Learning Gravity, Basic Physics, and Camera Controls: An Angry Birds-like Game, Part I - Learn GameSalad for iOS: Game Development for iPhone, iPad, and HTML5 - page 186

Figure 6-31. Interpolate the width of the camera size
You can play with the value of the width as well as the duration. I used 920
because I like the effect of doubling the value over 2 seconds. I recommend that
you play around to find values you prefer.
Drag and drop an Interpolate behavior into the Throwing rule and change the
settings to:
 Interpolate Attribute: Current Scene.Camera.Size.Height
 To: 640
 Duration: 2
 Function: Linear
Hit the Preview button to try this new effect.
Zooming In
Intuitively, you can say that if you reduce the camera size, you will create a
zoom-in effect. And you are absolutely right!
In order to trigger the effect after the zoom out, add a timer of 2 seconds. In the
next chapter, you will change the time to add a rule that will trigger the zoom-in
when there is a contact with a target.
Drag and drop a Timer behavior into the Throwing rule of the Projectile actor
instance and change the settings to ''After'' ''2'' seconds.
Duplicate these two Interpolate behaviors (drag+Option key) into the timer.
Change the settings of the Interpolate behaviors you just duplicated to Width:
460 and Height: 320, as shown in Figure 6-32.