Change view layer's size and view's position - ios

I am working with Apple's AVCam example and I am trying to modify the layout to work with the iPad.
I'm trying to get the status bar to be present throughout, however whenever I enable it, (what I believe to be the videoPreviewView and its viewLayer) are in the status bar's way. So I need to move this down by 20px to make room for the status bar but I'm not sure how.
AVCaptureVideoPreviewLayer *newCaptureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:[[self captureManager] session]];
UIView *view = [self videoPreviewView];
CALayer *viewLayer = [view layer];
[viewLayer setMasksToBounds:YES];
CGRect bounds = [videoPreviewView bounds];
[[self view] setBounds:bounds];
newCaptureVideoPreviewLayer.bounds = bounds;
[newCaptureVideoPreviewLayer setFrame:bounds];

Put this under UIView *view = [self videoPreviewView];
CGPoint viewCenter = view.center;
viewCenter = CGPointMake(viewCenter.x, viewCenter.y - 20)
view.center = viewCenter;

Adding this to to AdamG's answer did the trick, don't know why or if it is a viable solution. Anyone care to chime in?
CGPoint viewCenter = view.center;
viewCenter = CGPointMake(viewCenter.x, viewCenter.y + 20);
view.center = viewCenter;
CGRect temp = view.frame;
temp.size.height += -20;
view.frame = temp;

Related

How to convert frame from UIScrollView to UIView

I want to convert frame from UIScrollView to UIView, but not exaclty.
This is my code:
//Create UIScrollView addSubview self.view
scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
[scrollView setBouncesZoom:YES];
[scrollView setMinimumZoomScale:1];
[scrollView setZoomScale:4];
scrollView.delegate = self;
//create UIView overlay UIScrollView and addSubview self.view
overlayView = [[UIView alloc] initWithFrame:self.view.bounds];
overlayView.backgroundColor = [UIColor blueColor];
overlayView.alpha = 0.5;
[self.view addSubview:overlayView];
//create UIView addSubView overlayView, can move change postion
UIView *moveView = [[UIView alloc] initWithFrame:CGRectMake(10, 10, 100, 100)];
moveView.backgroundColor = [UIColor redColor];
[overlayView addSubView:moveView];
If zoom in, zoom out scrollView, moveView change position by ratio when scrollView zoom in zoom out.
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale {
[scrollView setZoomScale:scale+0.01 animated:NO];
[scrollView setZoomScale:scale animated:NO];
CGRect visibleRect;
visibleRect.origin = scrollView.contentOffset;
visibleRect.size = CGSizeMake(scrollView.bounds.size.width * scrollView.zoomScale, scrollView.bounds.size.height * scrollView.zoomScale);
visibleRect.origin.x = 0;
visibleRect.origin.y = 0;
overlay.frame = visibleRect;
CGRect moveRect = moveView.frame;
moveRect.origin.x *= scrollView.zoomScale;
moveRect.origin.y *= scrollView.zoomScale;
moveRect.size.width *= scrollView.zoomScale;
moveRect.size.height *= scrollView.zoomScale;
moveView.frame = moveRect;
}
I cannot change postion moveView exactly when scrollView zoom in zoom out. Please help me resolve this issue.
First I'd say, you really need to be using autolayout for all this stuff. Or none of this will work if you rotate the device, or on different devices, etc. Just using frames to position views is just not the done way anymore. It will work to a degree though. Yes autolayout is a learning curve but you just need to know it and use it all the time.
But looking at the code there two issues stand out : at the start of the didEndZooming method, you set the scale twice, Im not sure why -
[scrollView setZoomScale:scale+0.01 animated:NO];
[scrollView setZoomScale:scale animated:NO];
Then also later, you set the origin of the visibleRect property twice in different ways :
visibleRect.origin = scrollView.contentOffset;
visibleRect.size = CGSizeMake(scrollView.bounds.size.width * scrollView.zoomScale, scrollView.bounds.size.height * scrollView.zoomScale);
visibleRect.origin.x = 0;
visibleRect.origin.y = 0;
Setting the x and y values there is the same as setting the origin to the scrollView.contentOffset - so first you set the origin to the content offset position, then to 0,0 - which doesnt make sense. Clearing up those problems might sort things out.

How to find the center of a UIView after superviews have been transformed?

