Ios – UIImageView Transform Scale

iosiphoneobjective c

I have a UIButton that when pressed, will make a UIImageView scale slightly larger and then back to its normal size. It's working, but I'm running into a problem where the image eventually keeps getting slightly smaller the more you press the button.

How can I change the code so that the image doesn't get smaller as you press the button? Here's the code I have to scale the image slightly larger and then back to normal:

[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration: 0.2];
myImage.transform = CGAffineTransformScale(myImage.transform, 1.03, 1.03);
[UIView setAnimationDelegate:self];
[UIView commitAnimations];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration: 0.2];             
myImage.transform = CGAffineTransformScale(myImage.transform, 0.97, 0.97);
[UIView setAnimationDelegate:self];
[UIView commitAnimations];

Thanks for any help.

Best Answer

It's math. Scaling something by 1.03 * 0.97 results in scaling factor of 0.9991 and not 1.0. Either use 1.0/1.03 as your second scaling factor or just set myImage.transform to the identity transform (assuming you are not applying other transformations to that view).

Related Solutions

Objective-c – How to scale a UIImageView proportionally

Fixed easily, once I found the documentation!

 imageView.contentMode = .scaleAspectFit

R – change counterclockwise to clockwise with CGAffineTransformIdentity

I'm not sure what the state is when touchesEnded (in terms of rotation) and I'm assuing you chose degreesToRadians(-130) to try and do it partially and expect the next method to do the rest. This should be a better solution that hopefully yields the result you're expecting. I'm not sure what cadran is or why you're rotating that, so I'll just rotate the wheel.

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.2];
    wheel.transform = CGAffineTransformMakeRotation(degreesToRadians(-130));
    // I would recommend that the degrees you rotate be half of whatever your rotation is.
    // this would make the wheel rotate to the home position more evenly
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDidStopSelector:@selector(animatewheelViewToCenter:finished:context:)];
    [UIView commitAnimations];
}

- (void)animatewheelViewToCenter:(NSString *)animationID finished:(NSNumber *)finished context:(id)context {
    [UIView setAnimationBeginsFromCurrentState:YES]; // you might need to make this NO
    [UIView beginAnimations:nil context:NULL];
    [UIViewsetAnimationDuration:0.2];
    wheel.transform = CGAffineTransformIdentity;
    [UIView commitAnimations];
}

EDIT: Actually, I would probably make the rotation (in the example -130 degrees) slightly more than what half would be, because CGAffineTransformIdentity is gonna take the shortest path to go back to regular, so if you go exactly 1/2 way, it may not go the correct direction (clockwise or counter-clockwise) that you want.

Best Answer

Related Solutions

Objective-c – How to scale a UIImageView proportionally

R – change counterclockwise to clockwise with CGAffineTransformIdentity

Related Topic