How to get location of moving a UIImageView - objective-c

In touchesBegan I have this, and some other irrelevant code. :
CGPoint center;
center = [[self.squareOne.layer presentationLayer] center];
squareOne uses a block-based UIView animation to move. The animation code:
self.squareOne.center = position;
self.squareOne.transform = CGAffineTransformMakeRotation((a + 1) * M_1_PI);
If it really matter this is what position is:
position.x = self.widthOfScreen/8 + self.widthOfScreen;
position.y = y;
//y is any number between 0 and the height of the screen
But when I click the screen, I get the dreaded: Thread 1: signal SIGABRT error. (I say the other code in touchesBegan is irrelevant because those 2 lines of code are the problem. Pretty much the rest are just if-statements which will ultimately just make squareOne become hidden). I am asking how I can get the location of a UIImageView mid-animation when I click the screen. It doesn't matter if you get the center, I just want to know how to get a relative value of squareOne's position while it's moving.

I think the issue is that there is no center on a presentation layer, but you can get a frame. Try this...
CALayer *layer = self.squareOne.layer;
CGRect frame = [[layer presentationLayer] frame];
CGPoint center = CGPointMake(CGRectGetMidX(frame), CGRectGetMaxY(frame));
Hopefully that helps.

Related

How to get object position and size in UIView objective c

I put UIImageView in my Scene from Object library, and give it an image and defined OUTLET in .h file. Now I want to check its coordinates, or center point, or frame X,Y,Width,Height.
I am using
This
CGRect newFrameSize = CGRectMake(recycleBin.frame.origin.x, recycleBin.frame.origin.y,
recycleBin.frame.size.width, recycleBin.frame.size.height);
or
CGRect newFrameSize = recycleBin.frame;
by using this
NSLog(#"%#", NSStringFromCGRect(newFrameSize));
gives same result that is
2013-01-16 21:42:25.101 xyzapp[6474:c07] {{0, 0}, {0, 0}}
I want its actual position and size when viewcontroller loaded, so when user click on image view it will fadeout by zoom-in towards users and will disappear, and when user tap on reset button, it fadein and zoom-in back to original form (reverse to the previous animation).
Also give me hint, how to perform this animation on UIImageView or any button or label. Thx
Unfortunately, you can't check an item's actual frame as set in IB in -viewDidLoad. The earliest you can check it (that I've found) is by overriding -viewDidAppear:. But, since -viewDidAppear: could be called multiple times throughout the life of the view, you need to make sure you're not saving the frame it's in the modified state.
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
if(savedFrame == CGRectZero) {
savedFrame = self.recycleBin.frame;
NSLog(#"Frame: %#", NSStringFromCGRect(savedFrame));
}
}
Where savedFrame is a member variable (or you could make it a property).
From the description of the animation you're wanting, it sounds like adjusting the frame isn't the way to go about it. It sounds like you're wanting to get the effect of the view stretching and fading out (and the reverse when being reset)? If so, some code like this might be more so what you're looking for...
Fade out:
float animationDuration = 2.0f; // Duration of animation in seconds
float zoomScale = 3.0f; // How much to zoom in duration the animation
[UIView animateWithDuration:animationDuration animations:^{
CGAffineTransform transform = CGAffineTransformMakeScale(zoomScale, zoomScale);
self.recycleBin.transform = transform;
self.recycleBin.alpha = 0; // Make fully transparent
}];
And then, to reset the view:
float animationDuration = 2.0f; // Duration of animation in seconds
[UIView animateWithDuration:animationDuration animations:^{
CGAffineTransform transform = CGAffineTransformMakeScale(1.0f, 1.0f);
self.recycleBin.transform = transform;
self.recycleBin.alpha = 1.0; // Make fully opaque
}];
You can play around with the numbers to see if you get the effects you desire. Most animations in iOS are actually extremely simple to do. This code would work for any UIView subclass.
It sounds as if your IBOutlet is not attached to your class.
Open up your view controller header file (if that is where you property declaration is) and look beside the declaration:
Notice how on the first IBOutlet, the circle (to the left of the line number) is filled in. This means that it is connected to your scene. However, the second one is not (the circle is not filled in).

