How to combine Python logic and Qt C++ GUI - python

I was presented with a Python logic and a GUI written in C++ Qt and asked to combine them. Before I choose the route of re-implementing the GUI in e.g. PySide, I would like to know which way would be the smoothest to achieve such a combination. Would I rather make the C++ GUI available to the Python logic (and a controlling layer) or the other way around?
I will gladly provide more information, if necessary. My problem is a lack of experience in that matter and that there are so many solutions of how to make code of one language accessible to the other, that I feel a bit smothered in options.
In this case, the Python logic is actually just a (too large, but that's another topic) class which provides some signal processing methods.
This is a crisp rephrasing of a prior question, which I somewhat clumsily posed, and therefore missed its aim.

Related

How can I have a Macro like recording feature for PyQt

I have a Qt tablewidget and other Qt widgets adjoining it. What I am looking for a Automatic script generator that records all the actions that I would perform on the table or other Qt widgets. I had also worked with Enthought and they have a wonderful apptool enthought.scripting that helps me with the same but only for traits objects. I would like to do the same on PyQt widgets but dont know how.
This is one of those ideas that seems so natural, it makes you wonder why there isn't already a library out there that does it.
Well, it turns out that writing something that gets you 80% of the solution is pretty straightforward, especially if your app is small. But implementing a recording/playback system that works for a large app with a diverse array of widgets is quite a pain.
I wrote a library that does its best to solve this problem. It's full of hacks, and the code is still very immature (I just pushed the repo to github today), but you might get some ideas. Heck, if you're lucky, you might even be able to use it without any changes:
https://github.com/stuarteberg/eventcapture
There's no documentation yet. I plan to explain all the tricks to get this working, and probably clean up the code a bit. For now, you can at least get started by trying the demo as described in the Readme.
You could use the eventFilter method from your QApplication instance.

Framework for paint program

I've decided to start working on a personal project, attempting to develop a cross platform, MSPaint like app. Oddly enough, I find mspaint is one of the applications I miss the most on Linux or OS X, so I want to try to make something similar. Tuxpaint, mtpaint, gpaint, etc. are all old and inactive and ugly. I don't want to make GIMP, just the basics, similar in features to MS Paint.
I'm thinking of doing it in python with the pygtk toolkit, but I was interested to hear your suggestions. Would C/C++ be a better choice, or even C# (gasp!) with mono? How about using Qt as opposed to GTK, or maybe some other fancy library I don't know about (Please, not FLTK!). I'd be curious to hear your thoughts.
Thanks!
Qt's canvas object (or its newer replacement QGraphicsView) can do pretty cool things. Whether you choose C++ or python is a matter of personal choice, as Qt is supported in both languages. For a simple project like this I'd choose python because killer performance is not much of an issue, and it will be much easier to write.
Another thing to look into is making this app web based with HTML5's canvas object and Javascript. It can be surprisingly robust, and anything that can be put on the cloud is a win in most cases.
If you decide to go with Python (which would be my choice because it's such a simple language), then TkInter is considered the de-facto standard GUI package. That link should send you to some excellent starting references for TkInter, although I also really like Not_a_Golfer's suggestion of an HTML5 web-app.
Short: You can use both, no third party library is guaranteed to be distributed with all major distributions.
Long:
Gtk+ vs. Qt
What do you want incorporate into your application. If it is just selecting a brush, selecting color you could pretty much use any gui toolkit.
If you are going to run it as a web-based tool, Gtk+ has an html5 backend renderer (I don't know about Qt)
A sidenote:
I recommend to use the toolkit's native programming language (gtk+ C, Qt C++) - if you don't, you will suffer from delays with bugfixes, generally more bugs and delayed releases, though for that case it shouldn't really matter.
Everything else boils down to personal preferences and there already exist some questions to tackling that issue.
if you are using qt,you can use QtitanRibbon

python GUI compared to Swing?

I wanted to say "best python GUI compared to Swing"... but was sternly told my question was "too subjective". I apologise to the deterministic ghost in the machine.
I'm currently using Jython... have been using it for maybe 6 months now following years of Java. I love Jython's ability to call on all the Java classes, and also to ease the transition from a Java way of doing things to a Python way.
But thinking about it I realise that by far the most common Java packages I'm using are the Swing ones. I have spent many years wrestling with Swing and finally think I have the beast under some kind of body-lock. I also think Swing is wonderful, by the way, and I have to say that I am something of a keyboard fanatic, for example, so wouldn't want to switch to a GUI where you don't have power akin to that lurking in ActionMap-InputMap, which maybe not many people care that much about. It would also be a shame really to turn my back on JTree and JTable, having spent so much time tearing out what was left of my hair about them. Seriously, they are fiendishly powerful...
But at the same time I'm fast becoming hooked on the Python way of doing things. I can and intend to stick with Jython. But I was just wondering what the various CPython GUIs are like... and specifically how their power and versatility compare with Swing?
added:
I have been asked to provide some specifics: OK, what about a tree GUI object sitting on a scroll pane where it is possible, if you want to, to control navigation and collapsing/expanding of nodes using the keyboard... where the scrolling happens automatically (if you want it to) and where you have control over look and feel, etc. Or tables where you have comprehensive control over resizing, over what happens when individual cells gain/lost focus. Where you can subclass renderers and editors. As I said in my comment, someone who is/was keen on, and a big user of, Swing but nonetheless made a transition to a CPython GUI and was happy/unhappy... might be the ideal person to answer this.
I never done much with Swing, but Qt (and its bython bindings, PySide or PyQt4), matches all of your criteria as far as I can understand them.
Qt focuses on doing things as it's customary on the underlying OS. So the most obvious thing to do is usually the “right” thing to do, but if you want control you can go and override the look or behavior.
As for the pythonic way of doing things... The bindings are getting there. They still feel somewhat C++-ey, to be honest.
Also read some other questions on comparison between the two.
I think Python has many toolkit for GUI.
Java has Swing. If you want to develop
cross-platform friendly GUI,I suggest
wxPython.