NOTE: code written in browser; probably not perfectly accurate, but it should give the general idea.
I've got a stack of views, something like this:
CGRect theFrame = CGRectMake(0, 0, 10, 10);
UIView *v1 = [UIView alloc] initWithFrame: theFrame];
UIView *v2 = [UIView alloc] initWithFrame: theFrame];
UIView *v3 = [UIView alloc] initWithFrame: theFrame];
// Set all the background colors, so I can see them: snip
// set all the clipsToBounds = NO, so I can place however I want: snip
v2.center = CGPointMake(100, 80);
[v1 addSubview: v2];
v3.center = CGPointMake (57, 42);
[v2 addSubview: v3];
v1.center = CGPointMake (193, 44);
[self.view addSubview: v1];
// etc., time passes, user presses TEST button
CGAffineTransform sXfrm = CGAffineTransformMakeScale(3.5, 4.7);
CGAffineTransform rXfrm = CGAffineTransformMakeRotation(M_PI / 3.);
v1.transform = CGAffineTransformConcat(sXfrm, rXfrm);
// etc., rotate & scale v2, while we're at it. snip
// Leave v3 unrotated & unscaled.
Ok, at this point, everything is displaying on the screen exactly as desired. My question is:
Where (that is: where, in self.view's coordinate space) is v3.center?
Here's some code that gives the CLOSE answer, but not-quite right, and I can't seem to figure out what's wrong with it:
CGRect testRect = CGRectMake(0, 0, 20, 20);
UIView *testView = [[UIView alloc] initWithFrame: testRect];
testView.backgroundColor = [UIColor greebColor];
[self.view addSubview: testView];
CGPoint center = v1.center;
#if 1 // Apply Transform
CGPoint ctr2 = CGPointApplyAffineTransform(v2.center, v1.transform);
#else // use layer
CGPoint ctr2 = CGPointMake ((v2.layer.frame.origin.x + (v2.layer.frame.size.width / 2.)),
(v2.layer.frame.origin.y + (v2.layer.frame.size.height / 2.)) );
ctr2 = CGPointApplyAffineTransform(ctr2, v1.transform);
#endif
center.x += ctr2.x;
center.y += ctr2.y;
CGPoint ctr3 = CGPointApplyAffineTransform(v3.center, CGAffineTransformConcat(v2.transform, v1.transform));
center.x += ctr3.x;
center.y += ctr3.y;
testView.center = center; // I want this to lay on top of v3
[self.view addSubview: testView];
NOTE: In my actual code, I put in-between test-views at all the intermediate centers. What I get is: testView1 (center) is correct, testView2 (ctr2) is off by a little, testView3 (ctr3) is off by a little more.
The #if is because I was experimenting with using ApplyAffine vs layer. Turns out they both give the same result, but it's a tad off.
Hopefully clarifying image:
You can use the UIView's convert points methods:
convertPoint:toView:
convertPoint:fromView:
convertRect:toView:
convertRect:fromView:
However once you apply a transformation, you should stop using frames and use center + bounds instead (which might be the reason your code is not working), from apple docs (for frame):
Warning: If the transform property is not the identity transform, the
value of this property is undefined and therefore should be ignored.
The only other thing you have to be conscious about is, which view invoques the convert to what other view since the results change. (source coordinate system -> target coordinate system.)
EDIT:
Thanks to this answer and Chiquis' comments in the question, my (Olie's) final (working) code looks like this:
CGRect testRect = CGRectMake(0, 0, 20, 20);
UIView *testView[3];
for (int ii = 0 ; ii < 3 ; ++ii)
{
testView[ii] = [[UIView alloc] initWithFrame: testRect];
testView[ii].backgroundColor = [UIColor redColor];
[self.view addSubview: testView[ii]];
}
testView[0].center = v0.center;
testView[1].center = [v0 convertPoint: v1.center toView: self.view];
testView[2].center = [v1 convertPoint: v2.center toView: self.view];
To clarify some, v1 is a subview of v0, and v2 is a subview of v1; this dictates the receivers in the covertPoint: calls.
I try to let iOS do the heavy lifting for me when I need to transform points between different layers.
CGPoint point = v3.center;
CGPoint ctr3 = [v3.layer.presentationLayer convertPoint:point toLayer:self.layer.presentationLayer];
The presentation layer object represents the state of the layer as it currently appears onscreen. This can help avoid timing issues if animations are involved.
Just noticed the comment that came in while I was composing: yes, I use this to account for rotation transforms similar to what you describe.

