change UIImageView height with UISlider

Question

I have 2 UIImageViews with a picture of a thermometer with no color and one with color. I want to set the height of the colored UIImageView dynamic with a UISlider.

So when the App starts I just want to show the thermometer without any color, when I slide my UISlider I want the colored UIImageView to increase the height. It should increase from 0 to full height(460).

How can I do that?

This is just an example of a more more complex situation.

I've tried with the following, but it just scales the whole picture, I just want to increase the height.

- (IBAction)my_slider:(UISlider *)sender {

    [self.thermo_color setTransform:CGAffineTransformMakeScale(sender.value, sender.value)];

}

Check this link for an example photo: https://i.sstatic.net/PARUT.jpg

Thank You.

Answer 1

Te Controller structure:

-MainView
--UIImageView *themFull (full image with full color)
--UIView *viewAnimated (a white view that you transform for the animation effect)
--UIImageView *themEmpty (empty Image of thermometer)

This Is the good way for do that:

- (IBAction)my_slider:(UISlider *)sender {

    dispatch_async(dispatch_get_main_queue(), ^{

        [self.viewAnimated setFrame:CGRectMake(self.viewAnimated.frame.origin.x,
                                                self.viewAnimated.frame.origin.y,
                                                self.viewAnimated.frame.size.width,
                                                self.viewAnimated.frame.size.width / sender.value)];

    });
}

the size of view have to be the same of the your UIImageViews