So I'm trying to perform a (seemingly) simple transform animation on a UIImageView by just moving it up 100 points. This is my code:
[UIView animateWithDuration:1 delay:1 options:nil animations:^(void) {
CGAffineTransform tf = CGAffineTransformMakeTranslation(0, -100);
[image setTransform:tf];
} completion:^(BOOL finished) {} ];
It works...but it for some reason chooses a new origin for my UIImageView to start from. For example, if the image's original center coordinates are (300, 400), then by my code it should translate up 100 points to (300, 300). But for some reason, the code makes the image start a little bit lower than where it should, like around (300, 450), and then it'll move up 100 to (300, 350). How can I get it to do the animation from where the image is originally?
If you prefer to use transformation for this procedure, then you should try to get original transform and translate it by 100 px.
[image setTransform:CGAffineTransformTranslate(image.transform, 0, -100)];
If your goal is to translate the subview relative to its superview's coordinate system, you'll have more predictable results simply animating the center property:
[UIView animateWithDuration: 1.0 animations:^{
image.center = CGPointMake(image.center.x, image.center.y - 100);
}];
The transform property expresses an affine transform relative to the center property (or the layer's anchorPoint, if changed).
i'm having the same problem. if i want to translate my label 100 on the y-axis, it will start the animation -50 in the y, then moves it 100 from there. if i move it 200 in the y, it starts the animation -100 in the y, then moves it 200 from there. it's very frustrating.
#stackoverflowmaster, were you ever able to figure this out?
UPDATE: you must uncheck the "Use Auto Layout" option in the file inspector for whatever object you're trying to use. this took me way too long to figure out, hope it saves someone else some time.
Related
Hi guys I am trying to rotate view on y,z axis I am successful with the following code but I want to rotate this on its end, now it is rotating from centre, I searched and I got anchorPoint property of layer to make it rotate but it makes unwanted translation of my view also it is not working
leftDoorView.layer.anchorPoint = CGPointMake(0.5,0);
// Code to rotate view on Y axis and slight translate on Z-axis
angle -= 1.57f;
[UIView animateWithDuration:0.5 animations:^{
CATransform3D transloate = CATransform3DMakeTranslation(0, 0, -(leftDoorView.frame.size.width/2.0));
CATransform3D rotate = CATransform3DMakeRotation(angle, 0, 1, 0);
CATransform3D mat = CATransform3DConcat(rotate, transloate);
leftDoorView.layer.transform = CATransform3DPerspect(mat, CGPointMake(0, 0), 500);
}];
For more Info I want to make Menu effect like Taasky app any help will be really appreciated
Perhaps the Ray Wenderlich tutorial about Taasky menu can help. Especially the "Adding Perspective to Your Menu" section.
For further information about animations, there is also documentation provided by Apple and nice anchor point explanation by David Ronnqvist.
I have the following super simple animation, I'm basically rotating a view 2 radians from its original angle/center, it rotates fine my only misunderstanding is why does the view move from its original position when the rotation occurs.
[UIView animateWithDuration:1.0 animations:^{
self.someView.transform = CGAffineTransformMakeRotation( 2 );
}];
Why does the view moves when rotated with the code above?
I'm currently trying to discern the information in the CGAffineTransform Reference.
Understanding the anchor point.
I found this threads but it doesn't show a concrete answer.
Why rotating imageView, it changes position?
Thanks a lot
You need to set the anchor point of your view to rotate around.
self.somview.layer.anchorPoint = CGPointMake(0.5, 0.5);
Then start the rotation.
From Apple documentations
#property(nonatomic) CGAffineTransform transform Changes to this
property can be animated. Use the beginAnimations:context: class
method to begin and the commitAnimations class method to end an
animation block. The default is whatever the center value is (or
anchor point if changed)
Link: https://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CALayer_class/Introduction/Introduction.html#//apple_ref/occ/instp/CALayer/anchorPoint
image from here http://www.raywenderlich.com/9864/how-to-create-a-rotating-wheel-control-with-uikit
- As you see the anchor point is the point with the value from 0.0 - 1.0 for X and Y
when you rotate the rotation will be around these points
NOTE: you need to import QuartzCore
I am adding another answer due to #fs_tigre request. The problem is with the auto layouts in your xib file, unfortunately is it unknown why that affects the transform.
