I have three QGraphicsView s each one with a different scene.
I am trying to scroll all the views when the user is scrolling one of them.
The scrolling is carried out by the user dragging in the QGraphicsView widget which calls QGraphicsView::scrollContentsBy. (no scrollbars)
My first implementation:
From scrollContentsBy I am calling centerOn for all the other views but this ends up into a recursive call of scrollContentsBy.
My second implementation:
From scrollContentsBy I am calling scroll for all the other views but the view is not updated correctly (missing part of the scene). It does scroll correctly though.
I tried different versions on this but I can't find the solution.
Any idea would be great.
Edit:
I found the answer but I need to wait 3 more hours before to reply to my own question :)
I am glad that in fact I can answer my own question and share the answer with others.
The only thing that you have to do, it is to create 2 scrollbars (one vertical and one horizontal) and to set these two scrollbars for all the QGraphicsView instances. When the user drag one picture all the view receive the same event and scrollContentsBy is called for each view.
Easy when you know.
m_hScrollBar = new QScrollBar(Qt::Horizontal);
m_vScrollBar = new QScrollBar(Qt::Vertical);
m_srcView->setHorizontalScrollBar(m_hScrollBar);
m_srcView->setVerticalScrollBar(m_vScrollBar);
m_dstView->setHorizontalScrollBar(m_hScrollBar);
m_dstView->setVerticalScrollBar(m_vScrollBar);
m_diffView->setHorizontalScrollBar(m_hScrollBar);
m_diffView->setVerticalScrollBar(m_vScrollBar);
Related
I am using MVC for my project. And I have few views in View. However, I want to know how to add a scrollbar to one view and only make that part can be scrolled vertically.
I have tried using CreateWindowW() for adding WM_VSCROLL parameter, but it does not work.
This is a TUI application, so I think the professor try to make us using a cell as bar, so you can scroll the cell up and down
In PreCreateWindow(CREATESTRUCT& cs), set cs.style |= WS_VSCROLL;.
You may have to respond to WM_VSCROLL to process scroll messages.
Sorry for the confusing. I am resisted to use TUI only. And I misunderstood what the professor needed. So he wanted us to move a color cell so you can scroll up and down for checking player's moves. I am making a Gomoku Game by using C++. So I figure it out, right now my move list view can move up and down for viewing full moves. Thanks for all the answers
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I am programming a game and I have a tab widget which takes up the majority of the window. I want to use the extra space in the tab bar for buttons. I have the tab widget in a grid layout. To accomplish this, I use the code below in order to remove and add back the button widgets to the desired areas (the solution to someone else's question).
ui->centralLayout->removeWidget(ui->exitButton);
ui->centralLayout->removeWidget(ui->ResizeButton);
ui->centralLayout->addWidget(ui->ResizeButton,0,4, Qt::AlignTop|Qt::AlignRight);
ui->centralLayout->addWidget(ui->exitButton,0,4, Qt::AlignTop|Qt::AlignRight);
This does not work for me; however, because I would like the second widget-- the resize button-- to be just to the left of the exit button. What is occurring is that it instead overlaps the exit button. I simply need to move it 21 pixels to the left and have no idea how!
I tried putting both buttons in a frame and then removing and adding the frame the way I did the buttons. Unfortunately the same functions I used do not exist for the qt frame object.
Here are some pictures of my window.
https://docs.google.com/document/d/17w5USWQcCtb6OdcRShdcYcRjXTcdVpmdrG5TWLX71y8/edit?usp=sharing
you are using void QGridLayout::addWidget(QWidget * widget, int row, int column, Qt::Alignment alignment = 0) overload.
2-nd and 3-rd parameters are row and column of a grid. And you put 2 widgets in the same cell so they are overlaping each other.
I solved my problem. Earlier when I was trying to add them to a frame and reposition it I could not but using a widget as the container for my buttons let me place them the way I was earlier attempting to individually place the buttons.
I have a collection of images, dynamically generated through QGraphicsView widgets, and i'd like my users to choose between them. For that purpose, i would display inside a custom widget available images in some kind of grid and have users click the one they are interested in.
