Is resolution independent UI possible directly using QtDesigner? - qt

I want to create a UI which remains the same in all possible resolutions. I started with the Qt Designer wherein I set the geometry of my design window and when I change the resolution , the UI is not the same.
Things I tried:
1.I got the screen resolution using QT API and created a window programmatically to that resolution.But if this is the right approach,then I have to add other components programmatically. But my UI is quite big and it is time consuming creating all the UI components programmatically.
I looked at the following links:
Hand Coded GUI Versus Qt Designer GUI
Qt Creator - How to write the UI?
Is it possible to rescale a Qt GUI without rewriting the code?
but still I am a bit unclear of how to proceed.
Is there any way to achieve resolution independent UI using Qt Designer itself?If so, what is the approach?Else what is the work around?

Related

Layout required in designer but not in hand coded app?

I'm new to Qt and it's quite a learning curve!
I've been search/reading/hacking and learning for most of the day on this one.
I'm working on an app that will have a image in a scroll area as it's main purpose. The image viewer example is where I started. This example appears to be "laid out by hand" if you will - i.e. there are no .ui form files for it (it's trivial so why not).
So here is the rub - I want to use designer to build a much more sophisticated app. If I start fresh with a new project and use designer the resizing doesn't work unless I add layout (used vertical, all appear to fix the resize issue) to the .ui form.
Designer creates a lot more code to do the same thing - I don't care, it is after all an IDE / code generation tool.
However it's not clear to me why the layout is required when I use designer and not if I code it by hand. I searched the code for the image viewer example and there doesn't seem to be ANY layout involved at all, just 3 or 4 nested widgits (Main/Scroll/Label).
Is the default layout basically built in?
The example you linked to uses a QMainWindow. This widget has its own layout because it has built-in support for menubars, toolbars, dock widgets and a statusbar:
Main Window Framework:
Normally, the widget set as the central-widget would need to have a layout explicitly set on it in order to layout its own child widgets. However, in your linked example, the central-widget is a QScrollArea, which also happens to have a built-in layout. This is all just coincidental, though. The large majority of widgets don't have a built-in layout, so most GUIs will need to explictly add at least one layout, and several will usually be needed for more complex applications.
I would say Qt Designer is absolutely essential when it comes to experimenting with layouts (especially when you start learning Qt). Even if you don't actually use the ui file, it's still very helpful to just view the code that would be generated from it.

How to use OpenGL in QT Creator

I am working on OpenGL to create a GUI .I want to create some tabs which will help me to display different things in different windows. How is this possible using OpenGL? I read in some articles that we can use QT for that. Since I have already developed some of the GUI part in OpenGL using GLUT library ,is it possible to use the same code in QT? If so brief me how to make settings for OpenGL libraries in QT creator.
In my GUI I am trying to create a Car which is following a track.
I think you might be mixing some things up: OpenGL is a API with which you can instruct drivers to draw visual primitives, like lines, boxes, 3D triangles, pictures from buffer onto a render plane.
GLUT is a library that gives you a minimal environment around that, ie. it handles creating a window etc.
Neither of them are high-level UI description tools. Qt is really most likely what you want, as it will not only give you things like tab widgets etc, but also a feature-rich framework to do things like defining what should happen when you click a button, close a window etc.
There's a lot of examples of OpenGL usage within Qt widgets. In fact, a lot of visualization frontends use Qt and OpenGL. Qt has extensive documentation on how to generate OpenGL contextes and draw inside Qt applications.

Qt ui on top of c/c++ code

I saw this thread: QML UI on top of OpenGL rendering in Qt5.3 but it's not what I am looking for.
My question is if I have a program already written in c/c++ and would like to add ui to it in the most cross platform way. Qt seems to be the way to go, is it possible to just link the Qt library 'hopefully not too large' into my application and create menus, buttons etc that work in a cross platform way?
I don't want to build my app using Qt, I just want to use the layout widgets, menus etc.
I don't want to build my app using Qt, I just want to use the layout widgets, menus etc.
What?
In any case you should make an UI (using Qt Widgets or Qt Qml) and UI logic, and connect it to your app API. Just add UI layouts (using Qt Designer) and connect UI actions for button/menu/etc. to your app.
Qt - is the most cross-platform way to go, today.

