如何将NSData转换为PDF？

Question

I have pdf files stored on Parse.com, I want to download them and set them as images. I have googled around trying to find out how to do this but I'm still clueless. I have got my parse object downloading successfully, the pdf file is stored in the field "image"

                //DOWNLOAD IMAGE CODE
                PFFile *image = object[@"image"];
                [image getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {

                    //we have data, now we want to convert it to a UIImage

                }];

just have no idea what to do with the data. Can someone please give me some pointers? thanks

Answer 1

I haven't done this, but I think what you need to do is to first create a data provider out of your data using a call like CGDataProviderCreateWithCFData(), then use the data provider to create a PDF object using CGPDFDocumentCreateWithProvider.

These are Core Foundation calls so you need to do manual memory management of the CF objects (ARC doesn't manage CF objects)

You should be able to Google around using those terms and find code to do what you want.

Answer 2

Are the files store on parse as images or PDF's?

It sounds to me like you've got actual PDF files on parse. You can't just convert them to an image as they aren't images.

If they're PDF files you can save them to disk and then view them with QuickLookPreview https://developer.apple.com/library/prerelease/ios/documentation/NetworkingInternet/Reference/QLPreviewController_Class/index.html#//apple_ref/occ/instp/QLPreviewController/currentPreviewItem

If they're actually images then you simply use: [UIImage imageWithData:data]