Crystal native GUI - user-interface

Does Crystal possess any native GUI libraries ?
There is already a few shards that implement known libraries such as QT or SFML ( anything related to C in fact ) but i need a native library as I do not wish to have any extra downloads and keep the project light.

No, there aren't any GUI libraries written in Crystal.
And I doubt we will see one anytime soon - or ever. These are incredibly huge and complex pieces of software. There exist only a handfull of modern general-purpose GUI libraries at all. Because it requires so much effort to create a halfway decent GUI framework, the few ones available have a broad target audience. Most of them are written in C to make them available for many languages and platforms.
Crystal is great at interfacing C libraries and thus existing libraries can be integrated relatively easily. That still requires lots of work because of their size, but it's only a fraction of writing a new one just to have it in Crystal.
Besides, there is no gain in reinventing the wheel.
If you want to cut down runtime dependencies, you can try static compiling. There are still some glitches IIRC but it will work eventually.
Allthough, since there exist only a few GUI libraries, they are usually available on most platforms and can be easily installed through package managers.

Related

Comparing Qt4 with Cocoa

I'm on the beginning slope of learning Mac programming and in particular Cocoa. It seems to be a comprehensive framework providing all kinds of things every app programmer needs. Qt4 is the same sort of thing at a general level, except it runs on other platforms and uses C++ instead of Obj-C. More importantly for me, I've used Qt4 and so am familiar with it, though hardly expert. I am new to Obj-C and app programming in general, but know C++.
I'd be interested in comparisons of Qt4 and Cocoa, tips for those starting one coming from the other (either way), and discussions on their internals, API design, intended uses, how the designers of each made decisions about how things should work, etc.
What are some recommended readings?
(Of course, I want serious writings by professional developers with real experience with both, not flame wars or fanboy gush or marketing pablum.)
So far I have used Qt4 to implement some cross-platform applications (Windows & Mac) and I used XCode (Objective-C) only for iPhone Applications development - therefore I don't have first-hand experience in using Objective-C for native Mac applications.
I think the best advantage of Qt4 is portability, and I love it for it.
Not only you may port the entire Qt Application to different environments, but with a small effort you can create standard C++ libraries (libraries that not use Qt4 Classes) which are far more useful and portable.
On the other hand, I think the XCode/Objective-C environment is more mature regarding project management and UI Design and off-course you can use the full set of Mac-OS native calls in your application. As you may know Objective-C is fully compatible with C++ and you can use any third party C++ libraries, but if your main environment is XCode/Cocoa you will finally find yourself writing mainly Objective-C code which cannot be ported to any other environment but Mac-OS/iOS.
Therefore to cut a long story short, I think your decision must be based more on your long-term needs than to any environment/design/language/API details:
=> If you know that you will build Apps for Mac-OSX (or iOS) for the next 1-2 years and there is no portability requirements, go with the XCode/Objective-C approach to create a more solid base for Mac Application development.
=> If this is a "Just One Mac/OSX Application" thing and then you will return to Qt4 or another environment, maybe it's better to stick with Qt4, enjoy the advantages of portability and use the experience you already have to reduce the developing time.

Is there any cross-platform GUI Toolkit which does not follow the one source to rule them all concept?

After a long evaluation period of mainstream toolkits Qt, WxWidget, GTK i came to the conclusion that it does not make sense to religiously equalize the different platform. Now more then ever before.
In the days before Java portability meant, that platform dependent code was located in known places and should be small but not none. No write once, run everywhere marketing.
Is there any GUI tookit - experimental or commerical (even outdated or dead projects) - that is going this way. It would need to give me native widgets of course. I would like to have a look at them before i start my own toolkit
If you think this is a stupid idea tell me why (cause everybody else is doing it differently there may be a reason i don't see)
As someone who zealously believes that GUIs should be drawn with native widgets, I must say I've been very impressed with wxWidgets, although you mention that at the beginning.
As far as I know, wxWidgets uses native widgets whenever possible, and indeed it does also include platform-specific features that are neither possible nor relevant on other platforms. A good example of this is how you can use the native Mac OS X menu, while on other systems it won't do squat. There are other and better examples.
I must mention wxPython in particular, in case you either don't want to or just don't have the time to write a C++ program. wxPython astonished me when I tried it out first, and I even managed to make a stand-alone .exe file from it that worked on a fresh install of Windows 2000 without any updates or particular runtime environments.
If wxWidgets doesn't suit your needs, I wonder what would. :) Hurray for wxWidgets!
AFAIK, wxWidgets uses the platform's native widgets whenever possible.
Have a look at SWT, it tries to use the widgets of the underlying platform as much as possible.

Haskell UI framework?

