Print-Scale Exporter for Aseprite

Created by MrSmithr

This Aseprite extension allows you to export pixel art at real-world print scale  with accurate DPI (dots per inch) metadata embedded directly into the PNG file. Ideal for artists preparing artwork for high-resolution printing, packaging, or physical media.

 Features

•  Set real-world scale in centimetres per pixel

• Choose from common DPI presets (72, 150, 300, 600)

•  Automatically calculates scaled image dimensions

•  Embeds DPI metadata (via PNG pHYs chunk)

•  Prompts for export location and confirms overwrites

•  Optionally opens the containing folder after export

•  Cross-platform folder reveal (Windows, Linux, macOS)

 How to Use

1. Open any sprite in Aseprite.

2. Run the Print-Scale Exporter script from File → Scripts.

3. Set the real-world size of a pixel (e.g. 1.00 cm).

4. Choose a DPI preset (300 is typical for print).

5. Click "Scale and Save Copy".

6. Choose where to save the final image.

7. If enabled, your file explorer will open the folder after export.

The exported PNG will contain the correct DPI metadata, allowing most image editors and printers to interpret its print dimensions accurately.

Technical Notes

• The script uses a custom Lua PNG parser (pnglib) to insert the pHYs chunk manually.

• The temporary file is safely cleaned up after export.

• Output image size is capped at 8192×8192px to prevent Aseprite crashes or system instability.

Licence

Licensed under the Apache License 2.0
You may share and modify this script. Please credit MrSmithr and clearly document any changes you make.