iOS 通过一个View生成一个图片

#pragma mark - 全屏截图

+ (UIImage *)shotScreen

{

    UIWindow *window = [UIApplication sharedApplication].keyWindow;

    UIGraphicsBeginImageContext(window.bounds.size);

    [window.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

 

#pragma mark - 截取view生成一张图片

+ (UIImage *)shotWithView:(UIView *)view

{

    UIGraphicsBeginImageContext(view.bounds.size);

    [view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

 

#pragma mark - 截取view中某个区域生成一张图片

+ (UIImage *)shotWithView:(UIView *)view scope:(CGRect)scope

{

    CGImageRef imageRef = CGImageCreateWithImageInRect([self shotWithView:view].CGImage, scope);

    UIGraphicsBeginImageContext(scope.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGRect rect = CGRectMake(0, 0, scope.size.width, scope.size.height);

    CGContextTranslateCTM(context, 0, rect.size.height);//下移

    CGContextScaleCTM(context, 1.0f, -1.0f);//上翻

    CGContextDrawImage(context, rect, imageRef);

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    CGImageRelease(imageRef);

    CGContextRelease(context);

    return image;

}

 

#pragma mark - 方法一：View的大小不大于手机屏幕

+ (UIImage *)snapshotWithView:(UIView *)view

{

    CGSize size = view.bounds.size;

    UIGraphicsBeginImageContextWithOptions(size, YES, 0);

    [view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES];

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;

}

 

#pragma mark - 方法二：View的大小大于手机屏幕

+ (UIImage *) snapshotWithScrollView:(UIScrollView *)scrollView

{

    UIImage* image = nil;

    UIGraphicsBeginImageContext(scrollView.contentSize);

    {

        CGPoint savedContentOffset = scrollView.contentOffset;

        CGRect savedFrame = scrollView.frame;

        scrollView.contentOffset = CGPointZero;

        scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);

        

        [scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];

        image = UIGraphicsGetImageFromCurrentImageContext();

        

        scrollView.contentOffset = savedContentOffset;

        scrollView.frame = savedFrame;

    }

    UIGraphicsEndImageContext();

    

    if (image != nil) {

        return image;

    }

    return nil;

}