Fix a use-after-free crash (SIGSEGV in QRegion::begin, Qt5Gui+0x49af60)
confirmed by analysis of 19 coredumps. The crash was triggered when the
scene viewport clip region was freed during zoom/resize events while
QPicture::play() replayed drawPolyline commands through the scene painter.
Qt's raster engine then dereferenced a stale QRegionData pointer.
Root cause: CrossRefItem used three nested QPicture objects (m_drawing,
m_hdr_no_ctc, m_hdr_nc_ctc). The nested drawPicture() calls amplified
the use-after-free risk on any repaint event.
Fix: remove all QPicture from CrossRefItem entirely.
- updateLabel() now uses a QImage-backed dummy painter to compute
m_bounding_rect, m_shape_path and m_hovered_contacts_map geometry.
A bool m_update_map flag prevents the map from being overwritten
during paint().
- paint() calls drawAsCross()/drawAsContacts() directly on the scene
painter — no QPicture::play() anywhere in the class.
- buildHeaderContact() now draws NO/NC symbols directly onto the painter
instead of recording them into QPicture members.
Also fix mouseDoubleClickEvent: the element under the click is now found
directly from m_hovered_contacts_map using the event position, rather
than relying on m_hovered_contact which could be reset by hoverMoveEvent
between the two clicks of a double-click.
Also remove setBold(true) on terminal name labels: the Qt PDF/SVG/print
engine rendered bold at 4pt as extremely thick glyphs, making exports
unreadable. Normal weight at 4pt is correct and legible on all backends.
Fixes: SIGSEGV in CrossRefItem::paint() on zoom/resize
Fixes: double-click navigation unreliable on Xref contact symbols
Fixes: terminal name labels unreadable in PDF/SVG/print export
Laurent Trinques
6dd7c2d926