ImageProcessing.h

//
//  ImageProcessing.h
//  MoodChanger 
//
//  Created by Austin Feight on 2/2/14.
//
//

#pragma mark-

// used for KVO observation of the @"capturingStillImage" property to perform flash bulb animation
static const NSString *AVCaptureStillImageIsCapturingStillImageContext = @"AVCaptureStillImageIsCapturingStillImageContext";

static CGFloat DegreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;};

static void ReleaseCVPixelBuffer(void *pixel, const void *data, size_t size);
static void ReleaseCVPixelBuffer(void *pixel, const void *data, size_t size)
{
	CVPixelBufferRef pixelBuffer = (CVPixelBufferRef)pixel;
	CVPixelBufferUnlockBaseAddress( pixelBuffer, 0 );
	CVPixelBufferRelease( pixelBuffer );
}

// create a CGImage with provided pixel buffer, pixel buffer must be uncompressed kCVPixelFormatType_32ARGB or kCVPixelFormatType_32BGRA
static OSStatus CreateCGImageFromCVPixelBuffer(CVPixelBufferRef pixelBuffer, CGImageRef *imageOut);
static OSStatus CreateCGImageFromCVPixelBuffer(CVPixelBufferRef pixelBuffer, CGImageRef *imageOut)
{
	OSStatus err = noErr;
	OSType sourcePixelFormat;
	size_t width, height, sourceRowBytes;
	void *sourceBaseAddr = NULL;
	CGBitmapInfo bitmapInfo;
	CGColorSpaceRef colorspace = NULL;
	CGDataProviderRef provider = NULL;
	CGImageRef image = NULL;
	
	sourcePixelFormat = CVPixelBufferGetPixelFormatType( pixelBuffer );
	if ( kCVPixelFormatType_32ARGB == sourcePixelFormat ) {
		bitmapInfo = kCGBitmapByteOrder32Big | kCGImageAlphaNoneSkipFirst;
	} else if ( kCVPixelFormatType_32BGRA == sourcePixelFormat ) {
		bitmapInfo = kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipFirst;
	} else {
		return -95014; // only uncompressed pixel formats
  }
	
	sourceRowBytes = CVPixelBufferGetBytesPerRow( pixelBuffer );
	width = CVPixelBufferGetWidth( pixelBuffer );
	height = CVPixelBufferGetHeight( pixelBuffer );
	
	CVPixelBufferLockBaseAddress( pixelBuffer, 0 );
	sourceBaseAddr = CVPixelBufferGetBaseAddress( pixelBuffer );
	
	colorspace = CGColorSpaceCreateDeviceRGB();
  
	CVPixelBufferRetain( pixelBuffer );
	provider = CGDataProviderCreateWithData( (void *)pixelBuffer, sourceBaseAddr, sourceRowBytes * height, ReleaseCVPixelBuffer);
	image = CGImageCreate(width, height, 8, 32, sourceRowBytes, colorspace, bitmapInfo, provider, NULL, true, kCGRenderingIntentDefault);
	
bail:
	if ( err && image ) {
		CGImageRelease( image );
		image = NULL;
	}
	if ( provider ) CGDataProviderRelease( provider );
	if ( colorspace ) CGColorSpaceRelease( colorspace );
	*imageOut = image;
	return err;
}

// utility used by newSquareOverlayedImageForFeatures for
static CGContextRef CreateCGBitmapContextForSize(CGSize size);
static CGContextRef CreateCGBitmapContextForSize(CGSize size)
{
  CGContextRef    context = NULL;
  CGColorSpaceRef colorSpace;
  int             bitmapBytesPerRow;
	
  bitmapBytesPerRow = (size.width * 4);
	
  colorSpace = CGColorSpaceCreateDeviceRGB();
  context = CGBitmapContextCreate (NULL,
                                   size.width,
                                   size.height,
                                   8,      // bits per component
                                   bitmapBytesPerRow,
                                   colorSpace,
                                   (CGBitmapInfo)kCGImageAlphaPremultipliedLast);
	CGContextSetAllowsAntialiasing(context, NO);
  CGColorSpaceRelease( colorSpace );
  return context;
}

#pragma mark-

@interface UIImage (RotationMethods)
- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees;
@end

@implementation UIImage (RotationMethods)

- (UIImage *)imageRotatedByDegrees:(CGFloat)degrees
{
	// calculate the size of the rotated view's containing box for our drawing space
	UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,self.size.width, self.size.height)];
	CGAffineTransform t = CGAffineTransformMakeRotation(DegreesToRadians(degrees));
	rotatedViewBox.transform = t;
	CGSize rotatedSize = rotatedViewBox.frame.size;
	
	// Create the bitmap context
	UIGraphicsBeginImageContext(rotatedSize);
	CGContextRef bitmap = UIGraphicsGetCurrentContext();
	
	// Move the origin to the middle of the image so we will rotate and scale around the center.
	CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2);
	
	//   // Rotate the image context
	CGContextRotateCTM(bitmap, DegreesToRadians(degrees));
	
	// Now, draw the rotated/scaled image into the context
	CGContextScaleCTM(bitmap, 1.0, -1.0);
	CGContextDrawImage(bitmap, CGRectMake(-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), [self CGImage]);
	
	UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
	UIGraphicsEndImageContext();
	return newImage;
	
}

@end