How to make smooth rotation of image? - iphone

Question

Currently i am using UIRotationGestureRecognizer to rotate my image and my image currently rotating smoothly.
The code which i am using is
CGFloat imageRotationDegree;
if ([gesture state] == UIGestureRecognizerStateBegan || [gesture state] == UIGestureRecognizerStateChanged)
{
[gesture view].transform = CGAffineTransformRotate([[gesture view] transform], [gesture rotation]);
[gesture setRotation:0];
imageRotationDegree=[gesture rotation];
}
NSLog(#"Rotation in Degrees: %f", imageRotationDegree);
So the problem is it is always printing rotation degree as zero.So that i am unable to save the current rotation degree.
Also if i change [gesture setRotation:0]; to some other degree then rotation is not smooth.
So How can i print different rotation degree with smooth rotation.

Answer 1

try with
CGFloat imageRotationDegree;
if ([gesture state] == UIGestureRecognizerStateBegan || [gesture state] == UIGestureRecognizerStateChanged)
{
imageRotationDegree = [gesture rotation];
[gesture view].transform = CGAffineTransformRotate([[gesture view] transform], imageRotationDegree);
[gesture setRotation:0];
}
NSLog(#"Rotation in Degrees: %f", imageRotationDegree);

Answer 2

[Export("RotateImage")]
void RotateImage (UIRotationGestureRecognizer gestureRecognizer)
{
AdjustAnchorPointForGestureRecognizer (gestureRecognizer);
if (gestureRecognizer.State == UIGestureRecognizerState.Began || gestureRecognizer.State == UIGestureRecognizerState.Changed)
{
gestureRecognizer.View.Transform *= CGAffineTransform.MakeRotation (gestureRecognizer.Rotation);
// Reset the gesture recognizer's rotation - the next callback will get a delta from the current rotation.
gestureRecognizer.Rotation = 0;
}
}
void AdjustAnchorPointForGestureRecognizer (UIGestureRecognizer gestureRecognizer)
{
if (gestureRecognizer.State == UIGestureRecognizerState.Began)
{
var image = gestureRecognizer.View;
var locationInView = gestureRecognizer.LocationInView (image);
var locationInSuperview = gestureRecognizer.LocationInView (image.Superview);
image.Layer.AnchorPoint = new PointF (locationInView.X / image.Bounds.Size.Width, locationInView.Y / image.Bounds.Size.Height);
image.Center = locationInSuperview;
}
}
[Export("RotateImage")]
void RotateImage (UIRotationGestureRecognizer gestureRecognizer)
{
AdjustAnchorPointForGestureRecognizer (gestureRecognizer);
if (gestureRecognizer.State == UIGestureRecognizerState.Began || gestureRecognizer.State == UIGestureRecognizerState.Changed)
{
gestureRecognizer.View.Transform *= CGAffineTransform.MakeRotation (gestureRecognizer.Rotation);
// Reset the gesture recognizer's rotation - the next callback will get a delta from the current rotation.
gestureRecognizer.Rotation = 0;
}
}
// Zoom the image by the current scale
[Export("ScaleImage")]
void ScaleImage (UIPinchGestureRecognizer gestureRecognizer)
{
AdjustAnchorPointForGestureRecognizer (gestureRecognizer);
if (gestureRecognizer.State == UIGestureRecognizerState.Began || gestureRecognizer.State == UIGestureRecognizerState.Changed)
{
gestureRecognizer.View.Transform *= CGAffineTransform.MakeScale (gestureRecognizer.Scale, gestureRecognizer.Scale);
// Reset the gesture recognizer's scale - the next callback will get a delta from the current scale.
gestureRecognizer.Scale = 1;
}
}
// Shift the image's center by the pan amount
[Export("PanImage")]
void PanImage (UIPanGestureRecognizer gestureRecognizer)
{
gestureRecognizer.Enabled = true;
AdjustAnchorPointForGestureRecognizer (gestureRecognizer);
var image = gestureRecognizer.View;
if (gestureRecognizer.State == UIGestureRecognizerState.Began || gestureRecognizer.State == UIGestureRecognizerState.Changed)
{
var translation = gestureRecognizer.TranslationInView (this.window);
gestureRecognizer.View.Center = new PointF (gestureRecognizer.View.Center.X + translation.X, gestureRecognizer.View.Center.Y + translation.Y);
//image.Center = new PointF (image.Center.X + translation.X, image.Center.Y + translation.Y);
// Reset the gesture recognizer's translation to {0, 0} - the next callback will get a delta from the current position.
gestureRecognizer.SetTranslation (PointF.Empty, image);
}
}