Generate a flowchart from list of steps."""
    dwg = svgwrite.Drawing(output_path, size=('800px', '600px'))

    # Layout parameters
    box_width = 120
    box_height = 60
    spacing_y = 100
    start_x = 340
    start_y = 50

    for i, step in enumerate(steps):
        y_pos = start_y + i * spacing_y

        # Draw box
        box = dwg.add(dwg.g(id=f'step_{i}'))

        box.add(dwg.rect(
            insert=(start_x, y_pos),
            size=(box_width, box_height),
            fill='lightblue',
            stroke='navy',
            stroke_width=2,
            rx=5,
            ry=5
        ))

        # Add text (wrapped if needed)
        text_lines = wrap_text(step, max_width=16)
        text_y = y_pos + box_height/2 - (len(text_lines)-1) * 7

        for j, line in enumerate(text_lines):
            box.add(dwg.text(
                line,
                insert=(start_x + box_width/2, text_y + j*14),
                text_anchor='middle',
                font_size='12pt',
                font_family='Arial',
                fill='black'
            ))

        # Draw arrow to next step
        if i < len(steps) - 1:
            arrow_start_y = y_pos + box_height
            arrow_end_y = y_pos + spacing_y

            dwg.add(dwg.line(
                start=(start_x + box_width/2, arrow_start_y),
                end=(start_x + box_width/2, arrow_end_y),
                stroke='black',
                stroke_width=2,
                marker_end=dwg.marker(
                    id='arrow',
                    viewBox='0 0 10 10',
                    refX=5,
                    refY=5,
                    markerWidth=6,
                    markerHeight=6,
                    orient='auto'
                )
            ))

    dwg.save()

def wrap_text(text, max_width=20):
    """Simple text wrapping."""
    words = text.split()
    lines = []
    current_line = []

    for word in words:
        test_line = ' '.join(current_line + [word])
        if len(test_line) <= max_width:
            current_line.append(word)
        else:
            if current_line:
                lines.append(' '.join(current_line))
            current_line = [word]

    if current_line:
        lines.append(' '.join(current_line))

    return lines

Got: Flowchart w/ boxes + arrows If err: Adjust layout calc, verify arrow markers

4. Composite Raster

Full Pillow composite (grid/horiz/vert + annotate) → references/EXAMPLES.md.

Got: Composite img w/ layout If err: Check inputs exist, img modes compat

5. Data-Driven Graphics

import numpy as np

def create_bar_chart_svg(data, labels, output_path):
    """Generate SVG bar chart from data."""
    dwg = svgwrite.Drawing(output_path, size=('600px', '400px'))

    # Chart area
    margin = 50
    chart_width = 500
    chart_height = 300
    bar_spacing = 10

    # Calculate bar dimensions
    n_bars = len(data)
    bar_width = (chart_width - (n_bars - 1) * bar_spacing) / n_bars

    # Scale data to fit chart
    max_value = max(data)
    scale = chart_height / max_value

    # Draw axes
    dwg.add(dwg.line(
        start=(margin, margin),
        end=(margin, margin + chart_height),
        stroke='black',
        stroke_width=2
    ))
    dwg.add(dwg.line(
        start=(margin, margin + chart_height),
        end=(margin + chart_width, margin + chart_height),
        stroke='black',
        stroke_width=2
    ))

    # Draw bars
    for i, (value, label) in enumerate(zip(data, labels)):
        x = margin + i * (bar_width + bar_spacing)
        bar_height = value * scale
        y = margin + chart_height - bar_height

        # Bar
        dwg.add(dwg.rect(
            insert=(x, y),
            size=(bar_width, bar_height),
            fill='steelblue',
            stroke='navy',
            stroke_width=1
        ))

        # Value label
        dwg.add(dwg.text(
            f'{value:.1f}',
            insert=(x + bar_width/2, y - 5),
            text_anchor='middle',
            font_size='10pt',
            fill='black'
        ))

        # X-axis label
        dwg.add(dwg.text(
            label,
            insert=(x + bar_width/2, margin + chart_height + 20),
            text_anchor='middle',
            font_size='10pt',
            fill='black'
        ))

    dwg.save()

Got: SVG bar chart scaled If err: Handle edge cases (empty, neg), add validate

6. Batch Gen

def batch_generate_badges(users, template_path, output_dir):
    """Generate badge for each user."""
    os.makedirs(output_dir, exist_ok=True)

    for user in users:
        output_path = os.path.join(output_dir, f"{user['id']}_badge.svg")

        dwg = svgwrite.Drawing(output_path, size=('300px', '100px'))

        # Background
        dwg.add(dwg.rect(
            insert=(0, 0),
            size=('100%', '100%'),
            fill='#3366cc',
            rx=10,
            ry=10
        ))

        # User name
        dwg.add(dwg.text(
            user['name'],
            insert=(150, 40),
            text_anchor='middle',
            font_size='20pt',
            font_weight='bold',
            fill='white'
        ))

        # User role
        dwg.add(dwg.text(
            user['role'],
            insert=(150, 70),
            text_anchor='middle',
            font_size='14pt',
            fill='lightblue'
        ))

        dwg.save()
        print(f"Generated badge: {output_path}")

Got: Per-item graphic gen If err: Check data struct, defaults for missing

7. SVG → Raster

import cairosvg

def svg_to_png(svg_path, png_path, dpi=300):
    """Convert SVG to PNG with specified DPI."""
    # Calculate pixel dimensions from DPI
    # Assuming A4 size as example
    width_inches = 8.27
    height_inches = 11.69

    width_px = int(width_inches * dpi)
    height_px = int(height_inches * dpi)

    cairosvg.svg2png(
        url=svg_path,
        write_to=png_path,
        output_width=width_px,
        output_height=height_px
    )
    print(f"Converted to PNG: {png_path}")

def svg_to_pdf(svg_path, pdf_path):
    """Convert SVG to PDF."""
    cairosvg.svg2pdf(url=svg_path, write_to=pdf_path)
    print(f"Converted to PDF: {pdf_path}")

Got: Raster out @ res If err: Install cairo sys lib, check SVG valid

Check

• Graphics render in target apps
• Text readable + positioned
• Colors match (hex)
• Dims fit use case
• SVG validates (if req)
• Raster DPI correct
• Layout adapts to data
• Batch completes no err
• Out files organized
• Err handling in code

Traps

1. Unit confusion: SVG units (px, mm, cm) vs screen px vs print DPI
2. Text overflow: Text exceeds shape → wrap
3. Font avail: Sys fonts differ → embed / web-safe
4. Coord calc: Off-by-one in grids
5. Color fmt: SVG hex (#rrggbb), not tuples
6. SVG valid: XML struct, close tags
7. File paths: Special chars, spaces
8. Memory: Large batch → chunk
9. Aspect ratio: Preserve on resize
10. Transparency: PNG alpha, JPEG not

→

• render-publication-graphic: Publication out reqs
• create-3d-scene: 3D variant
• generate-quarto-report: Graphics in reports