I am trying to rotate a UILabel at its center, but when it rotates it changes its position. It doesn't stick to its center. I am using following code to rotate it:
float fromAngle = atan2(m_locationBegan.y-lblText.center.y, m_locationBegan.x-lblText.center.x);
//float toAngle = atan2(_location.y-lblText.center.y, _location.x-lblText.center.x);
float toAngle = atan2(_location.y-lblText.center.y+5, _location.x-lblText.center.x+5);
float newAngle = wrapd(m_currentAngle + (toAngle - fromAngle), 0, 2*3.14);
CGAffineTransform cgaRotate = CGAffineTransformMakeRotation(newAngle);
lblText.transform = cgaRotate;
int oneInFifty = (newAngle*50)/(2*3.14);
NSLog(#"%#",[NSString stringWithFormat:#"fromAngle: %f toAngle: %f Angle: %f 1in50: %i",fromAngle, toAngle, newAngle, oneInFifty]);
Can someone please help me in stopping the center moving from it?
Take a look at this blog post.
Example: (label = UILabel)
// UIView's transform property is a CGAffineTransform.
[UIView beginAnimations:nil context:NULL]; // arguments are optional
view.transform = CGAffineTransformMakeRotation(M_PI_2);
[UIView commitAnimations];
// CALayer's transform property is a CATransform3D.
// rotate around a vector (x, y, z) = (0, 0, 1) where positive Z points
// out of the device's screen.
label.layer.transform = CATransform3DMakeRotation(M_PI_2, 0, 0, 1);
Related
I have done animation opening a page on tapping on it but now I have to change it for Pan Gesture. How should I start?
[UIView setAnimationDelegate:self];
[UIView commitAnimations];
CALayer *layer = ges.view.layer;
CATransform3D initialTransform = ges.view.layer.transform;
initialTransform.m34 = 1.0 / -1100;
layer.transform = initialTransform;
layer.anchorPoint = CGPointMake(-0.0, 0.5);
[UIView beginAnimations:#"Scale" context:nil];
[UIView setAnimationDuration:2];
[UIView setAnimationCurve: UIViewAnimationCurveEaseInOut];
CATransform3D rotationAndPerspectiveTransform = ges.view.layer.transform;
rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, -M_PI , 0 , -ges.view.bounds.size.height/2, 0);
ges.view.transform = CGAffineTransformRotate(ges.view.transform, 0);
layer.transform = rotationAndPerspectiveTransform;
[UIView setAnimationDelegate:self];
[UIView commitAnimations];
UIPanGestureRecognizer myPanGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(imagePanned:)];
[_panGesture setMaximumNumberOfTouches:1];
[yourView addGestureRecognizer:myPanGesture];
1) if you want page to turn along with the pan action as user moves the view then you have to do this way.
- (void)imagePanned:(UIPanGestureRecognizer *)iRecognizer {
CGPoint translation = [recognizer translationInView:self.view];
//Calculate transformation based on the translation value of pan gesture, this will be a tricky part
[UIView animateWithDuration:0.5 delay: 0 options: 0 animations:
^(void) {
//Apply transformation
}
completion: nil];
}
Hope this will help you.
Edit : Extended Answer
*This goes with the first idea*
You just want to rotate the view right ?
then use CATransform3D, here you will need to calculate the iAngle that we are applying to view.
iAngle = //Calculate based on translation
where translation is
CGPoint translation = [recognizer translationInView:self.view];
Then apply transformation to view
CATransform3D myTransform = CATransform3DIdentity;
myTransform.m34 = 1.0 / -500;
myTransform = CATransform3DRotate(myTransform, DEGREES_TO_RADIANS(-iAngle), 0.0f, 1.0f, 0.0f); //#define DEGREES_TO_RADIANS(d) (d * M_PI / 180)
yourView.layer.transform = myTransform;
I'll give you the math behind doing it as I don't have code right now to show. Converting finger movement to rotation value is simply a matter of setting up ratios.
For angle value (used in transform):
track_spread rotation_angle
____________ = ______________
movement_x angle = ?
angle = (rotation_angle * movement_x)/track_spread;
WHERE:
track_spread = width_of_your_view (or less e.g. 70% x width_of_your_view)
rotation_angle = the final rotation you want for your view (a constant e.g. 45 degrees)
CGPoint point = [recognizer translationInView:self];
movement_x = abs(point.x);
angle = the value (in degrees) you are interested in and will input into transform after converting to radians
If someone cant figure out and still need code snippet please leave a comment.
