iOS - Animate movement of an image without effects

Question

I would like to animate the movement of an image without effects. To animate it normally, I could use:

[UIView animateWithDuration:2.5f animations:^{
    CGRect currentFrame=self.image.frame;
    currentFrame.origin.x-=10;

    [self.image setFrame:currentFrame];

}];

Yet, I found that if this method is used, the image gradually speeds up, goes a little faster, then gradually comes to a stop.

Is there any way to animate the movement of a UIImageView, keeping the view at the same speed the entire time?

Answer 1

Your animation speeds up and slows down because it uses the "natural" UIViewAnimationOptionCurveEaseInOut curve. Use UIViewAnimationOptionCurveLinear option to use constant speed motion:

[UIView animateWithDuration:2.5f
    delay:0
    options:UIViewAnimationOptionCurveLinear
    animations:^{
        CGRect currentFrame=self.image.frame;
        currentFrame.origin.x-=10;
        [self.image setFrame:currentFrame];
    } 
    completion:^(BOOL finished){
    }
];

Answer 2

[UIView animateWithDuration:1.0 delay:0.0 options:0 animations:^{

} completion:^(BOOL finished) {

}];