Hello!

I'm writing a QuickLook plugin. Well, everything works. Just want to try it make better ;). Thus the question.
Here is a function that returns thumbnail image and that I'm using now.

QLThumbnailRequestSetImageWithData(
QLThumbnailRequestRef thumbnail,
CFDataRef data,
CFDictionaryRef properties);
);

http://developer.apple.com/mac/library/documentation/UserExperience/Reference/QLThumbnailRequest_Ref/Reference/reference.html#//apple_ref/c/func/QLThumbnailRequestSetImageWithData

Right now I'm creating a TIFF -> encapsulated it into NSData. An example

// Setting CFDataRef
CGSize thumbnailMaxSize = QLThumbnailRequestGetMaximumSize(thumbnail);
NSMutableAttributedString *attributedString = [[[NSMutableAttributedString alloc] 
                                                   initWithString:@"dummy" 
                                                   attributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                                               [NSFont fontWithName:@"Monaco" size:10], NSFontAttributeName, 
                                                               [NSColor colorWithCalibratedRed:0.0 green:0.0 blue:0.0 alpha:1.0], NSForegroundColorAttributeName, 
                                                               nil]
                                                   ] autorelease];
NSImage *thumbnailImage = [[[NSImage alloc] initWithSize:NSMakeSize(thumbnailMaxSize.width, thumbnailMaxSize.height)] autorelease];
[thumbnailImage lockFocus];
[[NSColor whiteColor] set];
NSRectFill(NSMakeRect(0, 0, thumbnailMaxSize.width, thumbnailMaxSize.height));
[attributedString drawInRect:NSMakeRect(0, 0, thumbnailMaxSize.width, thumbnailMaxSize.height)];
[thumbnailImage unlockFocus];
(CFDataRef)[thumbnailImage TIFFRepresentation]; // This is data

// Setting CFDictionaryRef
(CFDictionaryRef)[NSDictionary dictionaryWithObjectsAndKeys:@"kUTTypeTIFF", (NSString *)kCGImageSourceTypeIdentifierHint, nil ]; // this is properties

However QuickLook provides another function to return thumbnail image, namely

QLThumbnailRequestSetImage(
QLThumbnailRequestRef thumbnail,
CGImageRef image,
CFDictionaryRef properties);

);

http://developer.apple.com/mac/library/documentation/UserExperience/Reference/QLThumbnailRequest_Ref/Reference/reference.html#//apple_ref/c/func/QLThumbnailRequestSetImage

I have a feeling that passing CGImage to the QL instead of TIFF data would help in speeding things up. However- I have never worked with CG context before. I know, the documentation is there :), but anyways- could anyone give an example how to turn that NSAttributed string into CGImageRef. An example is worth 10 times reading the documentation ;)
Any help appreciated. Thanks in advance!