I am using Ubuntu OS.
I am new to GTKMM GUI building application.
I am following the tutorials which they have on their websites.
https://developer.gnome.org/gtkmm-tutorial/stable/sec-helloworld.html.en
I can resize the window with helloworld.set_default_size(500,500);
but I cannot move the position of button("hello world").
It is always aligned at center.
I tried with m_button.set_alignment(0.0,0.0) but nothing seems to be working.
Why it is that much difficult to move button to any position.?
kindly suggest some solution if available.
If you want to place a widget like a button, you have to use some container widget like Gtk::Boxor Gtk::Grid. Inside such container widgets you can place you child widget as you like, but typically not directly per point position.
The container widgets use some internal logic to order and resize the contained widgets.
From the documentation:
Many GUI toolkits require you to precisely place widgets in a window, using absolute positioning, often using a visual editor. This leads to several problems: ...
gtkmm uses the packing system to solve these problems.
You can find the full documentation here:
Multi-item widgets
I did not know if there is a container widget which allows direct positioning by giving a point position. If someone has an additional hint, let us know!
Sometimes automatic is better than manual handling, but sometimes it is not :-)
Related
I want to resize everything when i show it in full screen automatically keeping aspect ratio. How can i do it. i use PyQt4 but if you know of C++ then also please tell me.
Hope the code will be not more than 2-3 lines.
Thanks
I suppose you've implemented static layouts with fixed widget sizes and positions in your dialogs/windows. In order to resize the widgets with the window, what you need to do is using dynamic layouts. You best use Qt Designer for the dialog design, else setting up any non-trivial layout can get rather toilsome.
I'm developing an application with C++ and GTK3 but I'm stucked. I've created a visual application with glade which has three columns and one of them, the middle one, is a DrawingArea. In that DrawingArea I want to draw some circles at the point I want to after pressing a button and have different mouse events on that circles (like drag and drop, double click, right click...). I've made the first thing (draw a circle after pressing a button) following the official documentation, but the problem is that I don't know how to do the mouse events, but I thought about it and I have some different solutions (I don't know if they are the bests solutions or maybe there are better):
I think the best way is to create a signal to the cairomm context, but I didn't see anything to do that. Maybe the way would be to create a cairo surface or something like that.
Every time I click to create a circle, I would have to create a gtk widget in which I can handle mouse events. The problem here is that the widget needs to have circular shape and need to be drawable. Is it possible to create a circular DrawingArea? It could be the best. I saw the way to create custom widgets here.
Use goocanvasmm. The problem here is that goocanvasmm has a little documentation (I'm sorry I can not post more than two links because of my reputation) and I think this is not the best solution, I prefer to use cairomm.
This application was written in C using GTK2, and the circles were drawn using gnomecanvas, adding signals in an easy way to each circle; and now I'm moving this application to C++ and GTK3 to renew it.
I'm very new to GTK (and graphical interfaces in general), but I looked for solutions for hours and I don't know what is the best way in order to continue my work.
Thank you for your help :)
It's best to use a canvas library for this such as GooCanvas. Doing it with cairo alone would require you to listen to mouse events on the whole drawing area, and keep track of where the circles were in order to decide which circle the mouse event belongs to - exactly the problem which the canvas library has already solved for you.
If you are having trouble with goocanvasmm documentation, a look at the documentation for GooCanvas' C API combined with knowledge of how the C API translates into C++ will usually suffice. Although the GooCanvasmm documentation seems fairly extensive to me.
I'm having all sorts of size problems with Qt. I am creating my own widgets and using different layouts (generally, I need my own to make them work properly without spending hours on the "powerful" default layouts... which don't lay things out as intended.)
Once I'm done with a widget and its layout though, it doesn't work right. The size is never getting set properly unless I call widget->resize(1, 1); which finally forces a "resize" and makes the widget look correct (i.e. recompute the geometry.) Even the updateGeometry() call has no effect.
This is a dreadful problem when the resize() needs to be called on the parent widget (yuck!) and from what I'm reading should not be necessary were the layouts properly programmed.
Is there a sample that works and is not several thousand of lines long, or does Qt require several thousand lines to make anything work perfectly, even the simplest widget?
What are the minimal functions to be called to make a widget & its layout work at once?
Thank you.
Alexis
P.S. I tried to implement the sizeHint(), minimumSize(), maximumSize(), others that I'm missing? I was hoping that would be enough. Obviously, I also implement the setGeometry() on the layout to resize the children appropriately.
--- addition 1
There is a sample image with a layout that clearly isn't available as is in Qt. The positioning, functions, and colors of the different keys is XML driven and works for any keyboard in the world.
(note, this sample doesn't show the Enter key displayed on two rows and wider below than at the top; more or less, not doable at all with the regular layouts; of course, it works with my version.)
--- clarification
I'm not too sure how to describe the problem better. I was thinking to write a test widget next to see how I can reproduce the problem and then post that and eventually fix it. 8-)
The default layout function that the internal Qt layouts make use of require a lot of coding. I would like to avoid having to copy/paste all of that because for maintenance, it makes it close to impossible.
--- today's findings
As I needed to tweak one of the widgets, I decided to add a VBoxLayout and make it work.
