iOS截图功能

-(UIImage *)captureScreenWithRect:(CGRect)rect{

    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, YES, 1);

    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();

    UIImage *resultImg = [UIImage imageWithCGImage:CGImageCreateWithImageInRect(img.CGImage, rect)];

    UIGraphicsEndImageContext();

    return resultImg;

}