Re: AppKit (Win32) generals questions

[Richard Frith-Macdonald]

On 9 May 2008, at 08:28, Thierry DELHAISE wrote:

> Hi Fred and others
>
> Thx for your precisions : that help a lot !
>
> I came back with my original question and will try to precise what I  
> want to do, and how, I understood, I must do the job with gnustep to  
> fit in the Framework.
>
> I want to use the low level GetOpenFileName on Windows. This  
> function take a big C structure to allow it to get all informations  
> to configure the dialog box and the feature that will be display to  
> user to allow him/her to choose a file name.
>
> So in GNUstep way, I use NSOpenPanel, later the theme Framework  
> detect that this is a NSOpenPanel and the theme Framework call the  
> appropriate (and specifique win32) DisplayServer (win32) code whitch  
> call the OS GetOpenFileName. Does it is the trick ?
>
> The scheme should be the same for PrintDialog, Color dialog, Fonts  
> dialog, etc....

Well, when adding this sort of functionality you would first need to  
decide whether you want to use these high level win32 functions at  
all ... Just using the existing code in the gui (and perhaps modifying  
it slightly) might be better in some/all cases: you would need to see  
what benefit is provided.  The thing about using native controls in  
their entirety is that this involves changing the way things operate  
(the feel), not just their appearance, and one of the reasons for  
using GNUstep is that you believe the interface is better than  
alternatives such as ms-windows, so you want to be sure that the  
benefits of using the native controls outweigh the costs. Wherever  
there is any doubt, you would probably want your theme code to allow  
the user to use NSUserdefaults or some other mechanism to select  
whether they want the native control to be used or not.  Currently the  
theme engine does not allow the entire functionality of these panels  
to be replaced (it's focussed on allowing you to draw controls in a  
themed way ... ie changing the appearance while maintaining the  
NeXTstep feel), but there's no reason that this capability can't be  
added.

>  Second question to all : where is the code for Theme Framework,  
> does it is available in trunk,(gui ?) and how does it get called (I  
> took a quick look yesterday at the NSWindow.m code and saw nothing  
> about theme, but I m certainly wrong ...

It's GSTheme in the gui library.  Currently only the bare bones are  
available, and most of the gui does not use it to draw (other than to  
determine the colors used to draw everything).  What it allows you to  
do is dynamically change the current theme, with alternative color  
settings, alternative images, and other interface style settings, plus  
providing drawing methods which can let you draw controls by tiling  
theme specific image, or use alternative code from your subclass of  
GSTheme to draw the images.

See 
http://www.gnustep.org/resources/documentation/Developer/Gui/Additions/index.html
and also http://svn.gna.org/viewcvs/gnustep/apps/thematic/trunk/