@mrjj Yes, it worked. Thank you!

It appears that QGraphicsScene checks if position of item is visible in view and then draws/dont draws it... returning qgraphicsScene->sceneRect() as boundingRect on my curve "solved" the issues but its a problem for selectable items... hmmm

Hi,

Can you provide a minimal compilable code that shows that behaviour ?

@sgaist Hmmmmmmmmm I wrote a little routine to use mouse press/release to see what has changed to determine my selection but it does not work as well as I wish. But I missed that focusItemChanged mhmhmhmh thanks! Will go over it again :- )

I have just figured it out.

My first misunderstanding was that the boundingRect()'s coordinates must be (-0.5,-0.5) which means they are relative to the current item's position and not absolute on the Scene. and so this is the correct one:

QRectF GIPoint::boundingRect() const { // return QRectF(pos().x(), pos().y(), 5, 5); return QRectF(-0.5, -0.5, 5, 5); }

My second misunderstanding was in paint(). Do not use the pos() or scenePos() coordinates in order to draw the item. Instead draw it at (0,0). So the corrected paint() is this:

void GIPoint::paint( QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget ){ (void )option; (void )widget; QRectF rect = boundingRect(); qWarning() << "painting: scenePos " << scenePos() << ", rect " << rect; QBrush brush = QBrush(Qt::black, Qt::SolidPattern); painter->fillRect(rect, brush); //painter->drawRect(rect); }

The original program in my question still needs to be modified. Or shall I edit the changes in?

Scale_5.gif
可以参考这个网站进行进行背景图的绘制，缩放的原理 等https://www.desmos.com/calculator?lang=zh-CN
同时参考这这个链接，进行背景绘制https://stackoverflow.com/questions/24728477/infinite-grid-in-qt

Call fitInView on the GraphicsView with the Image whenever the size of the GraphicsView changes. The rest should work automatically.

Hi,
I got the expected output from grab(QRect)
https://stackoverflow.com/questions/16362191/qt-grab-widget-and-save-image

m_graphicsView->grab(rect).save("OUT.jpg");

Thanks all.

Thanks @SGaist and @raven-worx , I try both methods to see which one to use better in my program.

I found the problem. I was drawing the beats before the lines, so the lines took precedent over the beats since they are siblings. The solution was to either draw the beats last or set the Z value on the beat, not the note.

The idea is that you have your container widget getting resized and in its resize event, you change the size of the inner widgets with the ratio you want.

@Niagarer
Good found. :)

@mrjj There are other obstacles that I need to overcome. But this way seems to be the solution that i am implementing.
Thanks

@SGaist

Hi Sam,

Thank you for your hint, but my first problem was preventing the edit trigger on single click.

For the posterity I have ended up with the following solution:

Disable the textInteraction flags by default Override the QGraphicsTextItem::sceneEvent with the following: bool ValueAxisLabel::sceneEvent(QEvent *event) { if (event->type() == QEvent::GraphicsSceneMouseDoubleClick) { setTextInteractionFlags(Qt::TextEditorInteraction); bool ret = QGraphicsTextItem::sceneEvent(event); // QGraphicsTextItem::sceneevent needs to be processed before // the focus setFocus(Qt::MouseFocusReason); return ret; } return QGraphicsTextItem::sceneEvent(event); }

The textInteractionFlags should be disabled in the overridden focusOutEvent.

@Buckwheat How do you avoid panning and transform ( Zoom ) for those site scale and compass rose ?

Found the solution: Use painter.resetTransform().

@AdrianCruz
hi
Super :)
just as a note
To avoid getting possible NULLs in the list, i would suggest doing

QGraphicsItem *item = qgraphicsitem_cast<QGraphicsItem*>(text); if (item) list.push_back(item);

Hi,

You shouldn't use the size of a widget in its own constructor. The widget being not yet visible, the value won't make sense.