截图截长图高清图

May 4, 2016

最近发现百度地图有对公交路线(scrollView)截图的功能。在这里尝试实现对scrollView截图。

对UIScrollView截图的方法:

- (IBAction) renderScrollViewToImage:(UIScrollView *)scrollView
{
    UIImage* image = nil;

    //UIGraphicsBeginImageContext(scrollView.contentSize);
    //retina屏截屏
    UIGraphicsBeginImageContextWithOptions(scrollView.contentSize, 0, 0);
    {
        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) {
        [UIImagePNGRepresentation(image) writeToFile: @"/Users/tyrad/Desktop/image3.png" atomically: YES];
    }
}

对scrollView截取pdf（最后调用writeToFile:方法）

- (NSMutableData*)createPDFfromUIScrollView:(UIScrollView*)scrollView{
    
    NSMutableData *pdfData = [NSMutableData data];
    
    NSLog(@"%@",NSStringFromCGSize([scrollView contentSize]));
    
    UIGraphicsBeginPDFContextToData(pdfData, (CGRect){0,0, scrollView.contentSize}, nil);
    UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, scrollView.contentSize.width,scrollView.contentSize.height), nil);    
    CGContextRef pdfContext = UIGraphicsGetCurrentContext();
    
    CGRect origSize = scrollView.frame; 
    CGRect newSize = origSize;    
    newSize.size = scrollView.contentSize;
    
    [scrollView setFrame:newSize];    
    [scrollView.layer renderInContext:pdfContext];    
    [scrollView setFrame:origSize];
    
    UIGraphicsEndPDFContext();
    return pdfData;
}

参考 stackoverflow getting-a-screenshot-of-a-uiscrollview iOS中将UIScrollView转换保存成PDF文件数据 iOS中正确的截屏姿势