Re: NSImage -- getting raw bitmap data
Re: NSImage -- getting raw bitmap data
- Subject: Re: NSImage -- getting raw bitmap data
- From: "Dennis C.De Mars" <email@hidden>
- Date: Sat, 2 Aug 2003 10:32:44 -0700
Yes, the documentation on images seems to be terse in several respects.
The key to getting the raw pixel data on an image seems to be
-TIFFRepresentation (which, despite its name, returns an NSData object,
not an NSImageRep object). I think the most direct way to create a
bitmap from an image is probably:
NSData* tiffData = [theImage TIFFRepresentation];
NSBitmapImageRep* bitMapRep = [NSBitmapImageRep
imageRepWith
Data:tiffData];
(Assuming imageRepWithData: accepts data in TIFF format; this is one of
those areas where the documentation is terse but I'm 99% sure this will
work).
This doesn't totally address your problem because it doesn't let you
force the depth, etc., all of that is predetermined in the TIFF
representation. NSImageRep has some interesting methods for setting
these parameters but I don't know if using them on a bitmap rep will
cause any kind of conversion to take place. You could experiment.
Of course, since you have the raw pixels at this point you could do any
conversion of depth, colorspace, etc. by brute force, but it obviously
would be a lot more convenient if you could get Cocoa to do it for you.
I guess I would have tried to do it the way you tried (drawing the
image into a preformed bitmapimagerep). Don't know why that didn't
work, but if you could post some code maybe we could suggest
modifications.
- Dennis D.
On Saturday, August 2, 2003, at 07:49 AM, Uli Kusterer wrote:
Hi,
I'm using NSBitmapImageRep's initWithBitmapDataPlanes: to get some
raw bitmap data into an NSImageView. Now, I've set this view to be
editable, and users can drag image files onto it to replace the data.
But how do I get the raw image data from whatever image the user
dragged onto my NSImageView? Basically, I'd need the reverse operation
of initWithBitmapDataPlanes:, but I need to force the image to be a
particular depth, number of planes etc.
Apple's "Drawing Images" docs are pretty terse on that topic, and
Mamasam only brought up a sample by Marco Binder that was close but no
cookie, even less on cocoadevcentral. I also tried to lockFocus on the
NSBitmapImageRep and just draw the image in there, but that didn't
change the data I passed in.
Help?
Thanks for any hints and clues,
-- M. Uli Kusterer
http://www.zathras.de
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