Now here is the steps I did to solve the issue:
1- first you need to get rid off your auto layout (yes, you have to)
uncheck Use Autolayout
2- remove all constraints and autoresizing masks for your view that will be rotated, as in the screenshot
(Here I have my blue box, see on the right autoresizing, nothing is selected)
I have made some changes for your rotation's code
self.someView.layer.anchorPoint = CGPointMake(0.5, 0.5);
// one degree = pi/180. so...
// rotate by 90
CGFloat radians = (M_PI/180) * 90;
[UIView animateWithDuration:1.0 animations:^{
self.someView.transform = CGAffineTransformRotate(self.someView.transform, radians);
}];
Click rotate and see the magic :)
The "anchor" of CGAffineTransformMakeRotation is the X,Y of the view. You can try this:
CGPoint center = self.someView.center;
[UIView animateWithDuration:1.0 animations:^{
self.someView.transform = CGAffineTransformMakeRotation( 2 );
self.someView.center = center;
}];
I expanded and moved a label (instructionLabel), then returned it to its original size but left it in the new position.
[UIView animateWithDuration:0.5
animations:^{
CGAffineTransform scale = CGAffineTransformMakeScale(2.0, 2.0);
CGAffineTransform translate = CGAffineTransformMakeTranslation(0.0, -70.0); // up 70
self.instructionsLabel.transform = CGAffineTransformConcat(scale,translate);
}
completion:^(BOOL finished) {
[UIView animateWithDuration:0.25
animations:^{
CGAffineTransform scale = CGAffineTransformMakeScale(1.0,1.0);
CGAffineTransform translate = CGAffineTransformMakeTranslation(0,-70.0); //left in place up 70
self.instructionsLabel.transform = CGAffineTransformConcat(scale, translate);
}
completion:^(BOOL finished) {}
];
Later, I explicitly use CGPointMake to put the label back in its original spot, but it remains in the translated position (70 pts up from its original place).
instructionsLabel.frame = CGRectMake(384, 601, 655, 40);
//Adding this doesn't make any difference, in or out.
instructionsLabel.center=CGPointMake(384, 601);
I have verified by Breaks and NSLog that the CGPointMake and CGRectMake statements are reached...they just don't work after that affine transformation. Does anyone know why?
(I don't want to move the label back immediately after the translation routine, but I might have to if I can't figure out why the CGPointMake routine doesn't do it.)
Thanks for any suggestions.
-Rob
Unless Im mistaken one of the major reason for using affine transform to scale, move etc views is that, that you can later set transform to CGAffineTransformIdentity this will cancel out any transforms you have applied. I believe that your problem here is that you are setting center to what ever position it of before you applied translate transform. View indeed moves to that point + whatever transform is applied to that view. So just set transform identity.
I want to simultaneously scale and translate a CALayer from one CGrect (a small one, from a button) to a another (a bigger, centered one, for a view). Basically, the idea is that the user touches a button and from the button, a CALayer reveals and translates and scales up to end up centered on the screen. Then the CALayer (through another button) shrinks back to the position and size of the button.
I'm animating this through CATransform3D matrices. But the CALayer is actually the backing layer for a UIView (because I also need Responder functionality). And while applying my scale or translation transforms separately works fine. The concatenation of both (translation, followed by scaling) offsets the layer's position so that it doesn't align with the button when it shrinks.
My guess is that this is because the CALayer anchor point is in its center by default. The transform applies translation first, moving the 'big' CALayer to align with the button at the upper left corner of their frames. Then, when scaling takes place, since the CALayer anchor point is in the center, all directions scale down towards it. At this point, my layer is the button's size (what I want), but the position is offset (cause all points shrank towards the layer center).
Makes sense?
So I'm trying to figure out whether instead of concatenating translation + scale, I need to:
translate
change anchor point to upper-left.
scale.
Or, if I should be able to come up with some factor or constant to incorporate to the values of the translation matrix, so that it translates to a position offset by what the subsequent scaling will in turn offset, and then the final position would be right.
Any thoughts?
You should post your code. It is generally much easier for us to help you when we can look at your code.