UIPanGestureRecognizer on a UIView behaves oddly after UIViews layer is animated

I have a series of UIViews which I animate along an arc. Each view has a UIPanGestureRecognizer on it which before any animation occurs works as expected.
However after animating the views (with the method below which animates a view's layer) the gestures do not work as expected; in fact it appears as if they work in their original screen positions.
I've tried various things including matching up the views frame and/ or bounds with that on the animated layer and even removing the existing gestures and creating and adding them again (not shown below).
If anyone knows what's going on or can get me on the road to fixing the issue it would be greatly appreciated.
EDIT: iMartin's suggestion to change
pathAnimation.removedOnCompletion = NO;
to
pathAnimation.removedOnCompletion = YES;
and
view.layer.position = ... //
have put me on the way to fixing the issue.
Original Code:
- (void)animateUIViewAlongArc:(UIView*)view clockwise:(BOOL)clockwise duration:(float)duration
{
[UIView animateWithDuration:duration animations:^{
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimationanimationWithKeyPath:#"position"];
pathAnimation.calculationMode = kCAAnimationPaced;
pathAnimation.fillMode = kCAFillModeForwards;
pathAnimation.removedOnCompletion = NO;
pathAnimation.repeatCount = 1;
CGPoint viewCenter = view.objectCenter;
CGMutablePathRef arcPath = CGPathCreateMutable();
CGPathMoveToPoint(arcPath, NULL, viewCenter.x, viewCenter.y);
float angleOfRotation = self.angleIncrement;
if (clockwise == NO)
{
angleOfRotation *= -1.0f;
}
float fullwayAngle = view.angle + angleOfRotation;
CGPoint fullwayPoint = pointOnCircle(self.center, self.radius, fullwayAngle);
CGPathAddRelativeArc(arcPath, NULL, self.center.x, self.center.y, self.radius, view.angle, angleOfRotation);
pathAnimation.path = arcPath;
CGPathRelease(arcPath);
[view.layer addAnimation:pathAnimation forKey:#"arc"];
view.angle = fullwayAngle;
view.objectCenter = fullwayPoint;
} completion:^(BOOL finished){
if (finished)
{
CGRect frame = view.layer.frame;
CGRect bounds = view.layer.bounds;
view.frame = frame;
view.bounds = bounds;
}
}];
}
Did you check the frame of the view/layer after the animation?
I think the problem is, that what you see is not what you get. The layer itself didn't changes its position/frame, but just its presentationLayer did. Presentation layer is what you actualy see onthe screen. You could see this if you remove this line:
pathAnimation.removedOnCompletion = NO; // Delete or set to YES
Setting this to NO caused the presentation layer to be on screen at different position than your view.
What you should do, is to set final position to the layer just before adding the animation to it.
view.layer.position = finalPosition; // You should calculate this
[view.layer addAnimation:pathAnimation forKey:#"arc"];

When I make zoom center is shifted to the left bottom

I'm developing an iOS application with latest SDK.
I'm working with camera and I want to make zoom. To do it I have this code:
- (void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self setUpVideo];
}
- (void)setUpVideo
{
NSLog(#"Set up video");
UIView *view = [self videoPreviewView];
CALayer *viewLayer = [view layer];
[viewLayer setMasksToBounds:YES];
AVCaptureVideoPreviewLayer *newCaptureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:DataExchanger.cameraManager.captureSession];
CGRect bounds = [view bounds];
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
CGAffineTransform t;
if (orientation == UIInterfaceOrientationLandscapeRight)
{
t = CGAffineTransformMakeRotation(-M_PI_2);
bounds = CGRectMake(bounds.origin.x, bounds.origin.y,
bounds.size.height, bounds.size.width);
}
[newCaptureVideoPreviewLayer setFrame:bounds];
[newCaptureVideoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
newCaptureVideoPreviewLayer.position = CGPointMake(CGRectGetMidX(bounds), CGRectGetMidY(bounds));
newCaptureVideoPreviewLayer.affineTransform = t;
[viewLayer insertSublayer:newCaptureVideoPreviewLayer below:[[viewLayer sublayers] objectAtIndex:0]];
CGAffineTransform currentTransform = CGAffineTransformIdentity;
CGAffineTransform newTransform = CGAffineTransformScale(currentTransform, 2.0f, 2.0f);
view.transform = newTransform;
}
But I see a different between the zoom image and the same image without zoom. Without moving the camera I see that the center shifted to the left bottom when I made zoom.
Maybe I have to move videoView centers with a formula that calculates its new center using the scale.
Do you know how to fix that?

