Converting JPG images to the C2P format is a specialized process used primarily by students, educators, and engineers who work with advanced graphing calculators. Specifically, the .c2p file extension is a proprietary picture format for the Casio ClassPad II (fx-CP400) Go to product viewer dialog for this item. graphic calculator.
4. Conversion Algorithm
4.1 Step-by-Step Process
- Read JPG – Use a JPEG library (libjpeg, stb_image) to decode to RGB.
- Convert to RGB – Ensure linear RGB representation.
- Quantize colors – Choose number of colors (C2P palette size).
Kalkimg (Open Source): A popular, free alternative available on GitHub that works without restrictive official passwords.
- Chunky vs. Planar:
The fundamental difference between a standard JPG and a C2P-compliant file lies in metadata integrity. A traditional JPG is "flat"; while it contains basic EXIF data like camera settings or GPS coordinates, this information is easily stripped or edited. In contrast, converting or capturing an image in a C2P framework attaches a secure, cryptographic "manifest." This manifest acts as a digital passport, recording the image’s entire journey—from the moment the shutter clicked to any subsequent edits made in software like Photoshop.
Because the .c2p format is proprietary and includes specific compression, you cannot simply rename a .jpg file; you must use a converter. ClassPad Ending Screens - Charlie Watson
- Retro graphics toolchains (Amiga, C64 asset converters) often include chunky-to-planar converters. Search for “chunky2planar”, “C2P converter Amiga”, “png to c2p” for ready-made tools.
- Emulator or game dev communities: sprite converters, tile editors (e.g., GrafX2, Tile Layer Pro, Aseprite with export scripts) may export planar formats or provide plugins.
Alternative Format: .c2b files are related and contain animations consisting of multiple C2P images. Available Conversion Tools
- Chunky vs. Planar: