For memory- and time-efficient manipulation, a simple binary data structure is used to represent the cell data for one slide.
The memory map is as follows:
| Byte range start | Byte range end | Number of bytes | Section | Description | Data type |
|---|---|---|---|---|---|
| 1 | 4 | 4 | Header | The number of cells represented by this serialization. | 32-bit integer, big-endian byte order |
| 5 | 8 | 4 | Minimum first pixel coordinate occurring in this file. | 32-bit integer, big-endian byte order | |
| 9 | 12 | 4 | Maximum first pixel coordinate occurring in this file. | 32-bit integer, big-endian byte order | |
| 13 | 16 | 4 | Minimum second pixel coordinate occurring in this file. | 32-bit integer, big-endian byte order | |
| 17 | 20 | 4 | Maximum second pixel coordinate occurring in this file. | 32-bit integer, big-endian byte order | |
| 21 | 24 | 4 | Cell 1 | Cell 1 index integer. | 32-bit integer, big-endian byte order |
| 25 | 28 | 4 | Cell 1 location's first pixel coordinate integer. | 32-bit integer, big-endian byte order | |
| 29 | 32 | 4 | Cell 1 location's second pixel coordinate integer. | 32-bit integer, big-endian byte order | |
| 33 | 40 | 8 | Cell 1 phenotype membership bit-mask, up to 64 channels. | 64-bit mask | |
| 41 | 44 | 4 | Cell 2 | Cell 2 location's first pixel coordinate integer. | 32-bit integer, big-endian byte order |
| ... | ... | ... | ... | ... |
The ellipsis represents repetition of the per-cell section once for each cell. This is 4 + 4 + 4 + 8 = 20 bytes per cell. The "header" preceding the per-cell sections is 20 bytes.
A representation of an example of the cell sections can be found here.
There is a convenient way to preview the contents at the command line using xxd:
tail -c +21 payload.bin | xxd -b -c 20(The initial tail command strips out the header.)