iOS - Math help - base image zooms with pinch gesture need overlaid images adjust X/Y coords relative

I have an iPad application that has a base image UIImageView (in this case a large building or site plan or diagram) and then multiple 'pins' can be added on top of the plan (visually similar to Google Maps). These pins are also UIImageViews and are added to the main view on tap gestures. The base image is also added to the main view on viewDidLoad.
I have the base image working with the pinch gesture for zooming but obviously when you zoom the base image all the pins stay in the same x and y coordinates of the main view and loose there relative positioning on the base image (whose x,y and width,height coordinates have changed).
So far i have this...
- (IBAction)planZoom:(UIPinchGestureRecognizer *) recognizer;
{
recognizer.view.transform = CGAffineTransformScale(recognizer.view.transform, recognizer.scale, recognizer.scale);
recognizer.scale = 1;
for (ZonePin *pin in planContainer.subviews) {
if ([pin isKindOfClass:[ZonePin class]]){
CGRect pinFrame = pin.frame;
// ****************************************
// code to reposition the pins goes here...
// ****************************************
pin.frame = pinFrame;
}
}
}
I need help to calculate the math to reposition the pins x/y coordinates to retain there relative position on the zoomed in or out plan/diagram. The pins obviously do not want to be scaled/zoomed at all in terms of their width or height - they just need new x and y coordinates that are relative to there initial positions on the plan.
I have tried to work out the math myself but have struggled to work it through and unfortunately am not yet acquainted with the SDK enough to know if there is provision available built in to help or not.
Help with this math related problem would be really appreciated! :)
Many thanks,
Michael.
InNeedOfMathTuition.com
First, you might try embedding your UIImageView in a UIScrollView so zooming is largely accomplished for you. You can then set the max and min scale easily, and you can scroll around the zoomed image as desired (especially if your pins are subviews of the UIImageView or something else inside the UIScrollView).
As for scaling the locations of the pins, I think it would work to store the original x and y coordinates of each pin (i.e. when the view first loads, when they are first positioned, at scale 1.0). Then when the view is zoomed, set x = (originalX * zoomScale) and y = (originalY * zoomScale).
I had the same problem in an iOS app a couple of years ago, and if I recall correctly, that's how I accomplished it.
EDIT: Below is more detail about how I accomplished this (I'm looking my old code now).
I had a UIScrollView as a subview of my main view, and my UIImageView as a subview of that. My buttons were added to the scroll view, and I kept their original locations (at zoom 1.0) stored for reference.
In -(void)scrollViewDidScroll:(UIScrollView *)scrollView method:
for (id element in myButtons)
{
UIButton *theButton = (UIButton *)element;
CGPoint originalPoint = //get original location however you want
[theButton setFrame:CGRectMake(
(originalPoint.x - theButton.frame.size.width / 2) * scrollView.zoomScale,
(originalPoint.y - theButton.frame.size.height / 2) * scrollView.zoomScale,
theButton.frame.size.width, theButton.frame.size.height)];
}
For the -(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView method, I returned my UIImageView. My buttons scaled in size, but I didn't include that in the code above. If you're finding that the pins are scaling in size automatically, you might have to store their original sizes as well as original coordinates and use that in the setFrame call.
UPDATE...
Thanks to 'Mr. Jefferson' help in his answer above, albeit with a differing implementation, I was able to work this one through as follows...
I have a scrollView which has a plan/diagram image as a subview. The scrollView is setup for zooming/panning etc, this includes adding UIScrollViewDelegate to the ViewController.
On user double tapping on the plan/diagram a pin image is added as a subview to the scrollView at the touch point. The pin image is a custom 'ZonePin' class which inherits from UIImageView and has a couple of additional properties including 'baseX' and 'baseY'.
The code for adding the pins...
- (IBAction)planDoubleTap:(UITapGestureRecognizer *) recognizer;
{
UIImage *image = [UIImage imageNamed:#"Pin.png"];
ZonePin *newPin = [[ZonePin alloc] initWithImage:image];
CGPoint touchPoint = [recognizer locationInView:planContainer];
CGFloat placementX = touchPoint.x - (image.size.width / 2);
CGFloat placementY = touchPoint.y - image.size.height;
newPin.frame = CGRectMake(placementX, placementY, image.size.width, image.size.height);
newPin.zoneRef = [NSString stringWithFormat:#"%#%d", #"BF", pinSeq++];
newPin.baseX = placementX;
newPin.baseY = placementY;
[planContainer addSubview:newPin];
}
I then have two functions for handling the scrollView interaction and this handles the scaling/repositioning of the pins relative to the plan image. These methods are as follows...
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return planImage;
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
for (ZonePin *pin in planContainer.subviews) {
if ([pin isKindOfClass:[ZonePin class]]){
CGFloat newX, newY;
newX = (pin.baseX * scrollView.zoomScale) + (((pin.frame.size.width * scrollView.zoomScale) - pin.frame.size.width) / 2);
newY = (pin.baseY * scrollView.zoomScale) + ((pin.frame.size.height * scrollView.zoomScale) - pin.frame.size.height);
CGRect pinFrame = pin.frame;
pinFrame.origin.x = newX;
pinFrame.origin.y = newY;
pin.frame = pinFrame;
}
}
}
For reference, the calculations for position the pins, by the nature of them being pins' centres the pin image on the x axis but has the y-axis bottom aligned.
The only thing left for me to do with this is to reverse the calculations used in the scrollViewDidScroll method when I add pins when zoomed in. The code for adding pins above will only work properly when the scrollView.zoomScale is 1.0.
Other than that, it now works great! :)

