Xref paths saved in a drawing (on open, on Reload, in the External
References list, XOPEN, nested xrefs) and table data-link paths re-read by
DATALINKUPDATE go through doc_path::resolve (craft-docpath): relative
paths resolve beside the drawing that stores them, and paths to other
computers, devices and URLs are not opened. Such an xref is Unresolved
with the reason, unless a file of its name is beside the host drawing.
Paths given to XATTACH, -XREF Path and DATALINK are used as given.
One load of xrefs reads at most 1 GB from referenced files in total.
A colour or freeze set in the host on an xref's layers (xref|layer) was lost on save:
the saved view dropped every xref-dependent symbol, layers included, and the DWG save goes
through the same DXF tags. The reader already keeps such layers when the xref loads.
The xref's layers are now written as xref-dependent LAYER records (DXF Reference, LAYER
group 70: 16 externally dependent, 32 resolved), as AutoCAD does with VISRETAIN = 1, with
the xref linetypes they use (same flags): without them a DWG falls back to Continuous.
Co-authored-by: Brandon Thomas <echelon@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>