GNUstep slowness while drawing

[Andreas Höschler]

Hi all,

I have a view subclass with

- (void)mouseDown:(NSEvent *)theEvent
{
   NSPoint locA = [self convertPoint:[theEvent locationInWindow] 
fromView:nil];
   BOOL shiftPressed = (([theEvent modifierFlags] & NSShiftKeyMask) > 
0);
   BOOL keepOn = YES;
   BOOL hasDragged = NO;

   while (keepOn)
     {
      theEvent = [[self window] nextEventMatchingMask:NSLeftMouseUpMask 
| NSLeftMouseDraggedMask];
      switch ([theEvent type])
        {
         case NSLeftMouseDragged:
           {
              NSPoint locB = [self convertPoint:[theEvent 
locationInWindow] fromView:nil];
              NSSize offset =  NSMakeSize(locB.x - locA.x, locB.y - 
locA.y);
              NSRect oldRect = _selectionRect;
              _selectionRect.origin = locA;
              if (offset.width < 0)
                {
                 _selectionRect.origin.x = locB.x;
                 offset.width = -offset.width;
                }
              if (offset.height < 0)
                {
                 _selectionRect.origin.y = locB.y;
                 offset.height = -offset.height;
                }
              _selectionRect.size = offset;
              _selecting = YES;
              [self setNeedsDisplayInRect:NSUnionRect(_selectionRect, 
oldRect)];
              hasDragged = YES;
           }
            break;

         case NSLeftMouseUp:
           {
              keepOn = NO;
           }
            break;

         default:
            break;
        }
     }
}

- (void)drawRect:(NSRect)rect
{
   [super drawRect:rect];
   if (_selecting)
     {
      [[NSColor grayColor] set];
      NSFrameRect(_selectionRect);
     }
}

This draws a rectangle following the mouse until the user releases the 
mouse button. On MacOSX the rectangle follows the mouse instantly. 
Under GNUstep I see a significant delay. Dragging rectangles makes no 
fun there. Any idea why this is so slow? This of course has nothing to 
do with rectangles in special but with slow drawing code in general. In 
my app I want to drag objects around with the mouse. This works under 
GNUstep and MacOX but on GNustep it is almost too slow to be usable. Is 
this a known (may be even already improved) issue? My GNUstep tree is 
already a year old. :-)

Thanks,

  Andreas