Why does my view jump when setting the layer anchorPoint in an animation block?

I have a UIPanGestureRecognizer attached to a view in my iOS app. I copied the code from the Touches sample app for the pan handler. When the gesture starts, my code:
Records the original anchor point and center.
Changes the anchor point and center to be around the user's fingers, like so:
CGPoint locationInView = [gestureRecognizer locationInView:target];
CGPoint locationInSuperview = [gestureRecognizer locationInView:target.superview];
target.layer.anchorPoint = CGPointMake(
locationInView.x / target.bounds.size.width,
locationInView.y / target.bounds.size.height
);
target.center = locationInSuperview;
As the gesture progresses, the pan handler continuously changes the center to track the finger movement. So far so good.
When the user lets go, I want the view to animate back to its original starting point. The code that does that looks like this:
[UIView animateWithDuration:2 delay:0 options:UIViewAnimationCurveEaseOut animations:^{
target.center = originalCenter;
target.layer.anchorPoint = originalAnchorPoint;
}];
And that does animate the view back to its original starting point. However, before the animation starts, the view jumps to a different spot in the UI. IOW, let go, it jumps, then it animates back to where it belongs.
I thought perhaps I needed to set the anchor point and center outside the animation, perhaps setting the center to the location in the super view, like when the gesture begins, but that seems to make no difference.
What am I missing here? How can I prevent the jump when the user lets go?
I suspect two issues without trying out what you are doing:
Changing the anchor point changes a view's/layer's position. In order to change an anchor point without modification of the position, you can use some helper like this one:
-(void)setAnchorPoint:(CGPoint)anchorPoint forView:(UIView *)view
{
CGPoint newPoint = CGPointMake(view.bounds.size.width * anchorPoint.x, view.bounds.size.height * anchorPoint.y);
CGPoint oldPoint = CGPointMake(view.bounds.size.width * view.layer.anchorPoint.x, view.bounds.size.height * view.layer.anchorPoint.y);
newPoint = CGPointApplyAffineTransform(newPoint, view.transform);
oldPoint = CGPointApplyAffineTransform(oldPoint, view.transform);
CGPoint position = view.layer.position;
position.x -= oldPoint.x;
position.x += newPoint.x;
position.y -= oldPoint.y;
position.y += newPoint.y;
view.layer.position = position;
view.layer.anchorPoint = anchorPoint;
}
(I'm using that myself in my projects. Found here: Changing my CALayer's anchorPoint moves the view)
Your animation sets the anchor point back to its original value.
You should use the helper above to reset the anchor point. This ensures that the view won't move when changing the anchor. You'll have to do this outside of the animation. Afterwards, use an animation block to change the view's center and animate it to where you want it to be.

