Databases
StackOverflow2013
Postsdbo
POQGraphicsView rubber band selection rectangle not visible
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POQGraphicsView rubber band selection rectangle not visible
    primarykey
    data
    text
    <p>I have a <code>QGraphicsView</code> widget with lots of items on scene. I am panning the view on ctr+left mouse click and zooming it to rectangle of rubber band created with left mouse button drag. I am not able to see rubber band selection rectangle (dotted lines) whereas rubberband selection functionality works fine. Can anybody help me understand this?.<br>I use these flags in my view:</p> <pre><code>setTransformationAnchor(QGraphicsView::AnchorUnderMouse); setViewportUpdateMode(QGraphicsView::SmartViewportUpdate); setRenderHints(QPainter::HighQualityAntialiasing | QPainter::SmoothPixmapTransform); setOptimizationFlag(QGraphicsView::DontSavePainterState,true); setCacheMode(QGraphicsView::CacheBackground); setOptimizationFlag(QGraphicsView::DontAdjustForAntialiasing); setViewport(new QGLWidget); </code></pre> <p>below are my event handlers.</p> <p>Mouse press event handler:</p> <pre><code>void MyView::mousePressEvent(QMouseEvent* event) { if(event-&gt;button()==Qt::LeftButton) { if(event-&gt;modifiers()==Qt::ControlModifier) { setDragMode(QGraphicsView::NoDrag); m_rubberBandActive = false; mousepressed=true; m_lastDragPos = event-&gt;pos(); return; } else { setDragMode(QGraphicsView::RubberBandDrag); m_rubberBandOrigin = event-&gt;pos(); m_rubberBandActive = true; } } event-&gt;accept(); } else { QWidget::mousePressEvent(event); } } </code></pre> <p>Mouse move event:</p> <pre><code>void MyView::mouseMoveEvent(QMouseEvent* event) { if(mousepressed) { QPointF delta = mapToScene(event-&gt;pos()) - mapToScene(m_lastDragPos); this-&gt;panView(delta); m_lastDragPos = event-&gt;pos(); return; } event-&gt;accept(); } </code></pre> <p>Mouse release event Handler:</p> <pre><code>void MyView::mouseReleaseEvent(QMouseEvent *event) { if (m_rubberBandActive) { QPoint rubberBandEnd = event-&gt;pos(); QRectF zoomRectInScene = QRectF(mapToScene(m_rubberBandOrigin),mapToScene(rubberBandEnd)); fitInView(zoomRectInScene, Qt::KeepAspectRatio); m_rubberBandActive = false; } mousepressed=false; event-&gt;accept(); } </code></pre> <p>Pan view:</p> <pre><code>void MyView::panView(QPointF delta) { QPoint viewCenter(viewport()-&gt;width() / 2 + delta.x(), viewport()-&gt;height() / 2 + delta.y()); QPointF newCenter = mapToScene(viewCenter); centerOn(newCenter); } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USTRS
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. COI had problems like this, I ended up implementing my own ctrl+left button panning, and my own left button rubber band rect with auto scroll :(
      singulars
      1. POQGraphicsView rubber band selection rectangle not visible
      1. USpaulm
    2. COI got more convincing answer here.. http://www.qtcentre.org/threads/53944-QgraphicsView-rubber-band-selection-rectangle-not-visible?p=241615&highlight=#post241615
      singulars
      1. POQGraphicsView rubber band selection rectangle not visible
      1. USTRS
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload