`.drawio.png` file saving generates invalid/broken blank image

[saiya]

Hi! Thank you for making super great plugin.

I would like to report an issue of the latest this plugin + latest InteliJ IDEA.

My environment

• MacOS 14.7.2
• InteliJ IDEA 2024.3.1 CE
• Diagrams.net Integration 0.2.6

Problem

1. Create empty .drawio.png file, or open .drawio.png file with this plugin
2. Edit the image
3. Save
4. Open the file with any image viewer (InteliJ's image viewer, Mac's Preview.app, browser, ...) that shows blank

The mimimal reproduced example

Edit with this plugin:

Open that drawio.png with any viewer:

The file (compressed as zip to prevent GitHub doing any post-processing): test.drawio.png.zip

Workaround

Editing and saving that image with draw.io's official standalone editor works well.
The resulted .drawio.png image is valid PNG.

Note: Because editing that image with the draw.io's official standalone editor works well, embedding draw.io metadata inside PNG looks working well.

[saiya]

I don't remember exact version, but the .drawio.png editing worked well until very recent version (likely previous version of InteliJ)