SKActionBy Scale: Duration: SpriteKit

Question

I have a problem making one circle big and small using [SKAction scaleBy: duration:]

SKAction *scaleDown = [SKAction scaleBy:0.2 duration:1.8];  
SKAction *scaleUp= [scaleDown reversedAction];
SKAction *fullScale = [SKAction sequence:@[scaleDown, scaleUp, scaleDown, scaleUp]];
[_circleChanging runAction:fullScale];

What I get becomes so small that it disappears and then does not return. It should become small, and then return to its original size, doing this 2 times.

Answer 1

Try:

  SKAction *scaleDown = [SKAction scaleTo:0.2 duration:0.75];
       SKAction *scaleUp= [SKAction scaleTo:1.0 duration:0.75];
       SKAction *fullScale = [SKAction repeatActionForever:[SKAction sequence:@[scaleDown, scaleUp, scaleDown, scaleUp]]];
       [_circleChanging runAction:fullScale];

Answer 2

Not all actions are reversible, but on the contrary sometimes does not mean "return to the original value."

, scaleBy -0.2 . .

:

SKAction *fullScale = [SKAction sequence:
                       @[scaleDown, scaleUp, [scaleDown copy], [scaleUp copy]]];