Chat bubble button backgroundImage uiimage stretch stretchableImageWithLeftCapWidth: method use, uiimage stretch

Chat bubble button backgroundImage uiimage stretch stretchableImageWithLeftCapWidth: method use, uiimage stretch

-(UIImage *) stretchableImageWithLeftCapWidth :( NSInteger) leftCapWidth topCapHeight :( NSInteger) topCapHeight

This UIImage instance method is used when an image instance is stretched.

1. During Horizontal stretching, the number of leftCapWidth pixels on the Left can be infinitely stretched and other pixels are displayed normally.

2. During vertical stretching, other pixels can be displayed without limit stretched from top to top.