You need 2 Global Variables :
- currentScale
- MAX_SCALE(Constant Number)
Example for ZOOM IN :
If Player overlaps Candle ->
Sub-Condition : currentScale < MAX_SCALE :
Add dt to currentScale
Set layer X scale to currentScale
If Player NOT overlaps Candle ->
Sub-Condition : currentScale > 1 :
Subtract dt from currentScale
Set layer X scale to currentScale
There is my screenshot which I made with Construct 2: