How do you port a Cocoa/Mac application to Windows? I mean how would you go about it? Assume the app was written with Objective-C and Cocoa, there's nothing fancy going on, no "engine" that could be factored out, etc.
Rewrite from scratch? I don't think there will be huge overlaps between the Mac and Windows codebases, right?
I have doubts about cocotron.
Its not clear from the cocotron website that cocotron is actually production ready yet. Id suspect that it would be possible to start new app development and use cocotron constantly to maintain and test windows builds on the go.
But to retrofit it into an existing project might be a much larger task. There are also no alternatives to cocotron - other than perhaps gnustep.
The practical approach to cross platform development involves developing the non gui components of your application, once, in C or C++. And then using a cross platform GUI library like QT - which is VERY good at generating and using native UI where possible or faking it where not. Please DO go to qt.nokia.com and download the latest build of QTCreator for windows and mac - See how the same QT application looks and feels very convincingly native on both platforms.
If QT doesn't provide a native enough solution, then you need to develop your GUI twice :- once in Cocoa, and once in Win32. The cocoa GUI would be in objective C of course, the Win32 GUI in C/C++.
Your non gui application code would - written in c++ - not be able to call Objective-C directly, but its not hard to write shim classes, implemented in .mm files - the provide a c++ interface, and wrap access to an objective c object or class.
You are also going to have to come up with an alternative to CoreData on windows - perhaps sqlite? Given that XCode has integrated support for the sqlite framework, and testing multiple code paths is, well, more work - perhaps dropping CoreData in favor of a common layer is a better approach?
The problem with Objective C is its very poor support on any platform that is not OS X. You can attempt to use the Cocotron, but I wouldn't consider it production ready yet.
For portability, a re-write is in order. With judicious use of standard C or C++ for the "core" of the application, you could still implement platform specific GUI code. If you don't like maintaining two GUIs, you can also try a toolkit such as Qt
Depending on which objects and framework you are using for your cocoa app, you might be able to get away with using gnustep, although the end result will probably look very weird to windows users, and the development environment might be a bit difficult to setup at first.
Are you aware of Cocotron? It looks like the project may have gone stale, but it's a good starting point anyway. It's a project to port Core APIs.
If your application is not cleanly separated (ie: a la MVC) then the only solution is a rewrite, I think.
Related
Apple has killed Carbon for 64 bit applications. I've got a pile of legacy code that targets carbon UI widgets that I'd like to keep alive for a while. Most of it is in the form of plugins and bundles that will have to go 64-bit in sync with their host platform.
The choice that Apple seems to be assuming is to throw all the legacy code away
and rewrite using Cocoa. It's not going to happen in the short run, if only because
the same legacy code is tied to a PC binding as well.
I'm considering 3 Options
(1) Dive into cocoa, create a compatibility package that supports the small subset
of carbon that I actually need.
(2) use Cocoatron as the new target. In the short run bridge carbon-to-cocotron, and maybe in the longer run convert to cocoatron native for both mac and pc. (ref: http://cocotron.org/)
(3) use QT as the new target. See option (2). (ref: http://qt.nokia.com/)
What I would really prefer is a fourth option, such as a bootleg copy of the 64 bit
Carbon beta that Apple killed, or a compatibility package explicitly intended just
to emulate carbon.
I would recommend you choose option 1. Creating a Cocoa UI wrapper for your code will likely not be as complex as you think. A common way to create a cross-platform app is to create the bulk of the app in cross-platform C++ and use Cocoa/Objective-C++ for the Mac UI and one of the Windows APIs for the Windows UI.
This option also has the advantage that it is fully supported by Apple and the APIs are stable and mature.
Cocotron is a nice idea but as of now it's not mature enough (in my opinion) to provide a robust cross-platform solution. I know there are successes with it but the sample size is small.
Qt is an option. However, it suffers from a very un-Mac-like UI. Using a Qt app on the Mac always feels like a quick port rather than a native app, and this is unlikely to ever change.
The "bootleg Carbon runtime" is just a fantasy, there is simply no way to get that working reliably and absolutely no chance to distribute it. You will need to find another way.
I'd like to develop a desktop app with Ruby. However, I'd like to have a native GUI on every platform (as opposed to a cross-platform GUI Toolkit that looks consistently awful across all platforms).
I expect to have to do different GUIs for each platform (as it's not just looks but also behaviors and idioms that are different), but I wonder what my options are? Especially wondering if there is a clean way to separate front and backend and bind the data properly?
