通过路径获取图片及改变图片颜色
NSString *starsPath = [[NSBundle mainBundle] pathForResource:@"star" ofType:@"png"];
UIImage *theImage = [[UIImage alloc] initWithContentsOfFile:starsPath];
theImage= [theImage p_w_picpathWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
stars.tintColor = [UIColor orangeColor];
stars.p_w_picpath = theImage;