Multiple questions arise :
is there an existing widget that already fits this purpose ?
should i find a way to disable all mouse event handling by QGraphicsView items, or could i add a transparent widget in front of graphic views which would intercept them ?
is there a performance issue displaying many QGraphicsView widgets (up to a few hundreds) ? Should i export them to plain images first ?
First off, no, there's no widget designed specifically for that purpose.
I don't think you are grasping what QGraphicsView is for. It's for displaying a QGraphicsScene, which is meant to hold many QGraphicsItems. Based on your post, I can't see why you would need multiple QGraphicsViews. You can simply have one QGraphicsView and display many images inside of its scene. For example, see QGraphicsPixmapItem.
You definitely should not have hundreds of QGraphicsViews. You probably just want one (although a few could be justified in certain circumstances), in which you display many QGraphicsItems in a QGraphicsScene. You can definitely have hundreds of QGraphicsItems visible at once. In your case, you probably want QGraphicsPixmapItems, which are a subclass of QGraphicsItem. You could even have multiple QGraphicsScenes, and display whichever one is relevant using QGraphicsView::setScene. If you want the user to be able to select an image from a grid, and then work with that image, I would look to the State Pattern.
I can't think of any reason to disable mouse handling in QGraphicsViews, QGraphicsScenes, or QGraphicsItems. Why should these not handle their own mouse events? You can (and should, where necessary) subclass them and reimplement mousePressEvent, mouseMoveEvent, mouseRelease event, etc. to obtain the functionality you want.
Good luck!
Let's say that I have an application frame, and I want to show a popup QCalendarWidget over on the right side of the frame. Normally, QT will clip the edges of the QCalendarWidget, cutting it in half and not displaying the rest, as it would be over the right side border.
Is there a way to work around this limitation without resorting to implementing a QDialog?
I want the widget to be visible outside the bounds of it's container.
If you'd show your Calendar, let's say, after a button click, as QDateTimeEditor does, it's contents will not be clipped, cause it do not belong to frame. It will be just a widget, that shows in a dialog manner. And maybe you should even place it in QDialog, that is modal and provides some convenience methods, rather then simple QWidget.
Btw, why don't you want to use QDatetimeEditor?
I am trying to create an app in Qt/C++ with Qt4.5 and want the any active windows to change opacity on a mouseover event...
As i understand it, there is no explicit mouseover event in Qt.
However, I got rudimentary functioning by reimplementing QWidget's mousemoveevent() in the class that declares my mainwindow. But the mainwindow's mousemoveevent is not called whenever the mouse travels over any of the group boxes i have created in there (understandbly since QGroupbox has its own reimplementation of mousemoveevent).
So as a cheap work around, I am still using the mousemoveevent of my mainwindow but a query the global mouse position and based on the (x,y) position of the mainwindow (obtained through ->pos()) and the window size (-> size -> rHeight and rWidth), I check if the mouse is within the bounds of the area of the mainwindow and change the opacity thus.
This has had very limited success. The right border works fine, the the left changes opacity 4 pixels early. The top does not work (presumably because the mouse goes through the menubar and title bar) and the bottom changes way too early.
I thought of creating an empty container QWidget class and then place all the rest in there, but i felt that it would still not solve the big issue of the base widget not receiving the mousemoveevent if it has already been implemented in a child widget.
Please suggest any corrections/errors I have made in my method or any alternate methods to achieve this.
p.s. I doubt this matters, but I am working Qt Creator IDE, not Qt integration into VS2008 (it's the same classes anyways - different compiler though, mingw)
Installing event filters for each of your child widgets might do the trick. This will allow your main window to receive child events such as the ones from you group boxes. You can find example code here.
You may be interested in Event filters. QObject proves a way to intercept all events zipping around your application.
http://doc.trolltech.com/4.5/eventsandfilters.html#event-filters
If I understand what you are attempting to do, I would reimplement the widget's enterEvent() and leaveEvent(). The mouse enter event would trigger the fade-in and the leaveEvent would trigger the fade-out.
EDIT: After re-reading several times, I'm still not sure what you are trying to accomplish. Sorry if my suggestion doesn't help. :-)