ProbeFlow's Createc image reader is designed to preserve raw-file provenance while returning display-safe scan arrays for analysis.
Createc image .dat files contain a text header followed by a DATA marker and
a zlib-compressed little-endian float32 payload. In a hex or text viewer this
often appears as DATAx, because the first zlib byte is commonly 0x78
(x).
The reader now accepts only a DATA candidate that can be decompressed as zlib
from the byte immediately after the four marker bytes. This prevents header
comments or metadata values containing the word DATA from being mistaken for
the binary payload boundary.
Createc headers use simple key=value lines. Some lines can contain both an
internal and display name:
InternalName / DisplayName=value
ProbeFlow stores the display key and also keeps the internal key as an alias.
This keeps exact lookups such as Channels distinct from ScanChannels, while
still allowing old and new Createc header spellings to be read.
Some Createc files spell Angstrom with the Latin-1 Å byte. Known Dacto aliases
such as Dacto[Å]z are normalized to Dacto[A]z for calibration lookup.
CreatecDatDecodeReport.decoded_channels_dac is the canonical array field. It
contains decoded DAC values after ProbeFlow's safety cleanup:
- the zlib payload is decoded as little-endian
float32; - only the complete declared channel stack is reshaped;
- trailing non-image payload floats are ignored and recorded;
- incomplete rows are trimmed when explicit or heuristic evidence indicates a partial scan;
- the first stored column is removed by default.
Every healthy real Createc image fixture carries a small appendix after the
image planes: four spare scan-line buffers (4 * Num.X floats), plus a
32-float zero block in files with the newer header variant. The buffers are
zero-filled apart from an occasional stray sample at the start — the
turnaround point of a line that was never scanned. The appendix size does not
scale with the channel count (10- and 40-channel fixtures carry the same
4 * Num.X + 32 floats as 4-channel ones).
Because this appendix is normal format layout rather than data loss, the
reader records its size in ignored_tail_float_count but does not emit a
warning for tails within the 4 * Num.X + 32 budget. Tails larger than that
budget indicate payload the reader does not understand and still produce a
decode warning, which load paths surface to users.
The historical raw_channels_dac property remains as a compatibility alias, but
it points to the same cleaned decoded arrays. Use original_header,
original_Nx, and original_Ny when the acquisition dimensions or raw header
matter.
Real Createc image fixtures show a strong scan-line-start artifact in the first
stored column. ProbeFlow removes that column from every decoded plane by
default, then updates the decoded Num.X header value to match the returned
arrays.
This behavior is intentional. It prevents the artificial vertical column from reappearing in the browser, processing tools, exported images, and conversions. The original dimensions remain available on the decode report for diagnostics.
When ImageYPosMax is present, complete real fixtures record it as Num.Y + 1.
ProbeFlow interprets it as the one-based next Y position, so completed rows are
ImageYPosMax - 1. If that value is inside the declared image height, the scan
is marked partial and decoded arrays are trimmed to the completed rows.
If ImageYPosMax is absent or outside the declared height, ProbeFlow falls back
to the existing channel-0 row heuristic. is_partial_scan, image_y_pos_max,
original_Ny, and trimmed_Ny are recorded in the decode report so callers can
distinguish a completed smaller image from an interrupted acquisition.