从UIWebView或UIView获取PDF/PNG作为输出

可以使用UIView上的以下类别创建PDF文件:

#import <QuartzCore/QuartzCore.h>

@implementation UIView(PDFWritingAdditions)

- (void)renderInPDFFile:(NSString*)path
{
    CGRect mediaBox = self.bounds;
    CGContextRef ctx = CGPDFContextCreateWithURL((CFURLRef)[NSURL fileURLWithPath:path], &mediaBox, NULL);

    CGPDFContextBeginPage(ctx, NULL);
    CGContextScaleCTM(ctx, 1, -1);
    CGContextTranslateCTM(ctx, 0, -mediaBox.size.height);
    [self.layer renderInContext:ctx];
    CGPDFContextEndPage(ctx);
    CFRelease(ctx);
}

@end

坏消息:UIWebView不会在PDF中创建好的形状和文本,而是将自己作为图像呈现到PDF中。

从web视图创建图像很简单:

UIImage* image = nil;

UIGraphicsBeginImageContext(offscreenWebView_.frame.size);
{
    [offscreenWebView_.layer renderInContext: UIGraphicsGetCurrentContext()];
    image = UIGraphicsGetImageFromCurrentImageContext();
}
UIGraphicsEndImageContext();

一旦你有了图像,你可以保存为PNG格式。

创建PDF也可以用非常类似的方式实现,但只能在尚未发布的iPhone OS版本上实现。

@mjdth,试试看 fileURLWithPath:isDirectory: 相反 URLWithString 也不适合我。

@implementation UIView(PDFWritingAdditions)

- (void)renderInPDFFile:(NSString*)path
{
    CGRect mediaBox = self.bounds;
    CGContextRef ctx = CGPDFContextCreateWithURL((CFURLRef)[NSURL fileURLWithPath:path isDirectory:NO], &mediaBox, NULL);

    CGPDFContextBeginPage(ctx, NULL);
    CGContextScaleCTM(ctx, 1, -1);
    CGContextTranslateCTM(ctx, 0, -mediaBox.size.height);
    [self.layer renderInContext:ctx];
    CGPDFContextEndPage(ctx);
    CFRelease(ctx);
}

@end

下面的代码将UIWebView的(完整)内容转换为UIImage。

渲染完UIImage后,我将其作为PNG写入磁盘以查看结果。

UIImage *image = nil;
CGRect oldFrame = webView.frame;

// Resize the UIWebView, contentSize could be > visible size
[webView sizeToFit];
CGSize fullSize = webView.scrollView.contentSize;

// Render the layer content onto the image  
UIGraphicsBeginImageContext(fullSize);
CGContextRef resizedContext = UIGraphicsGetCurrentContext();
[webView.layer renderInContext:resizedContext];
image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

// Revert the UIWebView back to its old size
webView.frame = oldFrame;

// Write the UIImage to disk as PNG so that we can see the result
NSString *path= [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Test.png"];
[UIImagePNGRepresentation(image) writeToFile:path atomically:YES];

注意:确保UIWebView已完全加载(UIWebViewDelegate或loading属性)。