Translate

Use the translate() method to calculate the value needed to move a point from /start/ to /end/ under a given scale factor.

Use

x = translate(0.6, 100, 350) will return a the required value to translate x from 100 to 350 under a 60% scale factor. the fact that it is x does not matter. only the start and end points matter because the scale() function is symetrical.