On Aug 5, 2010, at 1:15 PM, Quincey Morris wrote: > On Aug 5, 2010, at 08:45, Brian Postow wrote: > >> Given a bunch of bitmap data, and a resolution, how do I create an NSImage >> (or CGImage or CGImageSource) with the correct resolution? >> >> Currently, I'm doing: >> >> CGDataProviderRef provider= CGDataProviderCreateWithData(NULL, >> (UInt8*)data, bytesPerRow * length, NULL); >> >> [...] >> >> NSData* imgData = [NSMutableData data]; >> CGImageDestinationRef dest = CGImageDestinationCreateWithData >> (imgData, kUTTypeTIFF, 1, NULL); >> CGImageDestinationAddImage(dest, cgImg, NULL); >> CGImageDestinationFinalize(dest); >> NSImage* img = [[NSImage alloc] initWithData: imgData]; >> >> >> now, it appears that CGImageDestination takes only a NULL argument for the >> dictionary.. and width and length are in pixels, not points or inches. At >> what point in this process am I supposed to add the resolution into this >> process? > > Yes, the CGImage has no resolution, only a pixel size. So you add in the > resolution at the very end, after creating the NSImage: > > img.size = NSMakeSize (widthInPoints, heightInPoints); >
oh, so size is in points? I assumed it was in pixels. The documentation just says "the size of the receiver" which my boss assumed was in pounds B-) > where the dimensions in points are computed from the pixel dimensions and the > known resolution. > > Actually, after looking at the documentation again, doing it exactly this way > seems slightly risky (if the NSImage is set to do scaling automatically, for > example). I think what you really should do is to create a NSImageRep from > the CGImage, the set the NSImageRep 'size' property to the correct size in > points, then add that image rep to a new "empty" NSImage. > > > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/cocoa-dev/brian.postow%40acordex.com > > This email sent to brian.pos...@acordex.com > Brian Postow Senior Software Engineer Acordex Imaging Systems _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
