drawing to NSImage off display

[Scott Christley]

Hello,

Some code which use to work is no longer working and I'm not sure why.

I use some worker threads to do computation, then they draw into their  
own personal NSImage objects, which are then passed over to the main  
GUI thread to be displayed.  It seems that the drawing into the  
NSImage is not working properly.  The method for each worker thread  
looks somewhat like this:


- doWork
{
        // do some stuff

        [image lockFocus];

        [[NSColor greenColor] set];
        NSRectFill(aRect);

        // do some more drawing

        [image unlockFocus];
}


Is there any reason why drawing into NSImage, either off display or in  
worker threads, should not work?

I verified that nothing is wrong with the rest of my code, because I  
can change that -doWork method to just load an image from a file, like  
this, and the image displays just fine:

image = [[NSImage alloc] initWithContentsOfFile: file];


On a secondary note, I tried saving the image to a file, after I - 
unlockFocus, but it produces a corrupt file.

[[image TIFFRepresentation] writeToFile: file atomically: NO];


I'm using GNUstep from SVN, on Debian with the art backend.

thanks
Scott