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Convert NSImage to CVPixelBufferRef

/ Published in: Objective C
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  1. - (CVPixelBufferRef)fastImageFromNSImage:(NSImage *)image
  2. {
  3.     CVPixelBufferRef buffer = NULL;
  4.  
  5.  
  6.     // config
  7.     size_t width = [image size].width;
  8.     size_t height = [image size].height;
  9.     size_t bitsPerComponent = 8; // *not* CGImageGetBitsPerComponent(image);
  10.     CGColorSpaceRef cs = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
  11.     CGBitmapInfo bi = kCGImageAlphaNoneSkipFirst; // *not* CGImageGetBitmapInfo(image);
  12.     NSDictionary *d = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], kCVPixelBufferCGImageCompatibilityKey, [NSNumber numberWithBool:YES], kCVPixelBufferCGBitmapContextCompatibilityKey, nil];
  13.  
  14.     // create pixel buffer
  15.     CVPixelBufferCreate(kCFAllocatorDefault, width, height, k32ARGBPixelFormat, (CFDictionaryRef)d, &buffer);
  16.     CVPixelBufferLockBaseAddress(buffer, 0);
  17.     void *rasterData = CVPixelBufferGetBaseAddress(buffer);
  18.     size_t bytesPerRow = CVPixelBufferGetBytesPerRow(buffer);
  19.  
  20.     // context to draw in, set to pixel buffer's address
  21.     CGContextRef ctxt = CGBitmapContextCreate(rasterData, width, height, bitsPerComponent, bytesPerRow, cs, bi);
  22.     if(ctxt == NULL){
  23.         NSLog(@"could not create context");
  24.         return NULL;
  25.     }
  26.  
  27.     // draw
  28.     NSGraphicsContext *nsctxt = [NSGraphicsContext graphicsContextWithGraphicsPort:ctxt flipped:NO];
  29.     [NSGraphicsContext saveGraphicsState];
  30.     [NSGraphicsContext setCurrentContext:nsctxt];
  31.     [image compositeToPoint:NSMakePoint(0.0, 0.0) operation:NSCompositeCopy];
  32.     [NSGraphicsContext restoreGraphicsState];
  33.  
  34.     CVPixelBufferUnlockBaseAddress(buffer, 0);
  35.     CFRelease(ctxt);
  36.  
  37.     return buffer;
  38. }

URL: http://lists.apple.com/archives/quartz-dev/2006/Oct/msg00096.html

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