Details
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Bug
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Resolution: Unresolved
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P3: Somewhat important
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None
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6.6.1
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None
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Linux/X11
Description
Under Linux custom cursors created with QDrag::setDragCursor are shown at a wrong position: The hotspot is always the center of the pixmap. The same call works well with Windows, where the hotspot is the top/left corner. Reason is, that QBasicDrag::updateCursor (qsimpledrag.cpp) creates the cursor with the default hotspot position, whereas QWindowsOleDropSource::createCursors (qwindowsdrag.cpp) calculates an exact hotspot position:
if (hasPixmap) {
const int x1 = qMin(-hotSpot.x(), 0);
const int x2 = qMax(scaledPixmap.width() - hotSpot.x(), cursorPixmap.width());
const int y1 = qMin(-hotSpot.y(), 0);
const int y2 = qMax(scaledPixmap.height() - hotSpot.y(), cursorPixmap.height());
QPixmap newCursor(x2 - x1 + 1, y2 - y1 + 1);
newCursor.fill(Qt::transparent);
QPainter p(&newCursor);
const QPoint pmDest = QPoint(qMax(0, -hotSpot.x()), qMax(0, -hotSpot.y()));
p.drawPixmap(pmDest, scaledPixmap);
p.drawPixmap(qMax(0, hotSpot.x()),qMax(0, hotSpot.y()), cursorPixmap);
newPixmap = newCursor;
newHotSpot = QPoint(qMax(0, hotSpot.x()), qMax(0, hotSpot.y()));
}
In order to give the user full control over the position of the hotspot, I suggest to add a further function to QDrag:
QDrag::setDragCursor(const QCursor &cursor, Qt::DropAction action)
(but in that case QCursor should support negative hotspot coordinates)