Target Platforms are Windows (Vista & 7, XP is a Bonus), Mac OS X (Cocoa) and Linux (GTK? Qt? No idea).
The Ruby language has excellent Qt library bindings and your scripts will be cross-platform.
Two Kinds of Cross-Platform
It turns out there are two kinds of cross-platform UI toolkits.
One kind draws its own controls, and, like you said, looks equally bad on all platforms. Even worse: it looks out-of-place on all except one.
But there is another kind that just provides a harmonized interface to the native widgets. The best of example of this kind of toolkit is SWT1.. It looks, it is, approximately fully native on each platform, yet it has but a single API.
So you shouldn't simply rule-out all cross-platform toolkits, just rule out the ones that fake the native UI.
Develop the Wrapper Interface
There is a second way. If your program's interface with the user can be directed through a relatively narrow interface, you can simply develop to that interface and then implement the bottom part of it for each platform you want to support. Yes, you have to rewrite one module, but all the other modules stay exactly the same and you get native widgets. You also get the smallest possible executable without lots of bloat.
Perhaps most importantly, you don't have a complex and opaque software layer between your code and the native windowing system. You will probably save as much time debugging as you spend writing the extra module for your first port.
1. I know my Java examples won't help you much unless you are using jRuby, but SWT vs Swing is a really pure example of the right-vs-wrong (IMHO) UI toolkit divide.
The WxWidgets interface claims to use the native interface on Windows, OS X, Linux and UNIX through one API.
Coworkers who have used it in the past enjoyed it well enough, but I've not used it myself.
I would like to build a graphical application that must work on at least Windows, Linux and MacOS. I would like to know what do you suggest I should use.
I have some experience with Java and C++ but I thought about using Java Swing first. What do you think or further suggest (like maybe tools or frameworks)? I also may be needing to connect to a PostgreSQL database to store data.
Java is probably the simplest way to get your application working on all 3 platforms as well as to add database support. All of these are equally possible in C++, but it definitely involves more work because you need to learn to use a cross-platform widget toolkit. Also, C++ database drivers usually have wildly varying designs but Java presents a unified interface via JDBC - this also means that you can change your underlying DB at any time without having to change your code.
I would use the Qt platform from Nokia. It supports all the OSes that you've mentioned and has also database connectors for PostgreSQL but also for MySQL, SQLite, etc.
It also has a very nice IDE, the QT Creator that you can use should you pick Qt.
I would suggest Qt too. Qt has seen very good development recently, their examples and documentation base is quite large, and the LGPL license is flexible too, for creating proprietary software. It has a good Qt Creator IDE, a Qt GUI Designer. Plus is has quite a number of modules, enabling it to be used in conjunction with other language developed apps/libraries. And, it is used in commercial/public apps like Google Earth, Skype (maybe only the linux version). So, it has a good history of reliability. And yeah, for Database, it has modules, like Qt-Sql. Another advantage you get over java is speed.
wxWidgets does cross-platform easily enough, using available native toolkits. You could probably use a ORM for the database part, but I don't have enough experience using them under C++ to provide an actual informed opinion there.
GTK is cross-platform. Pidgin uses it and manages to get away with being generally considered a fully-cross-platform app. The installer size is a problem, though.
In the wikipedia article on Cocoa it says:
There are also open source implementations of major parts of the Cocoa framework that allows cross-platform (including Microsoft Windows) Cocoa application development, such as GNUstep, Cappuccino, and Cocotron.
Yet when I looked into whether Mac application Tweetie was available for windows the developer had ruled it out:
Windows doesn't have Cocoa, the programming environment that Tweetie is made in, as such, it seems like a poor possibility.
I'd like to have an answer to point the Tweetie developers (and as a resource for other cocoa developers) which would tell them:
Which implementation is the most suitable for getting a cocoa app running on windows?
How much work is it likely to take to get the app running under windows?
How easy/hard is it to maintain a common code base for Mac and Windows?
(any other considerations I've missed?)
Of course if it would be too much work I'd like to know that too before suggesting it and potentially sending someone else on a fruitless search.
Don't forget:
“Major parts of the Cocoa frameworks” is not the same as “the entirety of the Cocoa frameworks”. Tweetie could be using something that's missing.
Tweetie could be (very probably is) using APIs from the non-Cocoa frameworks, such as Core Foundation, Core Services, Core Graphics, and Core Animation. A port of the Cocoa frameworks alone won't include any of these APIs, and even a more complete Mac-API-emulation framework will not include all of them.
