1. 一句代碼截屏

UIView *view = [self.view snapshotViewAfterScreenUpdates:YES];

2. UIGraphics

- (UIImage *)screenShot {
    
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(SCREEN_WIDTH, SCREEN_HEIGHT), NO, 0.0);
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *screenShotImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return screenShotImage;
}

3. 還有就是之前一個大佬寫的給webview截長圖的

其實就是利用webView的contentSize和webView中的scrollView的contentOffset, 多次截屏, 最后拼接到一張長圖上

- (UIImage *)imageForWebView
{
    // 1.獲取WebView的寬高
    CGSize boundsSize = self.bounds.size;
    CGFloat boundsWidth = boundsSize.width;
    CGFloat boundsHeight = boundsSize.height;
    // 2.獲取contentSize
    CGSize contentSize = self.scrollView.contentSize;
    CGFloat contentHeight = contentSize.height;
    // 3.保存原始偏移量，便于截圖后復位
    CGPoint offset = self.scrollView.contentOffset;
    // 4.設置最初的偏移量為(0,0);
    [self.scrollView setContentOffset:CGPointMake(0, 0)];
    
    NSMutableArray *images = [NSMutableArray array];
    while (contentHeight > 0) {
        // 5.獲取CGContext 5.獲取CGContext
        UIGraphicsBeginImageContextWithOptions(boundsSize, NO, 0.0);
        CGContextRef ctx = UIGraphicsGetCurrentContext();
        // 6.渲染要截取的區域
        [self.layer renderInContext:ctx];
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        // 7.截取的圖片保存起來
        [images addObject:image];
        
        CGFloat offsetY = self.scrollView.contentOffset.y;
        [self.scrollView setContentOffset:CGPointMake(0, offsetY + boundsHeight)];
        contentHeight -= boundsHeight;
    }
    // 8 webView 恢復到之前的顯示區域
    [self.scrollView setContentOffset:offset];
    CGFloat scale = [UIScreen mainScreen].scale;
    CGSize imageSize = CGSizeMake(contentSize.width * scale,
                                  contentSize.height * scale);
    // 9.根據設備的分辨率重新繪制、拼接成完整清晰圖片
    UIGraphicsBeginImageContext(imageSize);
    [images enumerateObjectsUsingBlock:^(UIImage *image, NSUInteger idx, BOOL *stop) {
        [image drawInRect:CGRectMake(0,scale * boundsHeight * idx,scale * boundsWidth,scale * boundsHeight)];
    }];
    UIImage *fullImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return fullImage;
}