iphone certain PDFs rendering as black image
- by skantner
I'm trying to draw the pages of a PDF using the code below. Some PDF's render correctly, but others simply show as a completely black image, or have partial portions rendered and the rest black. In comparing what's going on, the ones that show OK seem to have always have "regular" text in them along with some graphics (diagrams, etc.), while the ones that come out black are typically all graphics (like a page of sheet music, for example). Can anyone point me in the right direction on this?
I building this on the new 3.2 SDK.
Thanks!
// PDF page drawing expects a Lower-Left coordinate system, so we flip the coordinate system
// before we start drawing.
CGContextTranslateCTM(context, 0.0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
// Grab the first PDF page
CGPDFPageRef page = CGPDFDocumentGetPage(myPDF, pageNo);
// We're about to modify the context CTM to draw the PDF page where we want it, so save the graphics state in case we want to do more drawing
CGContextSaveGState(context);
// CGPDFPageGetDrawingTransform provides an easy way to get the transform for a PDF page. It will scale down to fit, including any
// base rotations necessary to display the PDF page correctly.
CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, self.bounds, 0, true);
// And apply the transform.
CGContextConcatCTM(context, pdfTransform);
// Finally, we draw the page and restore the graphics state for further manipulations!
CGContextDrawPDFPage(context, page);
CGContextRestoreGState(context);
