Tobias KlausmannandDominic Radermacher 921206cd5f print_img: correct off-center print area via per-device pin_offset ...

On the PT-P900W the print area is not centered on the 560-pin printhead:
its center sits at pin 272 rather than the head center (pin 280), a fixed
8-pin offset that is constant across all tape widths. Centering the raster
data on the head therefore prints ~0.5mm off-center (measured as a constant
~1mm margin delta across 12/18/36mm tapes, confirmed against the spec).

Add a pin_offset field to _pt_dev_info (0 = centered, the default for all
existing printers) and apply it in print_img. Set it to -8 for the
PT-P900Wc, which reproduces the spec left-margin exactly for every tape
width ((560-print_area)/2 - 8 = documented left margin).

Reference: Brother "Software Developer's Manual - Raster Command Reference,
PT-P900/P900W/P950NW", section 2.3.5 "Raster line" (per-tape left/right
margin and print-area pin counts for the 560-pin head).
https://download.brother.com/welcome/docp100407/cv_ptp900_eng_raster_102.pdf

2026-07-18 08:01:24 +02:00

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ptouch.h

print_img: correct off-center print area via per-device pin_offset

2026-07-18 08:01:24 +02:00