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A few design questions...

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  • mzimmersM Offline
    mzimmersM Offline
    mzimmers
    wrote on last edited by
    #5

    You can just paint or mayby use opengl?

    I'm hoping to keep this entirely within Qt, for simplicity's sake. I seem to remember reading about the ability to tie a programmatic variable to a display element using Designer, but...I can't remember where I saw that, and I'm not figuring it out just by looking at Designer.

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    • Z Offline
      Z Offline
      ZapB
      wrote on last edited by
      #6

      I would seriously take a look at the Qt State Machine framework (QStateMachine, QState, QAbstractTransition etc). We make heavy use of this framework for modelling and controlling hardware devices. The hierarchical nature of the nested states and transitions maps quite nicely onto physical components or behavioural modes of operation.

      I am thinking that maybe you could use this framework to model your IC and then maybe hook it up to a QGraphicsView/Scene or QML scene for the visualisation aspects.

      Nokia Certified Qt Specialist
      Interested in hearing about Qt related work

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      • mzimmersM Offline
        mzimmersM Offline
        mzimmers
        wrote on last edited by
        #7

        Hey, Zap -

        That does look interesting, and it might be worth a closer look. For my education, though, can we put it aside and go through the same thing we did in the other thread, except making the display of the variables more "graphical?" I'd like to implement something along the lines of what I described above, even if only for the exercise. Besides, this summer, I'll be using Qt for more than a simulator. It will be a genuine GUI, and I need to learn about that.

        Thanks.

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        • Z Offline
          Z Offline
          ZapB
          wrote on last edited by
          #8

          You mean that you just want to learn how to display the results of your existing calculations in a more graphical way?

          If so, then I would take a look at QGraphicsView or QML. QGraphicsView is purely C++. QML is a new technology with a lot of promise. It is easy to write custom GUIs using QML but you'll need to be prepared to get to grips with exposing C++ objects to the QML side of things.

          NB: QML is actually built on top of QGraphicsView at the moment but this is likely to change in the future.

          I suggest that you have a read up on these two technologies.

          Nokia Certified Qt Specialist
          Interested in hearing about Qt related work

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          • mzimmersM Offline
            mzimmersM Offline
            mzimmers
            wrote on last edited by
            #9

            OK, I'll do that. A quick question regarding QML: is it suitable for a desktop app? Some resources say it's intended for mobile apps.

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            • A Offline
              A Offline
              andre
              wrote on last edited by
              #10

              QML can be used in a desktop app just fine, but it all depends on what you want to achieve exactly.

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              • Z Offline
                Z Offline
                ZapB
                wrote on last edited by
                #11

                Of course. You can simply use you QML scene as a single widget in your app rather than the entire application GUI. Just add a QDeclarativeView to your form and set it to use the specified QML file:

                @
                QDeclarativeView *view = new QDeclarativeView;
                view->setSource(QUrl::fromLocalFile("myqmlfile.qml"));
                view->show();
                @

                Nokia Certified Qt Specialist
                Interested in hearing about Qt related work

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                • mzimmersM Offline
                  mzimmersM Offline
                  mzimmers
                  wrote on last edited by
                  #12

                  OK, thanks, Zap. I'll look at QML more closely in the morning and see if it looks like it's what I want for this.

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                  • Z Offline
                    Z Offline
                    ZapB
                    wrote on last edited by
                    #13

                    Basically it is similar to what we already did in the other thread. The main difference is that instead of simply emitting a signal for your calculated values we declare those values as properties of the QObject (using the Q_PROPERTY() macro) and add a signal that is used to notify interested parties (the QML items) about changes to those property values.

                    When the QML runtime gets those signals it updates the relevent items in your QML scene that have properties bound to your C++ object's properties in some way.

                    It's not as hard as it sounds ;-)

                    Nokia Certified Qt Specialist
                    Interested in hearing about Qt related work

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                    • mzimmersM Offline
                      mzimmersM Offline
                      mzimmers
                      wrote on last edited by
                      #14

                      OK, I'll start on that in a bit. A couple of questions:

                      1. does using QML mean that I'm no longer using my widget.ui file, or do they work together?
                      2. regarding QML: I think I may have mentioned that later this year I'll need to design a genuine GUI (for products based on the ASIC that I'm currently simulating). Is QML appropriate for applications like that as well? I ask now, because I'd like to choose one method of implementation and stick with it for both the simulator and the product GUI.

