Re: NSBitmapImageRep bitmapData contains all zeroes?
Re: NSBitmapImageRep bitmapData contains all zeroes?
- Subject: Re: NSBitmapImageRep bitmapData contains all zeroes?
- From: Jean-Daniel Dupas <email@hidden>
- Date: Fri, 25 Apr 2008 17:49:27 +0200
What do you want to do with you captured images ? Just display them or
record them ?
If you just want to display it, you should use an NSOpenGLView and
draw the CVBuffer or the CIImage directly.
If this is for recording or processing the pixels (without CoreImage),
you can try to generate a CVPixelBuffer (using the ARGB pixel format)
instead of CVOpenGLTextureBuffer.
You can do this using QTPixelBufferContextCreate() instead of
QTOpenGLTextureContextCreate() to create your drawing context.
A CVPixelBuffer allow you to access directly to the bitmapData
(without using CIImage and NSBitmapImageRep).
You can check the QTPixelBufferVCToCGImage sample code to see how to
setup this kind of context.
Le 25 avr. 08 à 16:49, Raphael Sebbe a écrit :
Hi,
how do you "convert" CIImage to NSBitmapImageRep ?
Raphael
On Fri, Apr 25, 2008 at 4:34 PM, Nick Forge <email@hidden>
wrote:
I am working on a Computer Vision project that uses real-time image
processing. I am grabbing frames using QTKit, then converting the
resulting
CVImageBufferRef into a CIImage, and then converting that into an
NSBitmapImageRep. I know that my resulting NSBitmapImageRep is
fine, since I
am viewing it by sticking it in an NSImage and then popping that
into an
NSImageView (the QTKit Capture Preview has a 1/2 second lag time -
which is
unacceptable for this project). Everything works as it should, but
when I go
to grab the raw pixel data from the NSBitmapImageRep like so:
unsigned char *bitmapData = [self bitmapData];
(btw it says "self" because this is from a category of
NSBitmapImageRep)
The resulting array, bitmapData, is an array of zeroes! Every pixel
sample
in bitmapData is zero, yet I can draw the image and the image IS
there.
What's going on? Any suggestions as to what I may be overlooking?
Thanks in advance,
Nick Forge
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