how to delete a PrsDim_LengthDimension - Forum Open Cascade Technology

Daniel Duesentrieb
Sat, 03/08/2025 - 20:00

Forums:

Hello all,

how to delete a PrsDim_LengthDimension?

void OccBase::clearDimensions()
{
    qDebug() << "dimensions before cleaning" << m_dimensions.size();
    Handle(PrsDim_LengthDimension) dim;
    for (int i=0; i<m_dimensions.size(); i++)
    {
        dim = m_dimensions.at(i);

        OccViewManager::instance()->myContext()->Erase(dim, Standard_True);
        OccViewManager::instance()->myContext()->Remove(dim, Standard_True);
        OccViewManager::instance()->myContext()->Update(dim, Standard_True);
        dim->DimensionAspect().Nullify();
        dim.Nullify();
        Standard::Purge();
    }
    m_dimensions.clear();
    qDebug() << "dimensions after cleaning" << m_dimensions.size();
    OccViewManager::instance()->myContext()->UpdateCurrentViewer();
    OccViewManager::instance()->myContext()->CurrentViewer()->Redraw();
}

this only removes the text and the two lines to the points but not the long line between the points

Thanks!

gkv311 n
Mon, 03/10/2025 - 08:45

        OccViewManager::instance()->myContext()->Erase(dim, Standard_True);
        OccViewManager::instance()->myContext()->Remove(dim, Standard_True);
        OccViewManager::instance()->myContext()->Update(dim, Standard_True);
        dim->DimensionAspect().Nullify();
        dim.Nullify();
        Standard::Purge();

Here you need to call only OccViewManager::instance()->myContext()->Remove(dim, false), everything else is redundant and looks suspicious. Calling ::Update() for removed object certainly looks wrong.

AIS_InteractiveContext::Erase() hides presentation but keeps it in Context for fast redisplay, while AIS_InteractiveContext::Remove() completely removes it from Context (visual effect should be the same, the difference is either you want to redisplay object later or want to abandon it completely).

    OccViewManager::instance()->myContext()->UpdateCurrentViewer();
    OccViewManager::instance()->myContext()->CurrentViewer()->Redraw();

These two lines do (almost) the same thing, hence only one should be left (::UpdateCurrentViewer() for example). If you are using AIS_ViewController (preferred), then you better call AIS_ViewController::FlushViewEvents() instead.

Note that the last boolean flag in AIS_InteractiveContext::Remove()/::Erase()/::Display() methods is to update the viewer.\ You should pass FALSE there if you call AIS_InteractiveContext::UpdateCurrentViewer() afterwards, otherwise you are redrawing viewer redundantly multiple times.

gkv311 n
Mon, 03/10/2025 - 08:44

this only removes the text and the two lines to the points but not the long line between the points

If you experience some bug - it would be better providing a complete reproducer to see why it might happen.