将NSImage写入文件

Question

I have an NSImage from NSImage *myImage = [[NSBitmapImageRep alloc] initWithFocusedViewRect:[outputView bounds]]; and I need to save it to a file. I havent been able to find anything about saving NSImage in any format. Has anyone done this? Is it even possible?

Thanks

Answer 1

The way you say you're making an NSImage doesn't make sense. You show how to create an NSBitmapImageRep, not an NSImage.

Before you save it to a file, you convert to NSData. There is an NSImage method to convert to TIFF data, and there is an NSBitmapImageRep method to convert to data in several formats.

Answer 2

Having an NSBitmapImageRep (as JWWalker pointed out, that code doesn't create an NSImage instance), you can ask the image rep for a CGImage version of itself, and then create a CGImageDestination to write that image to a file. This may be more efficient than obtaining a data object (which will hold the raster data in memory) and provides more options.

Answer 3

If you're creating a snapshot of an actual view (as opposed to an image that you've locked focus on), then an alternative to creating a bitmap image rep would be to ask the view for PDF data of the desired rectangle . This will be vector rather than raster (except where the view itself draws an image), which will scale more nicely to higher resolutions. You would then write that data to a file the same as you would any other data.