Convert UIImage to CVPixelBufferRef

Question

I want to convert a UIImage object to a CVPixelBufferRef object, but I have absolutly no idea. And I can\'t find any example code doing anything like this.

Can someo

Answer 1

Google is always your friend. Searching for "CVPixelBufferRef" the first result leads to this snippet from snipplr:

- (CVPixelBufferRef)fastImageFromNSImage:(NSImage *)image{
CVPixelBufferRef buffer = NULL;

// config
size_t width = [image size].width;
size_t height = [image size].height;
size_t bitsPerComponent = 8; // *not* CGImageGetBitsPerComponent(image);
CGColorSpaceRef cs = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
CGBitmapInfo bi = kCGImageAlphaNoneSkipFirst; // *not* CGImageGetBitmapInfo(image);
NSDictionary *d = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey, [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey, nil];

// create pixel buffer
CVPixelBufferCreate(kCFAllocatorDefault, width, height, k32ARGBPixelFormat, (CFDictionaryRef)d, &buffer);
CVPixelBufferLockBaseAddress(buffer, 0);
void *rasterData = CVPixelBufferGetBaseAddress(buffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(buffer);

// context to draw in, set to pixel buffer's address
CGContextRef ctxt = CGBitmapContextCreate(rasterData, width, height, bitsPerComponent, bytesPerRow, cs, bi);
if(ctxt == NULL){
    NSLog(@"could not create context");
    return NULL;
}

// draw
NSGraphicsContext *nsctxt = [NSGraphicsContext graphicsContextWithGraphicsPort:ctxt flipped:NO];
[NSGraphicsContext saveGraphicsState];
[NSGraphicsContext setCurrentContext:nsctxt];
[image compositeToPoint:NSMakePoint(0.0, 0.0) operation:NSCompositeCopy];
[NSGraphicsContext restoreGraphicsState];

CVPixelBufferUnlockBaseAddress(buffer, 0);
CFRelease(ctxt);

return buffer;
}

No idea if this works at all, though. (Your mileage may wary :)