Scaling and stretching of uiimage images developed by iPhone

Sometimes, to reduce the size of the app package, we can use a tiled image to provide only a part of the image and then use code to stretch it.

The system has functions to solve image scaling and stretching problems:

-(Uiimage*) Stretchableimagewithleftcapwidth :(Nsinteger) Leftcapwidth topcapheight :(Nsinteger) Topcapheight;

The leftcapwidth and topcapheight parameters refer to the starting coordinates that do not want to be stretched.

An image of 80*80, if leftcapwidth is 20, topcapheight is 40

The image is scaled at the starting point of (20, 40 ).