iPhone one finger scaling gesturerecognizer

Question

I want to handle scaling and rotation of a view with one corner in that view. I found one tutorial for the rotation. https://github.com/kirbyt/KTOneFingerRotationGestureRecognizer

It makes custom UIGesturRecognizer for rotation using atan2f function. But there is nothing i could find for scaling. Can anybody tell me which is similar math function for scaling or any tutorial help for this purpose.

Any help will be appreciated.

Answer 1

-(void)oneFingerGesture:(UIPanGestureRecognizer *)recognizer { if ([recognizer state] == UIGestureRecognizerStateBegan) { //rotation deltaAngle = atan2([recognizer locationInView:holderView.superview].y-holderView.center.y, [recognizer locationInView:holderView.superview].x-holderView.center.x); startTransform = holderView.transform; //resize prevPoint = [recognizer locationInView:holderView.superview]; [holderView setNeedsDisplay];

}
else if ([recognizer state] == UIGestureRecognizerStateChanged)
{
    //rotation
    float ang = atan2([recognizer locationInView:holderView.superview].y - holderView.center.y, [recognizer locationInView:holderView.superview].x - holderView.center.x);
    float angleDiff = deltaAngle - ang;
    holderView.transform = CGAffineTransformRotate(startTransform, -angleDiff);

    //resize
    CGPoint point = [recognizer locationInView:holderView.superview];
    float wChange = 0.0, hChange = 0.0, value=0.0;

    wChange = (point.x - prevPoint.x);
    hChange = (point.y - prevPoint.y);

    CGFloat radians = atan2f(holderView.transform.b, holderView.transform.a);
    CGFloat degrees = radians * (180 / M_PI);

    if (degrees<=0 && degrees>=-90) {
        value=wChange;
    }
    else if (degrees<=-90 && degrees>=-180){
        value=-hChange;
    }
    else if (degrees<=180 && degrees>=90){
        value=-wChange;
    }
    else if (degrees<=90 && degrees>=0){
        value=hChange;
    }

    holderView.bounds = CGRectMake(holderView.bounds.origin.x, holderView.bounds.origin.y, holderView.bounds.size.width + (value), holderView.bounds.size.height + (value));
    imageview.frame = CGRectMake(12, 12, holderView.bounds.size.width-24, holderView.bounds.size.height-27);
    View_marqueRotate.frame =CGRectMake(holderView.bounds.size.width-25, holderView.bounds.size.height-25, 25, 25);
    View_marqueClose.frame = CGRectMake(0, 0, 25, 25);

    prevPoint = [recognizer locationInView:holderView.superview];
    [holderView setNeedsDisplay];


}
else if ([recognizer state] == UIGestureRecognizerStateEnded)
{
    //rotation
    deltaAngle = atan2([recognizer locationInView:holderView.superview].y-holderView.center.y, [recognizer locationInView:holderView.superview].x-holderView.center.x);
    startTransform = holderView.transform;

    //resize
    prevPoint = [recognizer locationInView:holderView.superview];
    [holderView setNeedsDisplay];

}

}