Export SVG to EMF using CLI ( Increase resolution almost 10x )

Summary: Inkscape CLI incorrectly scales up the resolution and DPI when exporting an SVG file to EMF format. The exported EMF file has a significantly higher resolution and DPI than the original SVG, resulting in unintended scaling.

Steps to Reproduce:

1. Create an SVG file with a simple geometric shape.
2. Export the SVG to EMF using Inkscape's CLI: inkscape sample_diagram.svg --export-type=emf --export-dpi=90 --export-filename=sample_diagram.emf
3. Check the resolution of the resulting EMF file.

What happened?

• The EMF file was saved with a much higher resolution than expected.
• The DPI of the EMF file was far greater than the specified --export-dpi=90 setting.
• The resolution increased drastically (e.g., SVG: 347x347 units → EMF: 5810x5810 pixels at ~1200 DPI).

What should have happened?

• The exported EMF file should retain the same dimensions and proportions as the original SVG.
• The resolution and DPI should respect the --export-dpi flag without unexpected scaling.

Sample attachments:

• sample_diagram.svg
• sample_diagram.emf sample_diagram.emf(exported EMF file showing the issue)
• Terminal output/logs:

SVG file saved: sample_diagram.svg
EMF file saved: sample_diagram.emf
SVG Resolution: 347.04 x 347.04 units
EMF Resolution: 5810 x 5810 pixels at 1199.8861696072852 DPI

Version info:

# Run 'inkscape --debug-info' and paste output here
Inkscape 1.4
OS: macOS 15.3.2
Installation method: Official package from inkscape.org

Python Based Code:

import matplotlib.pyplot as plt
import subprocess
import os
import xml.etree.ElementTree as ET
from PIL import Image

def get_svg_resolution(svg_file):
    """Extracts viewBox width and height from the SVG file."""
    try:
        tree = ET.parse(svg_file)
        root = tree.getroot()
        width = root.get("width")
        height = root.get("height")
        viewBox = root.get("viewBox")

        if viewBox:
            viewBox_values = list(map(float, viewBox.split()))
            width = viewBox_values[2]
            height = viewBox_values[3]
        
        print(f"SVG Resolution: {width} x {height} units")
    except Exception as e:
        print(f"Error extracting SVG resolution: {e}")


def get_emf_resolution(emf_file):
    try:
        
        with Image.open(emf_file) as img:
            dpi = img.info.get("dpi", "Resolution info not available")
            print(f"EMF Resolution: {img.width} x {img.height} pixels at {dpi} DPI")
    except Exception as e:
        print(f"Error reading EMF resolution: {e}")


def generate_svg(output_svg):
    """Generates a sample geometric plot and saves it as an SVG file."""
    fig, ax = plt.subplots(figsize=(6, 6), dpi=300)  # High-resolution figure

    # Draw some geometric shapes
    circle = plt.Circle((0.5, 0.5), 0.3, color='blue', fill=False, linewidth=2)
    rect = plt.Rectangle((0.2, 0.2), 0.4, 0.3, color='red', fill=False, linewidth=2)
    
    ax.add_patch(circle)
    ax.add_patch(rect)
    
    ax.set_xlim(0, 1)
    ax.set_ylim(0, 1)
    ax.set_aspect('equal')
    ax.axis('off')

    fig.savefig(output_svg, format='svg', bbox_inches='tight', dpi=300)
    print(f"SVG file saved: {output_svg}")

def convert_svg_to_emf(input_svg, output_emf):
    """Converts an SVG file to an EMF file using Inkscape."""
    inkscape_path = "/Applications/Inkscape.app/Contents/MacOS/inkscape"  # macOS path
    # inkscape_path = "C:\\Program Files\\Inkscape\\bin\\inkscape.exe"  # Windows path

    try:
        subprocess.run([
            inkscape_path, 
            "--export-type=emf", 
            "--export-dpi=90",  # Set DPI
            "--export-filename", output_emf, 
            input_svg
        ], check=True)
        print(f"EMF file saved: {output_emf}")
    except subprocess.CalledProcessError as e:
        print(f"Error converting SVG to EMF: {e}")

# Define file paths
output_svg = "sample_diagram.svg"
output_emf = "sample_diagram.emf"

# Run the functions
generate_svg(output_svg)
convert_svg_to_emf(output_svg, output_emf)

# Get and print resolutions
get_svg_resolution(output_svg)
get_emf_resolution(output_emf)