I want to draw polygon of different sides (4-12). What is the logic for drawing a polygon. For e.g. if user selects 6 side, it should draw a hexagon, if user enters 8 sides it should draw a octagon. I have found the following code but i also want to resize the UIView in which i am drawing a polygon so that the shape inside of the view also grows along with the view. Any body can help me please. Following is the code i am using currently but it is not positioned at the center also when i resize the view that shape moves to another position in the view.
int radius = MINIMUM(widht, height)*0.4 ;
for (int i = 0; i < _numberOFsides; i++){
CGPoint point = CGPointMake(widht/2+radius *cosf(i*2*M_PI/_numberOFsides), widht/2+radius*sinf(i*2*M_PI/_numberOFsides));
if (i==0) {
[_shapePath moveToPoint:point];
}
else{
[_shapePath addLineToPoint:point];
[_shapePath stroke];
}
}
now to resize ur UIBazierPath you can add below code,
CGRect bazierRect = CGPathGetBoundingBox(bezierpath.CGPath)
CGFloat scaleX = view.frame.size.width / bazierRect.frame.size.width;
CGFloat scaleY = view.frame.size.height / bazierRect.frame.size.height;
CGAffineTransform transform = CGAffineTransformMakeScale(scaleX, scaleY);
CGPathRef newPath = CGPathCreateCopyByTransformingPath(bezierpath.CGPath, &transform);
bezierPath.CGPath = newPath;
CFRelease(newPath);
If you want to make a regular polygon with any number of sides the following code will give you the vertices of each edge and it is easy to rescale in size and number of sides:
int n = 10; //number of edges
float j = 20; //length of each edge
float x = 130;
float y = 250;//the point 130,250 will be at the bottom of the figure
float angle = 2*M_PI;
for (int i = 0; i < n; i++) {
CGRect frame = CGRectMake(x, y, 2, 2);//put a dot on x,y
NSLog(#"%f | %f, %f", angle, x, y);
x = x + j*cosf(angle);
y = y + j*sinf(angle); //move to the next point
angle = angle - 2*M_PI/n; //update the angle
//display the dot
UIView *rect = [[UIView alloc] initWithFrame:frame];
rect.backgroundColor = [UIColor blueColor];
[self.view addSubview:rect];
}
Hope this helps. If you have any questions feel free to ask and have a great day!
~Deadly Porcupine
Hi I have a UIImageView which is part on, part off screen.
I want to rotate the view around a point off screen (the center of the view.)
How do I do this?
fullRotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation"];
fullRotationAnimation.fromValue= [NSNumber numberWithFloat:0.0f];
fullRotationAnimation.toValue = [NSNumber numberWithFloat:2 * M_PI];
fullRotationAnimation.duration = 4;
fullRotationAnimation.repeatCount = 1;
[self->greyRings.layer addAnimation:fullRotationAnimation forKey:#"360"];
I'm using that code at the moment but it just spins it around the center of the screen.
Any ideas please?
Using block animation:
- (void)rotateImageView:(UIImageView *)imageView aroundPoint:(CGPoint)point byAngle:(CGFloat)angle {
CGFloat sinA = sin(angle);
CGFloat cosA = cos(angle);
CGFloat x = point.x;
CGFloat y = point.y;
CGAffineTransform transform = CGAffineTransformMake(cosA,sinA,-sinA,cosA,x-x*cosA+y*sinA,y-x*sinA-y*cosA);
[UIView animateWithDuration:4.0 animations:^{
imageView.transform = transform;
}];
}
Note that angle is in radians, so a full rotation is 2.0*M_PI.
Maybe you have to set anchorPoint of CALayer: see Specifying a Layer’s Geometry for more detail.
//(0,0) is the left-bottom of your layer bounds
self->greyRings.layer.anchorPoint = CGPointMake(0.0f, 0.0f);
I think a negative anchorPoint should also work. So you'd better give your bounds and we can calculate for you.
I'm fooling around with Apple's ScrollViewSuite, TapToZoom app, trying to place a view on the zoomed image. Here's what I want to do: on double tap, rotate the image by pi/2, zoom it by a factor of 8, then place a subview in the scrollView on top of the transformed image.
I know the view's desired frame in the original coordinate system. So I need to transform those coordinates to the new system after the zoom...
From the ScrollViewSuite...
- (void)handleDoubleTap:(UIGestureRecognizer *)gestureRecognizer {
// double tap zooms in
float newScale = [imageScrollView zoomScale] * 8; // my custom zoom
CGRect zoomRect = [self zoomRectForScale:newScale withCenter:[gestureRecognizer locationInView:gestureRecognizer.view]];
[imageScrollView zoomToRect:zoomRect animated:YES];
[self rotateView:imageScrollView by:M_PI_2]; // then the twist
}
My rotation code...
- (void)rotateView:(UIView *)anImageView by:(CGFloat)spin {
[UIView animateWithDuration:0.5 delay: 0.0
options: UIViewAnimationOptionAllowUserInteraction
animations:^{
anImageView.transform = CGAffineTransformMakeRotation(spin);
}
completion:^(BOOL finished){}];
}
Then, after the zoom is finished, place a view at a known location in the original coordinate system. This is where I think I need some help...
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)_scale {
CGFloat coX = scrollView.contentOffset.x;
CGFloat coY = scrollView.contentOffset.y;
// try to build the forward transformation that got us here, then invert it
CGAffineTransform rotate = CGAffineTransformMakeRotation(M_PI_2);
CGAffineTransform scale = CGAffineTransformMakeScale(_scale, _scale);
// should these be negative? some confusion here.
