Experiments with subpixel antialiasing of NSTextField without a background. Still not correct, text appears lighter and thinner.

subpixelAntiAliasing

-(void)drawInteriorWithFrame:(NSRect)theControlViewBounds inView:(NSView*)theControlView {
    if (!self.isEditing) {
        NSLog(@"%@ drawInteriorWithFrame:%@; inView:%@;",self, NSStringFromRect(theControlViewBounds),theControlView);
        self.isEditing = YES;
        NSTextView *theTextView = [self textDrawingObject];
        NSTextContainer *theTextContainer = [theTextView textContainer];
        NSLayoutManager *theLayoutManager = [theTextContainer layoutManager];
        NSTextStorage *theTextStorage = [theLayoutManager textStorage];
        NSRange theOldGlyphRange = NSMakeRange(0, [theLayoutManager numberOfGlyphs]);
        NSRange theOldCharacterRange = [theLayoutManager characterRangeForGlyphRange:theOldGlyphRange actualGlyphRange:nil];
        [self setUpFieldEditorAttributes:theTextView];
        [theTextStorage replaceCharactersInRange:theOldCharacterRange withAttributedString:[self attributedStringValue]];
        NSRect theCellFrame = [self titleRectForBounds:theControlViewBounds];
        [theTextView setFrame:theCellFrame];
        
        NSPoint theDrawPoint = theCellFrame.origin;
        NSRange theNewGlyphRange = NSMakeRange(0, [theLayoutManager numberOfGlyphs]);
        
        NSBitmapImageRep *theAncestorRep = nil;
        NSView *theOpaqueAncestor = self.controlView;
        while (theOpaqueAncestor != self.controlView.window.contentView) {
            theOpaqueAncestor = theOpaqueAncestor.superview;
            if (theOpaqueAncestor.isOpaque) {
                
                NSRect theAncestorRect = [self.controlView convertRect:[self.controlView visibleRect] toView:theOpaqueAncestor];
                theAncestorRep = [theOpaqueAncestor bitmapImageRepForCachingDisplayInRect:theAncestorRect];
                [theOpaqueAncestor cacheDisplayInRect:theAncestorRect toBitmapImageRep:theAncestorRep];
                
                CGSize theSize = theAncestorRect.size;
                CGColorSpaceRef colorSpace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
                CGContextRef theCurrentContext = [[NSGraphicsContext currentContext] graphicsPort];
                CGContextRef theMaskContext = CGBitmapContextCreate (NULL,theSize.width,theSize.height,8,0,colorSpace,kCGBitmapByteOrder32Host|kCGImageAlphaPremultipliedFirst);
                CGContextRef theBackgroundContext = CGBitmapContextCreate (NULL,theSize.width,theSize.height,8,0,colorSpace,kCGBitmapByteOrder32Host|kCGImageAlphaPremultipliedFirst);
                CGColorSpaceRelease(colorSpace);
                if (theMaskContext != NULL && theBackgroundContext != NULL) {
                    
                    CGRect theBounds = CGRectMake(0,0,theSize.width,theSize.height);
                    
                    [NSGraphicsContext saveGraphicsState];
                    NSGraphicsContext *theMaskGraphicsContext = [NSGraphicsContext graphicsContextWithGraphicsPort:theMaskContext flipped:self.controlView.isFlipped];
                    [NSGraphicsContext setCurrentContext:theMaskGraphicsContext];
                    CGContextSetShouldSmoothFonts(theMaskContext,YES);
                    CGContextSetAllowsAntialiasing(theMaskContext,YES);
                    CGContextSetAllowsFontSmoothing(theMaskContext,YES);
                    CGContextSetAllowsFontSubpixelPositioning(theMaskContext,YES);
                    CGContextSetAllowsFontSubpixelQuantization(theMaskContext,YES);
                    if (theOpaqueAncestor.isFlipped != self.controlView.isFlipped) {
                        NSAffineTransform *theTransform = [NSAffineTransform transform];
                        [theTransform scaleXBy:1.0 yBy:-1.0];
                        CGFloat theFlip = theAncestorRect.size.height;
                        [theTransform translateXBy:0.0 yBy:-theFlip];
                        [theTransform concat];
                    }
                   
                    [theLayoutManager drawGlyphsForGlyphRange:theNewGlyphRange atPoint:theDrawPoint];
                    
                    CGImageRef theMaskImage = CGBitmapContextCreateImage(theMaskContext);
                    CGContextDrawImage(theMaskContext, theBounds, theMaskImage);
                    
                    [NSGraphicsContext restoreGraphicsState];
                    
                    [NSGraphicsContext saveGraphicsState];
                    
                    if (theOpaqueAncestor.isFlipped != self.controlView.isFlipped) {
                        NSAffineTransform *theTransform = [NSAffineTransform transform];
                        [theTransform scaleXBy:1.0 yBy:-1.0];
                        CGFloat theFlip = theAncestorRect.size.height;
                        [theTransform translateXBy:0.0 yBy:-theFlip];
                        [theTransform concat];
                    }
                    
                    CGContextClipToMask(theCurrentContext, theBounds, theMaskImage);
                    CGContextDrawImage (theCurrentContext, CGRectMake(0,0,theAncestorRect.size.width,theAncestorRect.size.height),[theAncestorRep CGImage]);
                    
                    [NSGraphicsContext restoreGraphicsState];
                    
                    CGContextSetShouldSmoothFonts(theCurrentContext,YES);
                    CGContextSetAllowsAntialiasing(theCurrentContext,YES);
                    CGContextSetAllowsFontSmoothing(theCurrentContext,YES);
                    CGContextSetAllowsFontSubpixelPositioning(theCurrentContext,YES);
                    CGContextSetAllowsFontSubpixelQuantization(theCurrentContext,YES);

                    [theLayoutManager drawGlyphsForGlyphRange:theNewGlyphRange atPoint:theDrawPoint];
                    
                    CGImageRelease(theMaskImage);
                    CGContextRelease (theMaskContext);
                    
                    self.isEditing = NO;
                    return;
                }
            }
        }
        self.isEditing = NO;
    }
}