ios 截取指定view的图片

- （void）ScreenImage{

// 1.开启图形上下文

CGSize imageSize = self.view.bounds.size;

UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0.0);

// 2.将某个view的所有内容渲染到图形上下文中

CGContextRef context = UIGraphicsGetCurrentContext();

[self.view.layer renderInContext:context];

// 3.取得图片

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

CGImageRef subimageRef = CGImageCreateWithImageInRect(image.CGImage, CGRectMake(0, 0, 640, 480));

UIImage *subImage = [UIImage imageWithCGImage:subimageRef];

//  文件保存路径

[UIImagePNGRepresentation(subImage) writeToFile:@"/Users/taoyali/Desktop/view.png" atomically:YES];

// 4.关闭上下文

UIGraphicsEndImageContext();

}