How to flip a UIView around the x-axis while simultaneously switching subviews

This question has been asked before but in a slightly different way and I was unable to get any of the answers to work the way I wanted, so I am hoping somebody with great Core Animation skills can help me out.
I have a set of cards on a table. As the user swipes up or down the set of cards move up and down the table. There are 4 cards visible on the screen at any given time, but only the second card is showing its face. As the user swipes the second card flips back onto its face and the next card (depending on the swipe direction) lands in it's place showing its face.
I have set up my card view class like this:
#interface WLCard : UIView {
UIView *_frontView;
UIView *_backView;
BOOL flipped;
}
And I have tried flipping the card using this piece of code:
- (void) flipCard {
[self.flipTimer invalidate];
if (flipped){
return;
}
id animationsBlock = ^{
self.backView.alpha = 1.0f;
self.frontView.alpha = 0.0f;
[self bringSubviewToFront:self.frontView];
flipped = YES;
CALayer *layer = self.layer;
CATransform3D rotationAndPerspectiveTransform = CATransform3DIdentity;
rotationAndPerspectiveTransform.m34 = 1.0 / 500;
rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, M_PI, 1.0f, 0.0f, 0.0f);
layer.transform = rotationAndPerspectiveTransform;
};
[UIView animateWithDuration:0.25
delay:0.0
options: UIViewAnimationCurveEaseInOut
animations:animationsBlock
completion:nil];
}
This code works but it has the following problems with it that I can't seem to figure out:
Only half of the card across the x-axis is animated.
Once flipped, the face of the card is upside down and mirrored.
Once I've flipped the card I cannot get the animation to ever run again. In other words, I can run the animation block as many times as I want, but only the first time will animate. The subsequent times I try to animate lead to just a fade in and out between the subviews.
Also, bear in mind that I need to be able to interact with the face of the card. i.e. it has buttons on it.
If anybody has run into these issues it would be great to see your solutions. Even better would be to add a perspective transform to the animation to give it that extra bit of realism.
This turned out to be way simpler than I thought and I didn't have to use any CoreAnimation libraries to achieve the effect. Thanks to #Aaron Hayman for the clue. I used transitionWithView:duration:options:animations:completion
My implementation inside the container view:
[UIView transitionWithView:self
duration:0.2
options:UIViewAnimationOptionTransitionFlipFromBottom
animations: ^{
[self.backView removeFromSuperview];
[self addSubview:self.frontView];
}
completion:NULL];
The trick was the UIViewAnimationOptionTransitionFlipFromBottom option. Incidentally, Apple has this exact bit of code in their documentation. You can also add other animations to the block like resizing and moving.
Ok, this won't be a complete solution but I'll point out some things that might be helpful. I'm not a Core-Animation guru but I have done a few 3D rotations in my program.
First, there is no 'back' to a view. So if you rotate something by M_PI (180 degrees) you're going to be looking at that view as though from the back (which is why it's upside down/mirrored).
I'm not sure what you mean by:
Only half of the card across the x-axis is animated.
But, it it might help to consider your anchor point (the point at which the rotation occurs). It's usually in the center, but often you need it to be otherwise. Note that anchor points are expressed as a proportion (percentage / 100)...so the values are 0 - 1.0f. You only need to set it once (unless you need it to change). Here's how you access the anchor point:
layer.anchorPoint = CGPointMake(0.5f, 0.5f) //This is center
