NSImage DPI Question

Question

Can anyone tell me how I can get the true width and height of an NSImage? I have noticed that images that are a higher DPI than 72 come through with inaccurate width and height with the NSImage.size parameters.

I saw this example on Cocoadev:

NSBitmapImageRep *rep = [image bestRepresentationForDevice: nil];

NSSize pixelSize = NSMakeSize([rep pixelsWide],[rep pixelsHigh]);

However bestRepresentationForDevice is deprecated on 10.6... what can I use as an alternative, the documentation doesn't offer a different method?

score 5 · Accepted Answer · answered Jan 20 '11 at 16:58

5

Build your NSBitmapImageRep from the TIFF representation of the NSImage

NSBitmapImageRep* rep = [NSBitmapImageRep imageRepWithData:[image TIFFRepresentation]];

answered Jan 20 '11 at 16:58

Comrade Yeti

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score 1 · Answer 2 · answered May 16 '12 at 20:27

1

Iterate through the image's representation looking for the one with the largest -size. Calling -bestRepresentationForRect:context:hints: should do this for you if you feed an extremely large rectangle.

answered May 16 '12 at 20:27

Mike Abdullah

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score 0 · Answer 3 · answered May 15 '12 at 12:36

@interface NSImage (Representation)
-(NSBitmapImageRep*)bitmapRepresentation;
@end

@implementation NSImage (Representation)
-(NSBitmapImageRep*)bitmapRepresentation {
    for (id thing in self.representations) {
        if (![thing isKindOfClass:[NSBitmapImageRep class]]) continue;
        return (NSBitmapImageRep*)thing;
    }
    return nil;
}
@end

NSImage DPI Question

3 Answers3