becuase I app will take lot of memory to load font bytes to use my font. so when I open another app the system will release my app right? how to prevent the system release my app?

I am not using textView but using UIGraphics to drawString and save it as png UIGraphicsBeginImageContext(CGSize(300,60)); var gra=UIGraphicsGetCurrentContext(); and then use NSAttribtedString to drawString