The reason the animation only ever runs once is because transforms are absolute, not cumulative. Consider that you're always starting with the identity transform and then modifying that, and it'll make sense...but basically, no animation occurs because there's nothing to animate the second time (the view is already in the state you're requesting it to be in).
If you're animating from one view to another (and you can't use [UIView transitionWithView:duration:options:animations:completion:];) you'l have to use a two-stage animation. In the first stage of the animation, for the 'card' that is being flipped to backside, you'll rotate the view-to-disappear 'up/down/whatever' to M_PI_2 (at which point it will be 'gone', or not visible, because of it's rotation). And in the second stage, you're rotate the backside-of-view-to-disappear to 0 (which should be the identity transform...aka, the view's normal state). In addition, you'll have to do the exact opposite for the 'card' that is appearing (to frontside). You can do this by implementing another [UIView animateWithDuration:...] in the completion block of the first one. I'll warn you though, doing this can get a little bit complicated. Especially since you're wanting views to have a 'backside', which will basically require animating 4 views (the view-to-disappear, the view-to-appear, backside-of-view-to-disappear, and the backside-of-view-to-appear). Finally, in the completion block of the second animation you can do some cleanup (reset view that are rotated and make their alpha 0.0f, etc...).
I know this is complicated, so you might want read some tutorial on Core-Animation.
#Aaron has some good info that you should read.
The simplest solution is to use a CATransformLayer that will allow you to place other CALayer's inside and maintain their 3D hierarchy.
For example to create a "Card" that has a front and back you could do something like this:
CATransformLayer *cardContainer = [CATransformLayer layer];
cardContainer.frame = // some frame;
CALayer *cardFront = [CALayer layer];
cardFront.frame = cardContainer.bounds;
cardFront.zPosition = 2; // Higher than the zPosition of the back of the card
cardFront.contents = (id)[UIImage imageNamed:#"cardFront"].CGImage;
[cardContainer addSublayer:cardFront];
CALayer *cardBack = [CALayer layer];
cardBack.frame = cardContainer.bounds;
cardBack.zPosition = 1;
cardBack.contents = (id)[UIImage imageNamed:#"cardBack"].CGImage; // You may need to mirror this image
[cardContainer addSublayer:cardBack];
With this you can now apply your transform to cardContainer and have a flipping card.
#Paul.s
I followed your approach with card container but when i applt the rotation animation on card container only one half of the first card rotates around itself and finally the whole view appears.Each time one side is missing in the animation
Based on Paul.s this is updated for Swift 3 and will flip a card diagonally:
func createLayers(){
transformationLayer = CATransformLayer(layer: CALayer())
transformationLayer.frame = CGRect(x: 15, y: 100, width: view.frame.width - 30, height: view.frame.width - 30)
let black = CALayer()
black.zPosition = 2
black.frame = transformationLayer.bounds
black.backgroundColor = UIColor.black.cgColor
transformationLayer.addSublayer(black)
let blue = CALayer()
blue.frame = transformationLayer.bounds
blue.zPosition = 1
blue.backgroundColor = UIColor.blue.cgColor
transformationLayer.addSublayer(blue)
let tgr = UITapGestureRecognizer(target: self, action: #selector(recTap))
view.addGestureRecognizer(tgr)
view.layer.addSublayer(transformationLayer)
}
Animate a full 360 but since the layers have different zPositions the different 'sides' of the layers will show
func recTap(){
let animation = CABasicAnimation(keyPath: "transform")
animation.delegate = self
animation.duration = 2.0
animation.fillMode = kCAFillModeForwards
animation.isRemovedOnCompletion = false
animation.toValue = NSValue(caTransform3D: CATransform3DMakeRotation(CGFloat(Float.pi), 1, -1, 0))
transformationLayer.add(animation, forKey: "arbitrarykey")
}

