Re: Convert CGImageRef from BGR to RGB
Re: Convert CGImageRef from BGR to RGB
- Subject: Re: Convert CGImageRef from BGR to RGB
- From: Rodrigo Gutierrez <email@hidden>
- Date: Tue, 17 Jun 2008 20:48:37 -0400
Let's just say that vImage isn't an option on the platform I would
like to develop for. I was hoping there would be an approach that used
a CGColorSpaceRef and the CGImageCreateCopyWithColorSpace method. I'm
not sure if this is a valid approach though since the apple docs for
doing these types of things are fairly sparse IMHO. The Quartz 2D
Programming Guide even mentions BGR vs RGB color profiles, but doesn't
clearly say to go from one profile to another.
-rod
If you get your image data into a bitmap form you can use vImage's
(Accelerate Framework) permute functions to quickly rearrange the
channel ordering. There might be another way using color spaces, but
none that I know off hand.
On Jun 16, 2008, at 5:09 PM, Rodrigo Gutierrez wrote:
I'm pulling data off a streaming web camera, and it appears that the
camera sends jpeg data using the BGR color space. Right now I am
creating a CGImageRef by doing the following:
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL,
jpegData, jpegDataLength, NULL);
CGImageRef imageRef = CGImageCreateWithJPEGDataProvider(provider,
NULL, true, kCGRenderingIntentDefault);
Where jpegData is the payload of several packets concatenated, and
jpegDataLength is the length of the jpegData buffer... basic stuff.
This approach gets me an image but my reds and blues are flipped. I
checked out the documentation and google and I couldn't find a clear
way to swap the red and blue using Cocoa. Can someone steer me in
the right direction?
I appreciate any help.
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