Creating a home screen for my embedded board using Qt/Qt Quick

I am not an expert but I have been using Qt/QtEmbedded for sometime now, for SBC 6845. I have created a few applications and have successfully run them on my device.
Now I want all of those applications to appear on a home screen. I understand that using QML/Qt Quick this might be achieved, but I don't have any idea on how to proceed with it. I have gone through some links and tutorials but most of them show how to create buttons and all that with Qt Quick, but not much than that. I am yet to find some tutorial/docs which can point me how to proceed with all applications on my home-screen. I need some directions, any links, advice on docs/books is welcome.
[While cross-compiling the QtEmbedded 4.6.2 libraries for my SBC I encountered problems with enabling opengl support. And, I am unaware of the other methods for using QtQuick2 without opengl.
The applications (5-6 of them) are QWidgets and linking icons require to stay in the home screen. I want to keep them as simple as possible without any effects for the icons.
Plainly speaking, I am trying to create a bunch of icons displayed on the home screen linked to those applications. The applications if launched in windows style application, (or like a popup QDialog) will also serve my purpose.]
Thanks.
"I have gone through some links and tutorials but most of them show
how to create buttons and all that with Qt Quick, but not much than
that"
For this part of the question, I'd advise you to download QtCreator
and start playing with the demos (using more than just some buttons:
you have demos for ListViews, GridViews, Delegates, Animations,
Particles, QtQuick Layouts (Qt5.1 only), QtQuick Controls (Qt5.1
only).
There's also the rather complete :
http://qt.gitorious.org/qt-labs/qt5-everywhere-demo
I'm completely unfamiliar with all the embedded/cross-compiling
aspects of your question.
About OpenGL/QtQuick2 : http://qt-project.org/forums/viewthread/30483
http://qt-project.org/forums/viewthread/17201
Also note that you can embed QtQuick2 scenes into a QWidget, but not
the other way around (no QtWidget inside the scenegraph).
So maybe the easiest/fastest way to go for you would be to stick with Qt4 or Qt5 declarative/QtQuick1 module (might be deprecated/removed starting with Qt 5.2). In this setup, there is no scenegraph/mandatory need for OpenGL. And you can embed QWidgets into your qml scene (no scenegraph: it uses the QGraphicsView backend) via QGraphicsProxyWidget.
You'd then have some GridView (you also could use some Grid with a Repeater) filled with models and delegates (= a delegate acts as a template item to be filled with the model).
Your delegates would have states/maybe Loader(s) (for on-demand loading) : icon state and when clicked, some maximized state containing a loader, loading your widget through QGraphicsProxyWidget.
You already have half of this presented in this example (a grid + 2 states : small icons grid and maximized view, you only need to implement the delegate/loading/model/QGraphicsProxyWidget things):
http://developer.nokia.com/Community/Wiki/Implementing_parent_change_animation_with_QML

Embedding Qt GUI into existing OpenGL program

I'm currently trying to get Qt working with my existing program.
I'm using SFML for creating my OpenGL rendering context and creating the window. The things I tried out so far however always create a separate window by Qt instead of just rendering into the existing context.
Is there any way I can force Qt to render to an already existing OpenGL context?
I've not looked into the specifics, but this has been done for openage.
I think looking at the documentation for QQuickRenderControl might be a good place to start.
Qt wants full control over the windows and the event loop, so this will not work (unless you put a lot of effort into it). Your best bet is using a QGLWidget and emulate the event management of SFML with that, so that your application effectively runs on Qt. It is very well possible to render Qt widgets into a OpenGL window (Qt has a OpenGL widget backend) but this must be still managed by Qt itself.

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