These frameworks are eternally chasing Apple. Even if they catch up, they'll be instantly behind again as of the next Mac OS X release. Mac developers already put off using new APIs in new Mac OS X releases while they wait for users to upgrade to those new releases; now you're asking atebits to also wait for the other-framework developer to catch up to Apple again.
Any second implementation of an existing API will have bugs that the first implementation doesn't, and vice versa. These differences will cause development and support problems.
You're asking atebits to add a third platform to an application that already exists on two. Supporting one platform is a lot of work. Supporting two platforms is a hell of a lot of work. Supporting three? Now you're getting into big-company territory.
So, even with these Cocoa-like frameworks, the answer is: Hard.
Among GNUstep, Cappuccino and Cocotron, Cocotron is only possible choice to port a Mac application to windows.
Cappuccino is for web and GNUstep only runs on top of cygwin or mingw, which means the GUI looks nothing like native windows apps.
It is theoretically possible to build cocoa windows apps using Cocotron. However, the reality is that it is still very hard to use, and it is still quite limited in the Cocoa API.
Therefore, two possible solutions:
Try hard to remove the codes that are not supported by Cocotron in the original code base and do the cross compilation. Maintaining common code base will be painful.
Start a new GUI at all, no common code base. two choices here
Start a cross platform project with cross application framework such as Qt, or Java.
Start a windows only project. There are a lot of choices here, .Net WinForm application, MFC, etc.
There are Windows compilers for Objective-C (the programming language used to write cocoa apps). However, Cocoa includes the frameworks for presenting the GUI. These visual frameworks are specific to Mac OS X because they use OS X only windows and other controls. So someone would need to re-implement the controls in Cocoa to use Windows controls.
Also, I am fairly certain that Tweetie uses Mac OS X only technologies like Core Animation. This does not exist on Windows, so the nice animation effects present in the apps would have to be implemented in a completely different way.
I want to write a front-end to an application written in C/C++.
I use Solaris 10 and plan to port the application to some other architectures (Windows first).
I'd recommend taking a look at wxWidgets to provide some cross platform UI widgets that will work on Solaris and Windows.
Qt 4 is the best tool for this job. If you want to work with other languages, it also has bindings for Java and Python
On a Mac, this would be easy. The Cocoa API is great when programming in Objective C (which compiles fine with C/C++ files).
Otherwise the situation is a bit more grim. As for Rapid prototype, you might want to check the CodeGear (Borland/C++ Builder) tools. I think their VCL library is cross-platform.
Otherwise, you could interface with a scripting language like Ruby and use fantastic front end libraries like Shoes. Python also interfaces with wxWidgets to make writing cross-platform front ends easy. Keep in mind that this all requires taking time to make sure your C/C++ code can talk to the scripting language. This is not trivial, and the amount of effort required depends upon the style of your code base. (Oh my God.)
Lastly, you could just use wxWidgets itself. This might be your best bet since it requires no additional overhead than coding the UI itself. That said, C++ is not the greatest language for designing UIs.
And super lastly, consider writing a code generator that converts from say Shoes to whatever wxWidgets code is needed to generate the same Shoes app. That way you can do easier UI design but still get C++ code in the end. Likewise, you could code gen off of the Python/wxWidgets code. Then sell such a code generator. :-)
GTK-- and Glade.
Thats' the C++ bindings on GTK
GTK will work on windows ( just look at GIMP )
Works everywhere, no QT license to mess with your millions-making.
I use wxWidgets myself. It makes good use of the C++ language features and uses smart pointers, so object and memory management is not that hard. In fact, it feels like writing in a scripting language.
Coupled with a dialog editor/code generator like wxFormBuilder or wxDesigner, (links to screenshots) it becomes a good toolkit for rapid development.
Have a look at FLTK which supports X11 and Windows.
Ultimate++ is a cross platform rapid application development framework for C++. It is aimed specifically at rapid development. The Ultimate++ website provides some comparisons to other frameworks mentioned such as Qt and wxWidgets.
I have used ASP.NET Web Forms to make UI front-end to collection of command line application written in legacy language, RESTful-ish web service, and bash scripts.
Once it works on Firefox, it should work at least on Firefox on other architecture. If you haven't played around with it, you should give ASP.NET a try (ASP.NET MVC seems to be the current trend). Not quite the same as RAD, but it does give you visual design of forms etc.