Extract NSImage from PDFPage with varying resolution

Question

What is the best way to get an NSImage from a PDFPage object, with variable resolution?

I have a PDF file displayed in a PDFView and I need to capture the current page and store as an NSImage. Additionally, I need to be able to vary the resolution (DPI) of the page.

With this code, the resulting image is only 595x841 for an A4 page. I need higher resolution than this (up to 300DPI):

PDFPage *page = _pdfView.currentPage;
NSData *pageData = page.dataRepresentation;
NSImage *img = [[NSImage alloc] initWithData:pageData];

Answer 1

I finally managed to sort this out:

CGFloat factor = 300/72; // Scale from 72 DPI to 300 DPI
NSImage *img; // Source image
NSSize newSize = NSMakeSize(img.size.width*factor, img.size.height*factor);
NSImage *scaledImg = [[NSImage alloc] initWithSize:newSize];
[scaledImg lockFocus];
[[NSColor whiteColor] set];
[NSBezierPath fillRect:NSMakeRect(0, 0, newSize.width, newSize.height)]; 
NSAffineTransform *transform = [NSAffineTransform transform];
[transform scaleBy:factor];
[transform concat];
[img drawAtPoint:NSZeroPoint fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
[scaledImg unlockFocus];