I actually found the problem... One of the widgets in my tree is a QScrollArea and that sizeHint() returns (-1, -1). Not exactly what I'd expect but... whatever you put inside that widget has better know how to compute its width and height or else... it fails.
Looking at the code closely, I could actually compute the width by using the widest width found. Once I used that, the widget would appear (and it actually resizes itself as things change in the list, kinda cool.)
This being said, my earlier comment about having a tree of widgets that auto-resize themselves stands. From the root up to the parents of the leaves in your tree, all of those widgets will need a valid layout. Once I added one in the top widget it resized itself and its children properly (well... in my case up to the QScrollArea, the rest required a bottom to top resizing. Funny how that works!)
--- ah! ha! moment (or: what you find reading the implementation code!)
Today I bumped in another problem which just needed the correct call... I just couldn't find anything worth it in the documentation.
All the objects have a layout now, but a certain parent would not resize properly. Plain simple.
I had a call to the parent as following:
// changes to the children are changing the geometry
parentWidget()->updateGeometry();
Yeah. The docs says that's what you have to do. Nothing happens at all with that call. No idea what it's supposed to do, I did not look at that function. It never did anything for me anyway.
So... I looked at the layout to try to understand how it would send the info up/down. I did not see much except for one interesting comment:
// will trigger resize
This is said of the SetFixedSize mode. To reach that function you need to make the layout for update. Ah! Yes... the layout, not the parent widget... let's try that instead:
parentWidget()->layout()->update();
And voila! It resizes correctly in all cases I have. Quite incredible that the widget updateGeometry() doesn't trigger the same effect...
Although it's possible to do what you want it sounds like the problems you are having are because you're using Qt in a way that it's not meant to be used. Why do you need separate widgets for each key represented on the keyboard?
I see two options, both of which are better in some way:
Use QGraphicsScene and QGraphicsView.
A single custom widget that uses custom drawing to display the keyboard (and likely uses hover for hints).
The first option is probably better. Your keys could then be represented by QGraphicsSimpleTextItem's or even a QGraphicsSvgItem. It also provides a number of standard layouts or you could choose to write your own layout. By default you can use the keyPressEvent or mouseReleaseEvent to respond to user interactions.
I'd highly recommend you take a look at the QGraphicsView examples to get an idea what you can do.
If you go the second route you'll need to record the different key locations so you can respond accordingly as the user moves the mouse around, clicks, etc.
This won't help you with your immediate issue but I wanted to show you a keyboard I made using standard layouts and buttons. It's not perfect and it still won't help you with an enter key that spans two rows but it's not bad. It's resizable too by resizing the window, although I'm not sure if that will be apparent from the images below as SO may be scaling them. (you can view the actual images by opening them in their own tab)
Anyway, this was done using only Qt Designer with no manual coding. It consists of a top level vertical layout with 5 horizontal layouts in it. The buttons are then inserted into one of the 5 horizontal layouts. The size of the keys can be controlled by setting the horizontal and vertical size policies to "ignored" for most of the buttons and then horizontal "minimum" for buttons that you want to be wider. Things can be tweaked by setting min and max size restrictions to buttons. When resized, the buttons will not maintain their relative proportions though, that would probably take some custom programming.
The styling in your example could be approximated pretty well using css style sheets and background images. Still not a minor effort but you should be able to get most of the way there without custom layouts and buttons.
I'm trying to figure out how to create a graphical interface, in X11, which exists outside of a window manager's/desktop environment's standard window frame. For example, when Thunderbird finds new mail, it shows a special alert in the lower right hand corner of the screen which is shown without any frame (no close/minimize buttons, etc.).
I'm specifically interested in doing this in QT with C++, but if someone knows a solution with a different graphical library, that would be helpful too.
For QT pass Qt::FramelessWindowHint as a window flag when you construct your top level widget.
See here for more info:
http://doc.qt.nokia.com/main-snapshot/qt.html#WindowType-enum
You can do this with X as well although I haven't done so in a long time.
http://www.xfree86.org/current/XCreateWindow.3.html
With GTK you would use gtk_window_set_decorated(), which would probably be Gtk::Widget->set_decorated() (I think, I don't use gtkmm).
http://developer.gnome.org/gtkmm/unstable/classGtk_1_1Window.html#a67adb1d8051a38e0e5272f141bb8778c
I want to divide the application screen into parts like one part is fixed showing fixed controls & another one is variable which can be changed when user select something. Like in Qt Creator we are having the left side column always fixed & the content of center screen is changing when user is selecting something. I have attached the screen shot. How to do it. if any one is having any idea please help me.
When you speak of the Qt Creator you certainly mean the controls on the left and right. In my opinion, the best thing to implement that are QDockWidgets. Have a look at them in the docs and as Martin said, look at the examples, they are perfect to learn each of the layout and composing issues.
QDockWidgets can be made floatable (undock them from the main window as toolboxes), they can have fixed sides to be docked on and it's easy to use them, because they can be filled with every widget you like. I often use them when I show a file explorer in an application, for example. Just look at the examples and play with it.
If you just want to have QActions visible all the time for the user, you can use a QToolBar.
You normally start with a QMainWindow and then put other toolbars, controls, widgets etc inside that.
Check out the Qt examples that come with the SDK src