The new binarized G-code file consists of a file header followed by an ordered succession of blocks, in the following sequence:
- File Header
- File Metadata Block (optional)
- Printer Metadata Block
- Thumbnails Blocks (optional)
- Print Metadata Block
- Slicer Metadata Block
- G-code Blocks
All of the multi-byte integers are encoded in little-endian byte ordering.
The file header contains the following data:
| type | size | description | |
|---|---|---|---|
| Magic Number | uint32_t | 4 bytes | GCDE |
| Version | uint32_t | 4 bytes | Version of the G-code binarization |
| Checksum type | uint16_t | 2 bytes | Algorithm used for checksum |
The size in bytes of the file header is 10.
Current value for Version is 1
Possible values for Checksum type are:
0 = None
1 = CRC32
All blocks have the following structure:
The block header is the same for all blocks. It is defined as:
| type | size | description | |
|---|---|---|---|
| Type | uint16_t | 2 bytes | Block type |
| Compression | uint16_t | 2 bytes | Compression algorithm |
| Uncompressed size | uint32_t | 4 bytes | Size of the data when uncompressed |
| Compressed size | uint32_t | 4 bytes | Size of the data when compressed |
The size in bytes of the block header is 8 when Compression = 0 and 12 in all other cases.
Possible values for Type are:
0 = File Metadata Block
1 = GCode Block
2 = Slicer Metadata Block
3 = Printer Metadata Block
4 = Print Metadata Block
5 = Thumbnail Block
Possible values for Compression are:
0 = No compression
1 = Deflate algorithm
2 = Heatshrink algorithm with window size 11 and lookahead size 4
3 = Heatshrink algorithm with window size 12 and lookahead size 4
Block parameters are used to let readers be able to interpret the block data.
Each block type may define its own parameters, so the size in bytes may vary.
Block data content is described by the block paramenters.
The size in bytes of the block data is defined in the block header.
For Compression = 0 it is Uncompressed size, otherwise it is Compressed size.
Block checksum is present when the Checksum type in the file header is different from 0.
The size in bytes depends on the selected algorithm. For CRC32 it is 4.
Table of key-value pairs of generic metadata, such as producer (software), etc.
| type | size | description | |
|---|---|---|---|
| Encoding | uint16_t | 2 bytes | Encoding type |
Possible values for Encoding are:
0 = INI encoding
Table of key-value pairs of metadata consumed by printer, such as printer model, nozzle diameter etc.
| type | size | description | |
|---|---|---|---|
| Encoding | uint16_t | 2 bytes | Encoding type |
Possible values for Encoding are:
0 = INI encoding
Image data for thumbnail. Each thumbnail is defined in its own block.
| type | size | description | |
|---|---|---|---|
| Format | uint16_t | 2 bytes | Image format |
| Width | uint16_t | 2 bytes | Image width |
| Height | uint16_t | 2 bytes | Image height |
Possible values for Format are:
0 = PNG format
1 = JPG format
2 = QOI format
Table of key-value pairs of print metadata, such as print time or material consumed, etc.
| type | size | description | |
|---|---|---|---|
| Encoding | uint16_t | 2 bytes | Encoding type |
Possible values for Encoding are:
0 = INI encoding
Table of key-value pairs of metadata produced and consumed by the software generating the G-code file.
| type | size | description | |
|---|---|---|---|
| Encoding | uint16_t | 2 bytes | Encoding type |
Possible values for Encoding are:
0 = INI encoding
G-code data.
| type | size | description | |
|---|---|---|---|
| Encoding | uint16_t | 2 bytes | Encoding type |
Possible values for Encoding are:
0 = No encoding
1 = MeatPack algorithm
2 = MeatPack algorithm modified to keep comment lines