Anyway, this works for me:
- (IBAction)showZoomView:(id)sender {
[UIView animateWithDuration:.5 animations:^{
self.zoomView.layer.transform = CATransform3DIdentity;
}];
}
- (IBAction)hideZoomView:(id)sender {
CGPoint buttonCenter = self.hideButton.center;
CGPoint zoomViewCenter = self.zoomView.center;
CATransform3D transform = CATransform3DIdentity;
transform = CATransform3DTranslate(transform, buttonCenter.x - zoomViewCenter.x, buttonCenter.y - zoomViewCenter.y, 0);
transform = CATransform3DScale(transform, .001, .001, 1);
[UIView animateWithDuration:.5 animations:^{
self.zoomView.layer.transform = transform;
}];
}
In my test case, self.hideButton and self.zoomView have the same superview.
I'm working on a drawing app.
I want the user to be able to "drop" a shape on the screen and then move, resize or rotate it as desired.
The problem is with the rotation. I have the moving and resizing working fine.
I did this before with a rather complex and memory/processor-intensive process, which I am now trying to improve.
I've searched and searched but haven't found an answer similar to what I'm trying to do.
Basically, let's say the user drops a square on the "surface". Then, they tap it and get some handles. They can touch anywhere and pan to move the square around (working already), touch and drag on a resize handle to resize the square (working already), or grab the rotation handle to have the square rotate around its center.
I've looked into drawing the square using UIBezierPath or just having it be a subclass of UIView that I fill.
In either case, I'm trying to rotate the UIView itself, not some contents inside. Every time I try to rotate the view, either nothing happens, the view vacates the screen or it rotates just a little bit and stops.
Here's some of the code I've tried (this doesn't work, and I've tried a lot of different approaches to this):
- (void) rotateByAngle:(CGFloat)angle
{
CGPoint cntr = [self center];
CGAffineTransform move = CGAffineTransformMakeTranslation(-1 * cntr.x, -1 * cntr.y);
[[self path] applyTransform:move];
CGAffineTransform rotate = CGAffineTransformMakeRotation(angle * M_PI / 180.0);
[[self path] applyTransform:rotate];
[self setNeedsDisplay];
CGAffineTransform moveback = CGAffineTransformMakeTranslation(cntr.x, cntr.y);
[[self path] applyTransform:moveback];
}
In case it isn't obvious, the thinking here it to move the view to the origin (0,0), rotate around that point and then move it back.
In case you're wondering, "angle" is calculated correctly. I've also wrapped the code above in a [UIView beginAnimations:nil context:NULL]/[UIView commitAnimations] block.
Is it possible to rotate a UIView a "custom" amount? I've seen/done it before where I animate a control to spin, but in those examples, the control always ended up "square" (i.e., it rotated 1 or more full circles and came back to its starting orientation).
Is it possible to perform this rotation "real-time" in response to UITouches? Do I need to draw the square as an item in the layer of the UIView and rotate the layer instead?
Just so you know, what I had working before was a shape drawn by a set of lines or UIBezierPaths. I would apply a CGAffineTransform to the data and then call the drawRect: method, which would re-draw the object inside of a custom UIView. This UIView would host quite a number of these items, all of which would need to be re-drawn anytime one of them needed it.
So, I'm trying to make the app more performant by creating a bunch of UIView subclasses, which will only get a command to re-draw when the user does something with them. Apple's Keynote for the iPad seems to accomplish this using UIGestureRecognizers, since you have to use two fingers to rotate an added shape. Is this the way to go?
Thoughts?
Thanks!
-(void)rotate{
CGAffineTransform transform;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:1.0];
[UIView setAnimationCurve:UIViewAnimationOptionBeginFromCurrentState];
myView.alpha = 1;
transform = CGAffineTransformRotate(myView.transform,0.5*M_PI);
[myView setUserInteractionEnabled:YES];
myView.transform = transform;
[UIView commitAnimations];
}
This might help.
for just simple rotation you might leave out the Animation:
-(void)rotate:(CGFloat)angle
{
CGAffineTransform transform = CGAffineTransformRotate( myView.transform, angle * M_PI / 180.0 );
myView.transform = transform;
}
I use a simple NSTimer to control a animation.