PNG Palette and Priority Editor for SGDK

PPP Editor for SGDK is a Java-based tool for editing palette and priority masks on indexed 8bpp PNG images, specifically designed for SGDK (Sega Genesis Development Kit) projects.

With PPP Editor, you can:

✅ Load and visualize indexed 8bpp PNG images.
✅ Edit palette indices (0-3) and priority flags (0/1) on an 8×8 tile grid.
✅ Save this tile grid as a "mask" for future use
✅ Export the final image with the applied mask (=palette and priority encoding).
✅ Use a batch mode for automated processing via the command line.

Known issues

The tool is rather slow with bigger image... got to improve this indeed ! PNG above 1024x1024 tends to be laggy...and higher resolution may become unusable.

Installation & Usage

Need Java 8 (compiled with jdk1.8.0_441)

GUI Mode :

Download PPPE4SGDK.jar
To show the GUI , simply run with Java: "java -jar PPPE4SGDK.jar"

🏭 Batch Mode (Command Line Processing)

Run the editor via the command line for automated processing:
java -jar PPPE4SGDK.jar --b <image_path> <mask_path> <export_path>

Example:
java -jar PPPE4SGDK.jar --b bgb.png mask.msk bgb_palprio.png

Screenshots

Features :

🎨 Image & Mask Handling
Load indexed 8bpp PNG images.
Save and load .msk mask files to preserve tile properties.

🖱️ Editing Capabilities
Left Click & Drag → Lasso selection of multiple tiles.
CTRL + Left Click → Add/remove multiple selection areas.
Right Click → Open a property editor to modify Palette index (0-3) and Priority (0 = low, 1 = high)

Keyboard Shortcuts:
H → Set priority High (1)
L → Set priority Low (0)
0, 1, 2, 3 → Change palette index of selected tiles
SHIFT + Mouse Wheel → zooming
Arrow Keys → Scroll image
CTRL+Z / CTRL+Y → undo / redo

License

This project is open-source under the MIT License.