Re: GNUstep vs. The Cocotron for Mac to Windows porting

[Dr. Rolf Jansen]

Gregory,

Thank you very much for taking your time to respond to my questions. I 
definitely need to give GNUstep a try, and I guess, the Christmas holidays are 
a perfect time to start with this. I added some comments/questions within the 
lines below:

> Am 13.12.2015 um 14:53 schrieb Gregory Casamento <greg.casamento@gmail.com>:
> 
> Dr Jansen,
> 
> See my responses below....
> 
> On Sun, Dec 13, 2015 at 7:46 AM, Dr. Rolf Jansen <rj@obsigna.com> wrote:
>> I am a Mac developer and in the past I successfully used The Cocotron to 
>> port, build and distribute one of my bigger GUI application projects for 
>> Windows. This one is feature complete now, and I am now looking forward to 
>> port one of my next big projects to Windows. I am considering to use GNUstep 
>> for this, however, I got some questions:
>> 
>> 
>> 1. Look & Feel
>> 
>> I want my applications look & feel native on Windows, and I am demanding on 
>> that. I read, that the WinUXTheme is still under development, and my 
>> question is now what exactly does this mean. Do most of the GUI elements 
>> work and look nice? Or, perhaps, do only the buttons look nice and the other 
>> stuff looks and feels somehow? What is missing? Does it crash any now and 
>> then? For my other application, I submitted some contributions to The 
>> Cocotron in order to letting it behave and look good on Windows.
> 
> GNUstep uses the native theming capabilities of Windows itself to
> blend in.  The WinUXTheme delegates to Windows to draw the widgets so
> they look entirely native.  Nothing major is missing.   The buttons,
> the menus and everything are done this way.

This is perfect for me, and I will be ready to fix minor things and contribute 
my patches to the GNUstep project.

>> 2. Interface Builder compatibility
>> 
>> Can I use my .xib-files (Deployment target OS X 10.6) without any changes 
>> for building Windows applications? With The Cocotron I can.
> 
> As long as they generate nib files you can.  The trick here is that
> Cocotron doesn't support XIB files either.  They use the nibs which
> are converted during the build process and read those.   Just like
> Cocotron, GNUstep can read the nib files, but we can't directly read
> the XIBs.  You will need to manually convert those using the ibtool on
> your mac.  I am currently working on native xib support in GNUstep so
> that no compilation of the xibs is needed.

Sorry, I meant it in the way of utilizing the compiled XIB files. my Mac 
applications do it, my Windows-Cocotron application does it, and I am perfectly 
happy once my Windows-GNUstep application would do it as well. So, I don't need 
native xib support in GNUstep, I would always ship my application with the 
compiled XIB files.

>> 3. Shared Code Base
>> 
>> My other GUI application got apprx. 25000 lines of custom Objective-C and C 
>> code, and it is a shared code base for both platforms Mac OS X and Windows. 
>> With a little bit of coding discipline, I was able to keep the number of 
>> platform specific #ifdef segments low (perhaps 5 small snippets). Can I 
>> expect the same with GNUstep for my still to be ported application (apprx. 
>> 50000 lines, other purpose, same coding style).
> 
> Yes, you can expect the same.  There are a number of apps on the
> market currently using GNUstep.  See http://www.testplant.com for an
> example of one such app.
> 
>> 4. PDF readiness
>> 
>> My application requires reading and flawless display of PDF files, as well 
>> as generation of PDF files from its view contents, some of which may become 
>> really huge. Does this work with GNUstep on Windows?
> 
> GNUstep has the capability to read and display PDFs on both Linux and Windows.

What about PDF generation using -[NSView dataWithPDFInsideRect:]?

>> 5. RTF views and editing
>> 
>> Does GNUstep provide complete RTF compatibility, editing and display. Here 
>> The Cocotron is lacking, and the application to be ported to Windows does 
>> rely heavily on perfect RTF text formatting capabilities. So actually, my 
>> concerns may be rephrased to, whether it would be more work for me to 
>> implement the missing RTF capabilities into The Cocotron, compared to 
>> implement something into GNUstep if not to work around any other 
>> shortcomings in GNUstep.
> 
> Yes, GNUstep provides complete support for RTF.  I believe it would be
> much more work to implement the capabilities you need for RTF support
> into The Cocotron.

That was my hope, and as said above I definitely will give it a try.

>> 6. License question
>> 
>> I read that it is best to ship my application with the GNUstep frameworks in 
>> separate .dll files, so end users may replace the frameworks by their 
>> customized ones. Is this correct? In addition, I must not prohibit reverse 
>> engineering of my application interface to GNUstep. As a matter of fact, my 
>> EULA's do not mention anything about reverse engineering, would this be OK, 
>> or do I need to positively permit reverse engineering?
> 
> It is possible to build an app using a "standalone" process.   This
> means that once compilation is done all of the relevant .DLLs will be
> copied into place.   This still allows you to replace them.   GNUstep
> doesn't like anything statically so it's entirely possible to upgrade
> an individual DLL within the application directory.

Please can you point me to instructions how to set up a build environment, 
ideally directed to Mac developers who want to cross build for other platforms. 
I build my Windows-Cocotron application from within the same Xcode project as 
the Mac counterpart, I only select the other target. I guess, I need to set up 
a GNUstep build environment on a Windows machine and I would drag-in my sources 
from my local SVN repository. Can I use LLVM/clang together with the 
Objective-C runtime of David Chisnall on Windows? Is LLDB working with this on 
Windows?

>> If I need to change something within GNUstep, then my intention is to commit 
>> my changes upstream, and ideally the GNUstep frameworks shipped with my 
>> application would be based on the upstream code at the given point in time. 
>> This is how, I handled it with The Cocotron. May I expect the same with 
>> GNUstep? Do I need to provide the sources in a separate place anyway, or may 
>> I simply add a link to the GNUstep SVN repository on a prominent place (e.g. 
>> the About panel) of my application?
> 
> You may expect the same with GNUstep.   The best way to go about it is
> to provide patches back to us or to sign a copyright assignment for
> your changes and commit them on a branch in the SVN repo for review
> and inclusion.

When I run into issues, then let's talk about the best way of resolving it.

>> Anything else to obey with?
> 
> Not that I am aware of.  If you have additional questions please let us know.

Best regards

Rolf