Is there, by chance, an emerging Haskell UI framework for Windows?
I recently took up looking over the language, and from what I see, it would be for great little "one-off" applications (elaborate scripts).
However, without a good UI framework I can't see it getting in under the smoke and mirrors of the more obvious contenders.
I've read that there are many frameworks, but none are full-featured.
I'm just wondering if this is something that's on the rise, or is it simply too difficult to get enough developers going in the same direction with one?
The two main frameworks are wxHaskell and Gtk2Hs. Both of these have been used for real work. From what I know my preference would be Gtk2Hs because it handles resources properly (i.e. uses the GC). wxHaskell requires the programmer to release widgets once they are no longer required, so you can get all the classic memory leaks and stale pointer screws with it.
The problem with both is that everything is in the IO monad. This reflects the fact that they are comparatively thin wrappers around existing GUI libraries for imperative languages. Of course this means you are no worse off than you would be writing a GUI in an imperative language, but you are hardly much better off either.
There are some interesting experimental libraries to be found on Hackage, including Grapefruit and Conal Elliott's "Tangible Values" ideas in GuiTV. Both of these try for a more declarative approach.
(Disclaimer: I am the wxHaskell maintainer)
Both wxHaskell and Gtk2Hs are more or less complete. That's to say, both wrap a great deal of the functionality provided by their underlying libraries. They also both, as mentioned earlier, require a rather 'imperative' style of programming in the IO monad.
There have been many discussions on the relative merits of each. I would say that wxHaskell is the easier of the two to get working, especially on Windows, as it can be installed via cabal (see http://www.haskell.org/haskellwiki/WxHaskell/Install#On_Windows)
The FRP frameworks (Grapefruit and others) provide a more 'functional' style of programming, at the cost of having much reduced widget coverage. I have the feeling that this is still an open research area, and not really ready for 'prime time'.
In practice, I've never had resource management issues with wxHaskell, although I agree that it's possible, and is an area handled better by Gtk2Hs, which uses reference counting in the underlying library.
For completeness, I should also mention that a Qt binding (QtHaskell?) also exists - it is relatively young, but apparently reasonably complete.
I rather feel that the Haskell community, small as it is, would do well to fix on one GUI framework, but accept the difficulty of this (e.g. licensing, support for all OS platforms etc.).
Also you can use wxWidgets (i mean C++ library) with Haskell. Here is an example: https://bitbucket.org/afiskon/hs-a-star-gui/src Such approach has some advantages over wxHaskell: 1. You can use UI generators (Code::Blocks, wxFormBuilder) 2. Your application takes less disk space 3. You can use all features of wxWidgets.
It should also be noted, that last version of wxHaskell uses wxWidgets 2.9, which probably will never be ported to Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=16;bug=613431

How does porting between Linux and Windows work?

