Three bugs were causing a crash (SIGSEGV in QRegion::begin) when
a power NC slave element was placed on a folio, even before linking
it to a master element.
1. m_drawing (QPicture) was never reset between updateLabel() calls.
QPicture accumulates paint commands — calling qp.begin() on an
existing QPicture appends to it rather than replacing its content.
After several updates (load, move, hover...) the picture became
corrupted and crashed on play().
Fix: reset m_drawing = QPicture() at the start of updateLabel().
2. m_drawed_contacts was only initialized to 0 in drawAsContacts(),
but not in drawAsCross(). When drawing in Cross mode, fillCrossRef()
called drawContact() with an uninitialized m_drawed_contacts value,
producing a garbage offset. The NC contact symbol uses drawPolyline()
with a sub-pixel Y coordinate (offset+2.5); with a random offset Qt
generated an invalid QRegion and crashed.
This explains why NC contacts crashed but NO contacts did not: the
NO symbol only uses drawLine() which is more tolerant of bad coords.
Fix: add m_drawed_contacts = 0 at the start of drawAsCross().
3. setUpCrossBoundingRect() used QRectF() (null rect) as the reference
rect for painter.boundingRect(), which can return invalid dimensions.
Additionally, height was accumulated incorrectly: united() + setHeight()
doubled the height at each iteration, causing an exponentially growing
bounding rect with multiple contacts.
Fix: use QRectF(0, 0, 500, 20) as reference rect and accumulate
height and width independently.
Laurent Trinques
d949e6eb8c