Re: How to port to GNUstep ?

[Georg Fleischmann]

Hi Richard,

> 1. 2.

Already answered


> 3.
> What will have to be done to port (parts of) the application from
> OpenSTEP to GNUstep? Will it run out of the box or do I have to
> fix things first?  Which tools are available?

If the application contains advanced PostScript code you have to rewrite these  
parts of the code.
I had to remove all pswraps and PostScript user paths from my application.
This is not a big problem, since they can be replaced by other functions and 
methods.


> 4.
> Are there applications which have been successfully ported from
> NeXTSTEP? And applications that could not be ported? I am looking
> for experiences of other people.

I have ported a constructional application (CAD/CAM app, about 200.000 LOC)  
from NextStep to Openstep to GNUstep. On my way to GNUstep I had to rewrite  
some parts of the application to replace the PostScript. My application is  
running now, but there are still a few bugs to fix in the AppKit of GNUstep.  
But that's just a question of time and absolutely doable.

The nib files can be converted to gmodel files using nib2gmodel. This is done  
a little bit easier on OpenStep 4.2 than Mac OS X, since Apple has changed the  
menu structure and the dimensions of the buttons etc.
The generated gmodel files need only few corrections by hand (or script):
- Umlauts (if any) need to be converted from Standard to ISO encoding.
- the Names of Custom Classes (if any) need to be replaced by hand


> 5.
> How can you tell when it will be easy/hard to port an application
> from NeXTSTEP to GNUstep?

If your application is using graphical elements like rotated and scaled text,  
pswraps, Type 3 Fonts, then it will be harder (Drawing or Constructional apps). 
 
Otherwise it should be quite straight foreward.

Georg