从Core Data以pdf格式绘制带有CGRect的UIImage

Question

I'm generating a PDF document on the fly using data that's been outputted from my Core Data graph, however this is proving to be quite difficult.

I'm using the assetlibrary to get the filepath of the image out of the core data graph by using the following:

NSURL *url = [[NSURL alloc] initWithString:bird.photo];
        ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];

        [library assetForURL:url resultBlock:^(ALAsset *asset) {

                     _pdfBirdmage = [UIImage imageWithCGImage:[[asset defaultRepresentation] fullResolutionImage]];


                 } failureBlock:^(NSError *error) {

                     NSLog(@"Couldn't load asset %@ => %@", error, [error localizedDescription]);

                 }];

And this is showing that the image is as the following:

birdphotoview = <UIImage: 0x1caac0>

Obviously, I would like this to be in an image format, such as PNG or JPG in order to write it to the PDF document, using the following code:

[_pdfBirdImage drawInRect:CGRectMake( (pageSize.width - _pdfBirdImage.size.width/2)/2, 350, _pdfBirdImage.size.width/2, _pdfBirdImage.size.height/2)];

However, this is not printing anything to the pdf.

Any help would be brilliant.

Answer 1

Are you using the CGPDF based routines? I think the Y dimension is opposite in that event. I've displayed PDFs before and overlaid data on top (and subsequently then rendered the entire screen back to disk but as an image). If that is the case, I had to transform the existing PDF first. Doesn't sound like your problem, but I don't see any PDF code referenced here, so hard to tell. Regardless, was something along:

UIGraphicsBeginImageContext(pdfPageRectScaled.size);
CGContextRef context = UIGraphicsGetCurrentContext();

// First fill the background with white.
CGContextSetRGBFillColor(context, 1.0f, 1.0f, 1.0f, 1.0f);
CGContextFillRect(context, pdfPageRectScaled);

CGContextSaveGState(context);
// Flip the context so that the PDF page is rendered
// right side up.
CGContextTranslateCTM(context, 0.0f, pdfPageRectScaled.size.height);
CGContextScaleCTM(context, 1.0f, -1.0f);

// Scale the context so that the PDF page is rendered 
// at the correct size for the zoom level.
CGContextScaleCTM(context, pdfScale, pdfScale); 
CGContextDrawPDFPage(context, page);
CGContextRestoreGState(context);