Python Web/UI Options

We are in the process of standing up a UI on top of a python system. This is all throw away code, so we want something quick, yet presentable.
We will have a couple of "interfaces" but they will be of two types. One will be control, it will basically be sitting on top of a python thread, and accepting requests from the user.
The other will be more of a display screen that will need to be able to display images, and some classic "grid views" of text to the user.
We pretty much know we could* do all of this in HTML but wasn't sure what would be the best way to interact with the core python code?
Anyone know of a good UI python presentation layer? Since we know we can do all of this in HTML/Jquery pretty quickly, we are also open to suggestions on how to integrate this with a web server..
Any suggestions? Really interested in finding out if there is any way to use python as the back end to a webserver.
Let me know if you all need more information.
I like wxPython. The demo application is excellent and lets you browse, tweak and re-run the code right in the demo.
We have found the DJango meets our needs. It is a pretty slick mvc style python web stack. Really is easy to use, and very quick to develop in. I will say that the ORM layer is a little young so it is hard to do some simple queries, but luckly since this is throw away code we can just use native sql.
Tkinter is probably going to be the solution you can use quickest. Its API is simple and straight-forward, and you probably already have it installed.
As the other 2 classic Python GUI options have been given already, I feel duty bound to suggest PyQt :)
Using QT Designer I've found it much simpler than TKInter to get some basic GUIs up and running. Build your GUI up in a WYSIWYG way, then hook it up to the back-end logic. I've also found that the large amount of C++ help on QT available on the interent usually translates more or less directly across to PyQt. The resources available for TKInter are IMO pretty obtuse, and simply stop as soon as you want to do anything more interesting than Hello World. YMMV.
The Rapid GUI Programming with Python and QT book is a fantastic resource. Had me programming real applications in no time.

How to use python to create a GUI application which have cool animation/effects under Linux (like 3D wall in Cooliris, compiz effects etc...)

I am not sure if my question title makes sense to you or not. I am seeing many cool applications which have cool animations/effects. I would like to learn how to use python to create this kind of GUI applications under Linux.
"cool animation/effects" like 3D wall in Cooliris which is written in flash and compiz effects with opengl.
I also heard of some python GUI library like wxPython and pyQT. Since I am completely new to python GUI programming, can anyone suggest me where to start and what I should learn to achieve and create such application? maybe learn pyQT with openGL feature? pyopengl binding? I have no clue on where to start. thank you very much for your time and suggestion.
By the way, in case if someone need to know which kind of application I am going to create, well, just any kind of applications. maybe photo explorer with 3D wall, maybe IM client, maybe facebook client etc...
http://techbase.kde.org/Development/Languages/Python
Many KDE styles use SVG and plenty of animation. The user can always change themes. I think you should be more specific about what kind of animations you want to do. I don't think 3D wall type affects really fall into the widget category that QT is. It sounds to me like you want to make a 3D interface for an application. If that is the case, you may want to look more into 3D engine type libraries used mainly in games. I know that some have excellent GUI widgets for programming game menus and the like. I guess you'd decide on your engine and the see if there are python language bindings. One of my favorite engines: http://irrlicht.sourceforge.net/links.html
Another thing you would want to consider is how you want to handle the window management. Do you want to make a full screen interface? Or is to to be windowed? Also how would such an application integrate into a 3D window manager or rather a window manager with compositing.
Edit:
In that case the qtopengl module is probably something to look into: http://doc.qt.nokia.com/4.6/qtopengl.html
I do recommend QT. It's clean and easy to use and cross platform. So your app could run on windows as well.
One thing you'd want to think about before hand is the type of FX you want to perform. For example, if you want to create a page curl type effect when renaming the image, you'd have to think about how to program that, or look for libraries/code snipets that do that math. 3D engines that are used in games often have a lot of support for those kind of typical FX or animations that you'd see in a game. If you use something like qtopengl, you'd need to think about this as well. qtopengl can pretty much only render. Think of it as a viewport. However, it is the correct approach to making a 3D application for the desktop.
Programming 3D applications is really interesting and fun. I enjoyed it a lot. However, don't get discouraged be the math. I recommend getting a book about it if you are serious. I liked this one: http://www.amazon.com/Primer-Graphics-Development-Wordware-Library/dp/1556229119
However, IIRC the examples are C++ which you may not be comfortable with. When you understand such mathematical concepts, it easier to think about how you would make a page curl type affect. Of course, if you find libraries or code that shows you how to do the math, that may be fine.
May be, just create a GUI and all effects will make compiz?
Anyway, as I know QT have ability to use openGL.
http://doc.qt.nokia.com/4.1/examples.html#opengl-examples

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