If a particular piece of software is made to be run on one platform and the programmer/company/whatever wants to port it to the other, what exactly is done? I mean, do they just rewrite linux or windows-specific references to the equivalent in the other? Or is an entire rewrite necessary?
Just trying to understand what makes it so cost-prohibitive that so many major vendors don't port their software to Linux (specifically thinking about Adobe)
Thanks
this is the point of a cross-platform toolkit like qt or gtk, they provide a platform-agnostic API, which delegates to whichever platform the program is compiled for.
some companies don't use such a toolkit, and write their own (for whatever reason - could well be optimisation-related), meaning they can't just recompile their code for another os.
There are also libraries available that ease, at least on a specific area, the port of Windows API calls to Linux. See the Windows to Linux porting library.
In my experience, there are three main reasons why it's cost-prohibitive to take a large existing program on one platform and port it to another:
it has (not necessarily purposely) extensively used some library or API (often GUI, but there are also plenty of other things) that turns out not to exist on the other platform
it has unknowingly become riddled with dependency on nonstandard features or oddities of the compiler or other tools
it was written by somebody who didn't know that you had to use some oddball feature to get things to work on the other platform (like a Linux library that isn't sprinkled with the right __declspec directives you need for a good Windows DLL).
It's much easier to write a cross-platform app if you consider that a design goal from the start, and I have three specific recommendations:
Use Boost—oodles of handy things you might ordinarily get from platform-specific APIs and libraries, but by using Boost you get it cross-platform.
Do all your GUI programming using a cross-platform library. My favorite these days is Qt, but there are other worthy ones as well.
Build and test every day on both platforms, never provide an opportunity for the code to develop a dependency on only one platform and discover it only too late.
There are many reasons why it may be very difficult to port an application to a different platform, most often it is because some interfaces the application uses to communicate with the system are not available, and one either has to implement them on their own, port a library your application depends on, or rewrite the application, so that it uses alternative functions. Most languages today are very portable across hardware architectures and operating systems, but the problem is with libraries, system calls and potentially other interfaces the OS (or platform) provides. To be more specific:
Compilers may differ in their configuration and the standard functions they provide. On Windows the most popular compiler for C/C++ is Visual Studio, while on unix it is gcc and llvm (in combination with the standard library glibc or BSD libc). They expect different flags, different forms of declaration, produce different file format of executables and shared libraries. Even though C and C++ have standard libraries, they are implemented differently across platforms. There are some systems whose aim is to make compilation portable, such as Autotools, CMake and SCons.
On top of standard libraries there are additional functions OS provides. On Windows they are covered by win32 API, on unix systems these are part of the POSIX standard, with various GNU, BSD and Linux specific extensions, and there are also plain system calls (the lowest-level interface between applications and the operating system). POSIX functions are available on Windows via systems such as cygwin and mingw, win32 API function are available on unix via Wine. The problem is that these implementations are not complete, and often there are minor (but important) differences.
Communication with the desktop system (in order to make a GUI interface) is done differently. On Linux this might be the X Window System (together with freedesktop libraries) or Wayland, while Windows has its own systems. There are GUI libraries which try to provide an abstract interface for these, such as Qt, GTK, wxWidgets, EFL.
Other services the OS provides, such as network communication may be implemented differently. On Windows many applications use .NET libraries, for which there is only limited support on unix systems. Some unix applications rely on Linux-specific features such as systemd, /proc, KMS, cgroups, namespaces. This limits portability even among unix systems (Linux, BSD systems, Mac OS X, ...). Even .NET libraries are not very compatible across different versions, and they might not be available on an older version of Windows or on embedded systems. Android and iOS have different interfaces entirely.
Web applications are usually the most portable, but HTML5 is a live standard, and many interfaces may not be available yet in some browsers/web engines. This requires the use of polyfills, but it is usually much less painful than the situation with "native" applications.
Because of all of these limitations, porting can be a pretty hard work and sometimes it is easier to create a new application from scratch, either specifically for the other platform, using cross-platform abstraction libraries/platforms (such as Qt or Java), or as a web application (potentially bundled in something like Electron). It is a good idea to use these from the beginning, but many programmers choose not to because the applications tend to look and behave differently from "native" applications on the platform, and they might also be slower and more restricted in the way they interact with the OS.
Porting a piece of software that has not been made platform-independant upfront can be an enormous task. Often, the code is deeply ingrained with non-portable APIs, whether 3rd party or just OS libraries. If the 3rd party vendor does not provide the API for the platform you are porting on, you are pretty much forced into a full rewrite of that functionality, or finding another 3rd party that is portable. This only can be awfully costly.
Finally, porting software also means supporting it on another platform, which means hiring some specialists, and training support to answer more complex queries.
In the end, such a process can be very costly, for very little additional sales. Sadly, the decision is easy: concentrate on new functionality on your current platform that you know your customers are going to pay for.
If the software was written for a single OS, a major rework is likely. The first step is to move absolutely all platform-specific code into a single area of the code base; this area should have little or no app-specific stuff. Then rewrite this isolated portion of the code for the new target OS.
Of course, this glosses over some extremely major implications. For instance, if your first version targeted the Win32 API, then any GUI code will be heavily tied to Windows, and to maintain any hope of preserving your sanity, you will need to move all that code to a cross-platform GUI framework like Qt or GTK.
Under Mono, you can write a C# Winforms program that works on both platforms. But to make that possible, the Mono team had to write their own Winforms library that essentially duplicates all of the functions of Winforms. So there is still no free lunch.
Most software is portable to some extent. In the case of a C app - there will be a lot of #ifdefs in the area, apart from path changes, etc.
Rarely windows/linux version of the same software don't share a common codebase - this would actually mean that they only share a common name. It's always harder to maintain more codebases, but I think that the actual problem with porting applications has little to do with the technical side and a lot with business side. Linux has much fewer users that Windows/OSX, most of them expect everything to be free as in beer or simply hate commercial software on some religious grounds.
When you come to think about it - most open source software is multiplatform, no matter what language was used to implement it. This speaks for itself...
P.S. Disclaimer - I'm an avid supporter of Free and Open source software, I don't want to insult anybody - I just share my perspective on the topic.

For any new Win32 application development, are you foregoing .NET?

Are you choosing not to use managed code for any new applications for Win32? Why? Are there resources you need that aren't available from the CLR?
(Note "New" - not enhancements to existing codebases.)
One significant reason is ease of deployment. I can build a Win32 application (using MFC or WTL libraries), and with static linking there are no dependencies on external libraries (yes, I know that static linking is not the recommended approach).
Users can install and run this application without having to install anything else first: no framework library required, and no DLL hell. For comparison, read these posts from the author of Paint.Net to see how painful it can be for a user to install a .Net application.
I guess my last reason to write Win32 is portability. C++ compiles on all platforms, simply and without crazy dependencies. So for portable code, I still end up needing to access Win32 for the GUI.
I'm not bypassing .NET to do Win32 programming. I am bypassing both of them to do Java programming since I want my applications to run on as many platforms as possible. Windows may control a majority of the market but I don't see any reason to cut out even small possibilities for profit, especially since I can write Java code much faster than C++ or C# (that's based on my ability, not a reflection of the languages themselves).
Neither .NET not Win32 give me that cross-platform ability at the moment. They may eventually, with Mono, but I still consider that less-than-production-ready and there's still a question over its future in my mind.
At my workplace there are some old-timers who prefer using MFC because that's what they are familiar with. A few days ago we were to create a simple app and, naturally, they wanted to whip it out in MFC. Only that "whipping out" would have taken about a week and we needed the app in a day. I can't really blame them - old habits die hard. Eventually we went with C# and let the MFC-ers fiddle with the GUI design (which they much appreciated).
Yes and no. I use C++/CLI if I need to do any Win32/COM stuff. C++/CLI is wonderful. Our UIs are entirely .NET, but occasionally we do have need to use straight C++.

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