如何将CGPDFDocument/CGPDFPage附加到MFMailComposeViewController [英] How to attach CGPDFDocument/CGPDFPage to MFMailComposeViewController

问题描述

我在本地存储器上存储了多页pdf文档.我想从该pdf文档中提取任何页面，并将其转换为NSData以将其附加到"MFMailComposeViewController".使用以下代码行，我可以轻松检索所需的页面...

I have a muti page pdf document stored on local storage. I want to extract any page out of that pdf doc and convert it into NSData to attach it with 'MFMailComposeViewController'. With the following lines of code, I can easily retrive the required page...

CGPDFDocumentRef pdfDoc=CGPDFDocumentCreateWithURL(pdfURL);
CGPDFPageRef pdfPage = CGPDFDocumentGetPage(pdfDoc, pageNumber);

但是我找不到将pdfPage转换为NSData的方法，以便可以将其与邮件一起附加.

But I am unable to find a way to convert pdfPage into NSData so that I can attach it with mail.

注意:的要求是以PDF格式附加页面，因此请不要建议将PDF转换为PNG或JPEG.

NOTE: The requirement is to attach page in PDF format, so please DON'T suggest converting PDF into PNG or JPEG.

推荐答案

CGPDF主要用于从PDF绘图到PDF，而不用于转换PDF数据.因此，如果要提取页面，则必须绘制.举例来说:

CGPDF is primarily for drawing from and to PDF, not for converting PDF data. Therefore, if you want to extract a page, you'll have to draw it. Use for example:

// input
CGDataProviderRef provider = CGDataProviderCreateWithCFData((__bridge CFDataRef)inputData);
CGPDFDocumentRef document = CGPDFDocumentCreateWithProvider(provider);
CGPDFPageRef page = CGPDFDocumentGetPage(document, pageIndex);
CGRect mediaBox = CGPDFPageGetBoxRect(page, kCGPDFMediaBox);
// output
CGDataConsumerRef consumer = CGDataConsumerCreateWithCFData((__bridge CFMutableDataRef)outputData);
CGContextRef context = CGPDFContextCreate(consumer, &mediaBox, NULL);
// draw
CGContextBeginPage(context, &mediaBox);
CGContextDrawPDFPage(context, page);
CGContextEndPage(context);
// cleanup
CGDataProviderRelease(provider);
CGPDFDocumentRelease(document);
CGDataConsumerRelease(consumer);
CGContextRelease(context);

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