CGAffineTransform translate = CGAffineTransformMakeTranslation(coX, coY);
// what's the right order of concatenation on these? more confusion
CGAffineTransform aft0 = CGAffineTransformConcat(rotate, scale);
CGAffineTransform aft1 = CGAffineTransformConcat(aft0, translate);
// invert it
CGAffineTransform aft = CGAffineTransformInvert(aft1);
// this is the fixed rect in original coordinate system of the image
// the image is at 0,0 320, 300 in the view, so this will only work
// when the image is at the origin... need to fix that later,too.
CGRect rect = CGRectMake(248, 40, 90, 160);
CGRect xformRect = CGRectApplyAffineTransform(rect, aft);
// build a subview with this rect
UIView *newView = [scrollView viewWithTag:888];
if (!newView) {
newView = [[UIView alloc] initWithFrame:xformRect];
newView.backgroundColor = [UIColor yellowColor];
newView.tag = 888;
[scrollView addSubview:newView];
} else {
newView.frame = xformRect;
}
// see where it landed...
NSLog(#"%f,%f %f,%f", xformRect.origin.x, xformRect.origin.y, xformRect.size.width, xformRect.size.height);
}
Dear All,
I want to rotate a UIImageView relative to a point in touchesMoved method.
I tried 2 -3 methods but I am not getting the exact result what I expected to be.
First method I used
CGAffineTransform transforms = CGAffineTransformMakeRotation(M_PI/2);
imgView.transform = transforms;
This is written in touchesMoved. So I expect a rotation for the image view in each touchesMoved.
But the rotation is occuring only once .
Second method I used was
CGAffineTransform transforms = CGAffineTransformRotate(imgView.transform, M_PI/2);
imgView.transform = transforms;
Now the result what I get is the image in Image view is continusely rotating in each move. But imageview is not rotating. What i need is to rotate the imageview not the image.
Any help will be greatly appreciated.
Thanks & Best Regards,
Rupesh R Menon
If I understood correctly you want to achieve single finger rotation on the image. If it is so you can use following functions from one of my live working project. You can use this for single image as well as multiple images. You need to modify at some extend for multiple images. Best way is extend UIImageView class and create your own class.
From touches moved call this function
[self transformImagewithTouches:touch];
Declare 1 property and synthesize as follows. (Also please declare other variables if required in below code.
#property (nonatomic) CGFloat fltRotatedAngle;
-(void)transformImagewithTouches:(UITouch *)touchLocation
{
//NSLog(#"Before %f",self.fltRotatedAngle);
CGPoint touchLocationpoint = [touchLocation locationInView:[self superview]];
CGPoint PrevioustouchLocationpoint = [touchLocation previousLocationInView:[self superview]];
CGPoint origin;
origin.x=self.center.x;
origin.y=self.center.y;
CGPoint previousDifference = [self vectorFromPoint:origin toPoint:PrevioustouchLocationpoint];
CGAffineTransform newTransform =CGAffineTransformScale(self.transform, 1, 1);
CGFloat previousRotation = atan2(previousDifference.y, previousDifference.x);
CGPoint currentDifference = [self vectorFromPoint:origin toPoint:touchLocationpoint];
CGFloat currentRotation = atan2(currentDifference.y, currentDifference.x);
CGFloat newAngle = currentRotation- previousRotation;
//Calculate Angle to Store
fltTmpAngle = fltTmpAngle+newAngle;
self.fltRotatedAngle = (fltTmpAngle*180)/M_PI;
newTransform = CGAffineTransformRotate(newTransform, newAngle);
[self animateImageView:self toPosition:newTransform];
}
-(void)animateImageView:(UIImageView *)theView toPosition:(CGAffineTransform) newTransform
{
[UIView setAnimationsEnabled:YES];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.0750];
self.transform = newTransform;
[UIView commitAnimations];
}
-(CGPoint)vectorFromPoint:(CGPoint)firstPoint toPoint:(CGPoint)secondPoint
{
CGFloat x = secondPoint.x - firstPoint.x;
CGFloat y = secondPoint.y - firstPoint.y;
CGPoint result = CGPointMake(x, y);
return result;
}
Hope it helps. If you stuck up please let me know I ll definitely help you.
Thanks for the interest shown by you in helping me.
When I used the following code I was able to rotate the image view in my desired angle.
imgView.layer.transform = CATransform3DMakeRotation(pCalculator.tangentToCornerAngle, 0, 0, 1);
where imgView is an UIImageView.
pCalculator.tangentToCornerAngle is the desired angle in which rotation has to be made.
Function is CATransform3DMakeRotation(CGFloat angle, CGFloat x, <CGFloat y, CGFloat z);
Thankyou All,
Rupesh R Menon
It's because you have rotated it by M_PI/2 and when you rotate it again it rotates it from the initial position. Use this one
CGAffineTransform transforms = CGAffineTransformConcat(imgView.transform,CGAffineTransformMakeRotation(M_PI/2));
imgView.transform = transforms;