[Qt-qml] please help me decide if qml is the right solution for my project

[jyrki.yli-nokari at nokia.com]

Well, absolutely QML, no question about it.

  *   HTML is too slow and cumbersome to achieve the graphical richness you want to achieve. The benefit of HTML5 is to be able to run one UI on majority of desktops around the world.
  *   Why write your own view definition system as QML is precisely what the doctor ordered

Also, there is no other technology afaik that lets you define the graphics effects with shaders — definitely something a starship UI uses. See http://labs.qt.nokia.com/2011/05/03/qml-shadereffectitem-on-qgraphicsview



From: "ext mailings at novaimages.de<mailto:mailings at novaimages.de>" <mailings at novaimages.de<mailto:mailings at novaimages.de>>
Reply-To: "mailings at novaimages.de<mailto:mailings at novaimages.de>" <mailings at novaimages.de<mailto:mailings at novaimages.de>>
Date: Sat, 7 May 2011 17:12:22 +0200
To: <qt-qml at qt.nokia.com<mailto:qt-qml at qt.nokia.com>>
Subject: [Qt-qml] please help me decide if qml is the right solution for my project

Hi

my name is Thomas Ganshorn.
I use qt since about 6 years i think and am really happy about most of it.
Now i think about using QtQuick for a fun project of mine a starship simulation.
( http://www.novaimages.de/bridgesim )
But currently i am not sure if it is really "ready" to use and makes sense
(from a technical and coding efficiency standpoint)

The project consists of basically three parts.
A server application that simulates the starship and the gameworld.
A DataView application that needs to visualise many data in different forms (pie and line diagrams, radar screens, ... )
and a userinterface application.

For version 1 the server application and the dataview application where one app running on each machine.
They were developed with standard QT code having many parameters to define the look of them.
The userinterface are different html5 pages talking over the http protocol to the server applications.

Now i think about rewriting the userinterface and dataview mechanism but here comes the question, what to use.

i have basically three ways to go
- Use html5 for userinterface and datavisualisation
- use quick for userinterface and datavisualisation
- write my own "ViewDefinition system" that allows custom placement and configuration of my c++ (custom) widgets.

I want to
- have an easy way for others to modify the look and feel. Going from Battlestar Galactica to StarTrek or MassEffect
- fast userinterface because the machines used are not high performance
- touch capability
- remote userinterface capability (ui works on machine 1, server is on machine 2)


Pro HTML5
-> one userinterface library for all devices
-> simple to change look and feel by using css
-> webgl for 3d already integrated
-> canvas for drawing diagrams and other non trivial datavisualisation
-> i know how to use it
-> works on ios, android, ... too

Con HTML5
-> http protocol overhead is rather large
-> does not work so well with two different screens (one is a touchscreen, the other can only modified externally)


Pro "Own ViewDefinition" System
-> I know what to do
-> view and widget configuration will be easier for other people than myself

Con
-> It looks like a subsystem of QtQuick


Now my questions to qtQuick
-> It looks as if it needs much more c++ work to connect the ui to the system (just writing a datamodel is more work than otherwise necessary)
-> is it faster than eg chrome11 ? Probably graphics but the scriptengine ?
-> does it scale ? I do not have only a small phone screen, i have a large ui as you can see on the website
-> how to allow styling ?
       I want to provide a baselibrary of widgets the users can then use to create their userinterfaces.
       Is there something like css allowing global definition of colors, images or other style mechanisms ?
       (Having 100 buttons where i have to set the colors would be really annoying)
-> Is it more than just an experiment for smartphones and does it make sense to learn ?
    using html5 technices makes sense because you can use them in any other job to.
-> How stable is the system ? Will it change all the time so i have to redo the coding in c++ and qml ?


My concerns are
- the connection between QML and C++.
  If i see eg the Texteditor tutorial there is far more code than working traditionally and some real ... well kind of weird "workarounds" necessary
  which really give me a bad feeling
- html and css is rather common and many people can work with it. I do not want to write all the uis on my own, most probably defining some
  templates but the rest has to be done by non techies. Currently i fear qml would be way to much for them
- for datavisualisation (piecharts, line and pointdiagrams, ...) do i need to write my own c++ code ? Or is more complex drawing functionality then just
  some images and rectangles possible ?

So can you please help me decide ? What would you suggest ?

Greetings Thomas















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