Question

I’m using Apple’s example «PDFScrollView» to display PDFs on an iPad. This works fine, as long as the PDF-document is in Portrait-Mode.
When the document is in Landscape-mode, though, the document is always shown rotated by 90 degrees.
I found this How to detect the orientation of a PDF document in iPhone SDK – but when I try to get the dimensions of the PDF, the height is always bigger than the width, no matter what orientation the PDF has…

Any ideas?

Answer 1

As mentionend in, the CGPDFPageGetBoxRect(page, kCGPDFMediaBox) always returns the same size for a PDF, no matter what orientation the PDF has.

But the rotation of the page is returned correctly.

So I get the rotation using this code:

rotate =  CGPDFPageGetRotationAngle(page);

And then use the code below which I found here: http://ipdfdev.com/2011/03/23/display-a-pdf-page-on-the-iphone-and-ipad/

switch (rotate) {
        case 0:
            // Translate the origin of the coordinate system at the 
            // bottom left corner of the page rectangle.
            CGContextTranslateCTM(context, 0, cropBox.size.height);
            // Reverse the Y axis to grow from bottom to top.
            CGContextScaleCTM(context, 1, -1);
            break;
        case 90:
            // Reverse the Y axis to grow from bottom to top.
            CGContextScaleCTM(context, 1, -1);
            // Rotate the coordinate system.
            CGContextRotateCTM(context, -M_PI / 2);
            break;
        case 180:
        case -180:
            // Reverse the Y axis to grow from bottom to top.
            CGContextScaleCTM(context, 1, -1);
            // Translate the origin of the coordinate system at the 
            // top right corner of the page rectangle.
            CGContextTranslateCTM(context, cropBox.size.width, 0);
            // Rotate the coordinate system with 180 degrees.
            CGContextRotateCTM(context, M_PI);
            break;
        case 270:
        case -90:
            // Translate the origin of the coordinate system at the 
            // bottom right corner of the page rectangle.
            CGContextTranslateCTM(context, cropBox.size.height, cropBox.size.width);
            // Rotate the coordinate system.
            CGContextRotateCTM(context, M_PI / 2);
            // Reverse the X axis.
            CGContextScaleCTM(context, -1, 1);
            break;
    }

Et voilà – the PDF is displayed in the right orientation