Animate UIView height from bottom to top

I'm doing a simple animation of UIView height so that it reveals.
By default it seems to be revealing from top to bottom, and I want it to reveal bottom to top.
I have the UIView anchored to the bottom of the screen.
I'm sure it something simple i'm missing..... any tips?
Thanks
I really think the simplest way to accomplish this would be to animate BOTH the height and the y properties of the view. If they happen along the same curve, it should look completely seamless to the user. As you are animating the height to 0, also animate the y component to the original y + the original height.
UIView *view = ...;
float originalY = view.frame.origin.y;
float originalH = view.bounds.size.height;
[UIView animateWithDuration:1.2f delay:1.0f options:UIViewAnimationCurveEaseInOut animations:^{
view.frame = CGRectMake(view.frame.origin.x, (originalY + originalH), view.bounds.size.width, 0);
}completion:^(BOOL finished) {
NSLog(#"Animation is complete");
}];
I believe this would give the look and feel of a collapsing view. I haven't tried this out in code, but I see no reason why it wouldn't be possible like this.
hide under bottom
[self animateViewHeight:myView withAnimationType:kCATransitionFromBottom];
for reverse animation
[self animateViewHeight:myView withAnimationType:kCATransitionFromTop];
...
- (void)animateViewHeight:(UIView*)animateView withAnimationType:(NSString*)animType {
CATransition *animation = [CATransition animation];
[animation setType:kCATransitionPush];
[animation setSubtype:animType];
[animation setDuration:0.5];
[animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
[[animateView layer] addAnimation:animation forKey:kCATransition];
animateView.hidden = !animateView.hidden;
}
Like a dog with a bone I figured this out....
Instead of animating the frame height, I applied a transform to the view and set the anchor point of the layer.
//set the anchor point to the bottom of the view
[self setAnchorPoint:CGPointMake(0.5, 1.0) forView:hostView];
//Scale the height to close to zero
hostView.transform = CGAffineTransformMakeScale(1, 0.00001);
If I put 0 as the y scale, the view behaves weird.... at the end of the animation i just set it to hidden.
On the way back up I just use the Identity Transform (reset it)
hostView.transform = CGAffineTransformIdentity;
Note that changing my anchor point shifted the position of my view. See this post for the setAnchorPoint method which normalises the view after setting the anchorPoint
Changing my CALayer's anchorPoint moves the view
Instead you could try putting it in a view with clipsToBounds = YES and then animate it from the bottom to the middle of the view, like so:
viewToAnimate.frame = CGRectMake(viewToAnimate.frame.origin.x,
viewToAnimate.superview.frame.size.height,
viewToAnimate.frame.size.width,
viewToAnimate.frame.size.height);
[UIView animateWithDuration:0.5 animations:^{
viewToAnimate.center = viewToAnimate.superview.center;
}];
This way, you don't have to set the height to 0, and it solves any problems with autoresizing within the view.
As requested, this is the code that I'm using... I'm using a CAKeyFrameAnimation, which may be a bit more than what you're looking for. It would probably work the same with a CABasicAnimation, I'm just showing you this code because I already have it written.
-(id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
springLayer = [[CALayer alloc] init];
springLayer.backgroundColor = [UIColor redColor].CGColor;
springLayer.anchorPoint = CGPointMake(0, 1);
springLayer.frame = CGRectMake(125, 285, 100, 115);
[springLayer setNeedsDisplay];
[self.layer addSublayer:springLayer];
[self test];
}
return self;
}
-(void)test {
CAKeyframeAnimation *heightAnim = [[CAKeyframeAnimation alloc] init];
heightAnim.duration = 3;
heightAnim.removedOnCompletion = NO;
heightAnim.fillMode = kCAFillModeForwards;
heightAnim.beginTime = CACurrentMediaTime() + 0.25;
NSMutableArray *v = [[NSMutableArray alloc] init];
NSMutableArray *t = [[NSMutableArray alloc] init];
float dest = 250;
float difference = 135;
while (difference > 1.0) {
[v addObject:[NSNumber numberWithFloat:dest-difference]];
[t addObject:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut]];
difference *= 0.7;
[v addObject:[NSNumber numberWithFloat:dest+difference]];
[t addObject:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut]];
difference *= 0.7;
}
heightAnim.values = v;
heightAnim.timingFunctions = t;
[springLayer addAnimation:heightAnim forKey:#"bounds.size.height"];
}
one way I've done it with an AdWhirlView, hide it below the screen, then animate it up;
AdWhirlView *adWhirlView = [AdWhirlView requestAdWhirlViewWithDelegate:self];
adWhirlView.delegate = self;
adWhirlView.frame = CGRectMake(0, 430+kAdWhirlViewHeight, kAdWhirlViewWidth, kAdWhirlViewHeight);
[self.parentViewController.view insertSubview:adWhirlView belowSubview:self.view];
[UIView beginAnimations:#"AdWhirlIn" context:nil];
[UIView setAnimationDuration:.5];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
adWhirlView.frame = CGRectMake(0, 430, kAdWhirlViewWidth, kAdWhirlViewHeight);
[UIView commitAnimations];

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