Synchronised scrolling between two instances of NSScrollView

I have two instances of NSScrollView both presenting a view on the same content. The second scroll view however has a scaled down version of the document view presented in the first scroll view. Both width and height can be individually scaled and the original width - height constraints can be lost, but this is of no importance.
I have the synchronised scrolling working, even taking into account that the second scroll view needs to align its scrolling behaviour based on the scaling. There's one little snag I've been pulling my hairs out over:
As both views happily scroll along the smaller view needs to slowly catch up with the larger view, so that they both "arrive" at the end of their document at the same time. Right now this is not happening and the result is that the smaller view is at "end-of-document" before the larger view.
The code for synchronised scrolling is based on the example found in Apple's documentation titled "Synchronizing Scroll Views". I have adapted the synchronizedViewContentBoundsDidChange: to the following code:
- (void) synchronizedViewContentBoundsDidChange: (NSNotification *) notification {
// get the changed content view from the notification
NSClipView *changedContentView = [notification object];
// get the origin of the NSClipView of the scroll view that
// we're watching
NSPoint changedBoundsOrigin = [changedContentView documentVisibleRect].origin;;
// get our current origin
NSPoint curOffset = [[self contentView] bounds].origin;
NSPoint newOffset = curOffset;
// scrolling is synchronized in the horizontal plane
// so only modify the x component of the offset
// "scale" variable will correct for difference in size between views
NSSize ownSize = [[self documentView] frame].size;
NSSize otherSize = [[[self synchronizedScrollView] documentView] frame].size;
float scale = otherSize.width / ownSize.width;
newOffset.x = floor(changedBoundsOrigin.x / scale);
// if our synced position is different from our current
// position, reposition our content view
if (!NSEqualPoints(curOffset, changedBoundsOrigin)) {
// note that a scroll view watching this one will
// get notified here
[[self contentView] scrollToPoint:newOffset];
// we have to tell the NSScrollView to update its
// scrollers
[self reflectScrolledClipView:[self contentView]];
}
}
How would I need to change that code so that the required effect (both scroll bars arriving at an end of document) is achieved?
EDIT: Some clarification as it was confusing when I read it back myself: The smaller view needs to slow down when scrolling the first view reaches the end. This would probably mean re-evaluating that scaling factor... but how?
EDIT 2: I changed the method based on Alex's suggestion:
NSScroller *myScroll = [self horizontalScroller];
NSScroller *otherScroll = [[self synchronizedScrollView] horizontalScroller];
//[otherScroll setFloatValue: [myScroll floatValue]];
NSLog(#"My scroller value: %f", [myScroll floatValue]);
NSLog(#"Other scroller value: %f", [otherScroll floatValue]);
// Get the changed content view from the notification.
NSClipView *changedContentView = [notification object];
// Get the origin of the NSClipView of the scroll view that we're watching.
NSPoint changedBoundsOrigin = [changedContentView documentVisibleRect].origin;;
// Get our current origin.
NSPoint curOffset = [[self contentView] bounds].origin;
NSPoint newOffset = curOffset;
// Scrolling is synchronized in the horizontal plane so only modify the x component of the offset.
NSSize ownSize = [[self documentView] frame].size;
newOffset.x = floor(ownSize.width * [otherScroll floatValue]);
// If our synced position is different from our current position, reposition our content view.
if (!NSEqualPoints(curOffset, changedBoundsOrigin)) {
// Note that a scroll view watching this one will get notified here.
[[self contentView] scrollToPoint: newOffset];
// We have to tell the NSScrollView to update its scrollers.
[self reflectScrolledClipView:[self contentView]];
}
Using this method the smaller view is "overtaken" by the larger view when both scrollers reach a value of 0.7, which is not good. The larger view then scrolls past its end of document.
I think you might be approaching this in the wrong way. I think you should be getting a percentage of how far down each scroll be is scrolled in relation to itself and apply that to the other view. One example of how this could be done is this way using NSScroller's -floatValue:
NSScroller *myScroll = [self verticalScroller];
NSScroller *otherScroll = [otherScrollView verticalScroller];
[myScroll setFloatValue:otherScroll.floatValue];
I finally figured it out. The answer from Alex was a good hint but not the full solution as just setting the float value of a scroller doesn't do anything. That value needs translation to specific coordinates to which the scroll view needs to scroll its contents.
However, due to differences in size of the scrolled document view, you cannot just simply use this value, as the scaled down view will be overtaken by the "normal" view at some point. This will cause the normal view to scroll past its end of document.
The second part of the solution was to make the normal sized view wait with scrolling until the scaled down view has scrolled its own width.
The code:
// Scrolling is synchronized in the horizontal plane so only modify the x component of the offset.
NSSize ownSize = [[self documentView] frame].size;
newOffset.x = MAX(floor(ownSize.width * [otherScroll floatValue] - [self frame].size.width),0);
The waiting is achieved by subtracting the width of the scroll view from the width times the value of the scroller. When the scaled down version is still traversing its first scroll view width of pixels, this calculation will result in a negative offset. Using MAX will prevent strange effects and the original view will quietly wait until the value turns positive and then start its own scrolling. This solution also works when the user resizes the app window.