                      Thanks!

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                      • A Offline
                        A Offline
                        andre
                        wrote on last edited by
                        #15

                        1: depends on your design. If you use a QML file for your whole UI, yes. Otherwise, the QML view is just a part of your UI design, and one that would be part of the actual .ui file.

                        2: to decide that, you need to tell us about the criteria, and even then it is hard for us to advise you on that. QML may be a candidate, but...

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                        • mzimmersM Offline
                          mzimmersM Offline
                          mzimmers
                          wrote on last edited by
                          #16

                          Thanks, Andre. Tell you what: I'll spend today playing with QML and doing some reading.

                          Regarding the upcoming product GUI: think of how you configure a home DSL modem, except we (probably) won't be using a browser to reach the embedded application.

                          I'll be back later with (I'm sure) some questions.

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                          • Z Offline
                            Z Offline
                            ZapB
                            wrote on last edited by
                            #17

                            QML or a QWidget based GUI will work fine for that. Depends how much you want in the way of animations or how much you would like it to look native on your target platform. Having said that QML can be made to look native and we may see some native looking QML components coming out in the course of the coming year.

                            Nokia Certified Qt Specialist
                            Interested in hearing about Qt related work

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                            • mzimmersM Offline
                              mzimmersM Offline
                              mzimmers
                              wrote on last edited by
                              #18

                              Not directly related to the thread, but I've stumbled across an issue that I've been wondering about.

                              I'm running on a Mac platform. The code that Zap posted above won't work unless I move my QML file into the resource for the binary. I don't like to do this, because 1) it's a minor hassle, and 2) it seems like a maintenance issue that I don't need.

                              Does Qt have any hooks for setting a default directory, or putting a prefix on files to direct them to somewhere else? I'm trying to avoid any hard-coding here, though some may be necessary.

                              I did find this thread:
                              "thread on setSource":http://developer.qt.nokia.com/forums/viewthread/656

                              Which seems related, but not quite the answer.

                              Any advice on how to handle this?

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                              • Z Offline
                                Z Offline
                                ZapB
                                wrote on last edited by
                                #19

                                I don't have a Mac to test on, but it should work. Just be sure to correctly specify the path to the qml file. Either via an absolute path or via a path relative to the location of your application executable (see docs for QDir).

                                Nokia Certified Qt Specialist
                                Interested in hearing about Qt related work

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                                • mzimmersM Offline
                                  mzimmersM Offline
                                  mzimmers
                                  wrote on last edited by
                                  #20

                                  Decisions, decisions. An absolute pathname, and I bet it won't port to other platforms. Relative pathnames seem weird here, too.

                                  I don't suppose Qt supplies a pathname for the project, does it? I can't see how it could, but that would solve the problem.

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                                  • G Offline
                                    G Offline
                                    giesbert
                                    wrote on last edited by
                                    #21

                                    What you can do is ionstall the file besides you exe and use QCoreApplication::applicationDirPath()

                                    Nokia Certified Qt Specialist.
                                    Programming Is Like Sex: One mistake and you have to support it for the rest of your life. (Michael Sinz)

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                                    • mzimmersM Offline
                                      mzimmersM Offline
                                      mzimmers
                                      wrote on last edited by
                                      #22

                                      What you can do is ionstall the file besides you exe and use QCoreApplication::applicationDirPath()

                                      True, but then the QML file is out of the source structure. I'm trying to preserve a separation between source files (of all kinds) and makefile output. It seems like good CM practice if nothing else. I guess I'm probably stuck with the relative pathnames, huh?

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                                      • G Offline
                                        G Offline
                                        giesbert
                                        wrote on last edited by
                                        #23

                                        Typically, you design the app so it will work on target machines with installed files, not with developer structures. Make it part of the makefile to copy the file to the out dir?

                                        Nokia Certified Qt Specialist.
                                        Programming Is Like Sex: One mistake and you have to support it for the rest of your life. (Michael Sinz)

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                                        • mzimmersM Offline
                                          mzimmersM Offline
                                          mzimmers
                                          wrote on last edited by
                                          #24

                                          Now THAT'S a good idea, and will obviate the issue completely. But...makefiles are automatically generated, right? How can I do this in such a way that will survive blowing away the makefile and regenerating it?

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