face detection and image placing on it - ios

Question

i am trying to detect face in UIImageview and place image on mouth.
i have tried this method, but i can't transform CoreImage Coordination system to UIkit coordination system. here is my code:
code updated but still not functioning, just rotating view
#interface ProcessImageViewController ()
#end
#implementation ProcessImageViewController
#synthesize receivedImageData;
#synthesize renderImageView;
#synthesize viewToRender;
#synthesize preview;
#synthesize pancontrol;
#synthesize pinchcontrol;
#synthesize rotatecontrol;
- (BOOL)prefersStatusBarHidden {
return YES;
}
- (void)viewDidLoad
{
[super viewDidLoad];
renderImageView.image = receivedImageData;
renderImageView.contentMode = UIViewContentModeScaleToFill;
}
-(void)tryAddCliparts
{
NSLog(#"button clicked");
[self performSelectorInBackground:#selector(markFaces:) withObject:renderImageView];
}
- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer {
CGFloat firstX = recognizer.view.center.x;
CGFloat firstY = recognizer.view.center.y;
CGPoint translationPoint = [recognizer translationInView:self.view];
CGPoint translatedPoint = CGPointMake(firstX + translationPoint.x, firstY+ translationPoint.y);
CGFloat viewW = renderImageView.frame.size.width;
CGFloat viewH = renderImageView.frame.size.height;
if (translatedPoint.x<0 || translatedPoint.x>viewW)
translatedPoint.x = renderImageView.frame.origin.x;
if (translatedPoint.y<0|| translatedPoint.y>viewH)
translatedPoint.y = renderImageView.frame.origin.y;
recognizer.view.center = CGPointMake(translatedPoint.x, translatedPoint.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
}
- (IBAction)handlePinch:(UIPinchGestureRecognizer *)recognizer {
recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale);
recognizer.scale = 1;
}
- (IBAction)handleRotate:(UIRotationGestureRecognizer *)recognizer {
recognizer.view.transform = CGAffineTransformRotate(recognizer.view.transform, recognizer.rotation);
recognizer.rotation = 0;
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
return YES;
}
-(void)markFaces:(UIImageView *)facePicture
{
NSLog(#"face detection started");
// draw a ci image from view
CIImage *image = [CIImage imageWithCGImage:facePicture.image.CGImage];
// Create face detector with high accuracy
CIDetector* detector = [CIDetector detectorOfType:CIDetectorTypeFace
context:nil options:[NSDictionary dictionaryWithObject:CIDetectorAccuracyHigh forKey:CIDetectorAccuracy]];
CGAffineTransform transform = CGAffineTransformMakeScale(1, -1);
transform = CGAffineTransformTranslate(transform,
0,-facePicture.bounds.size.height);
// Get features from the image
NSArray* features = [detector featuresInImage:image];
for(CIFaceFeature* faceFeature in features) {
// Transform CoreImage coordinates to UIKit
CGRect faceRect = CGRectApplyAffineTransform(faceFeature.bounds, transform);
UIImage *mustache = [UIImage imageNamed:#"mustacheok.png"];
UIImageView *mustacheview = [[UIImageView alloc] initWithImage:mustache];
mustacheview.contentMode = UIViewContentModeScaleAspectFill;
[mustacheview.layer setBorderColor:[[UIColor whiteColor] CGColor]];
[mustacheview.layer setBorderWidth:3];
[mustacheview addGestureRecognizer:pancontrol];
[mustacheview addGestureRecognizer:pinchcontrol];
[mustacheview addGestureRecognizer:rotatecontrol];
mustacheview.userInteractionEnabled=YES;
CGPoint mouthPos = CGPointApplyAffineTransform(faceFeature.mouthPosition, transform);
[mustacheview setFrame:CGRectMake(mouthPos.x, mouthPos.y, mustacheview.frame.size.width, mustacheview.frame.size.height)];
[viewToRender addSubview:mustacheview];
[viewToRender bringSubviewToFront:mustacheview];
}
}
#end

Answer 1

CGAffineTransform transform = CGAffineTransformMakeScale(1, -1);
transform = CGAffineTransformTranslate(transform,
0,-facePicture.bounds.size.height);
for (CIFaceFeature *faceFeature in features) {
// Transform CoreImage coordinates to UIKit
CGRect faceRect = CGRectApplyAffineTransform(faceFeature.bounds, transform);
if (faceFeature.hasMouthPosition) {
// Transform CoreImage coordinates to UIKit
CGPoint mouthPos = CGPointApplyAffineTransform(faceFeature.mouthPosition, transform);
}
}
the only thing I see wrong on your code is this:
[mustacheview setFrame:CGRectMake(mouthPos.x, mouthPos.y, mustacheview.frame.size.width, mustacheview.frame.size.height)];
you should use:
[mustacheview setCenter:mouthPos];
because the detector returns the mouth center point.

Answer 2

CoreImage uses the same coordinate system as CoreGraphics, a bottom left coordinate system, as opposed to the top left coordinate system of UIKit.
So you basically have to flip along the Y-axis (multiply with -1 and offset the height of the screen)
CGAffineTransformation flipVertical =
CGAffineTransformMake(1, 0, 0, -1, 0, self.bounds.size.height);