Question

How can I access hyperlinks in PDF documents on the iPhone and iPad?

I want to set links on the content of an e-book.

Answer 1

Use following function to put UIButtons on the links in PDF. This will draw Buttons on your UIView. You have to pass your page as parameter. Currently it will draw button with type UIButtonTypeRoundedRect you change afterwards it to custom so it will be hidden. Initially buttons may be drawn other place than link so you need to adjust x/y position according to you requirement.

-(void)drawLinks:(CGPDFPageRef)thisPage
{
    CGPDFDictionaryRef pageDictionary = CGPDFPageGetDictionary(thisPage);

    CGPDFArrayRef outputArray;
    if(!CGPDFDictionaryGetArray(pageDictionary,"Annots", &outputArray)) 
    {
        return;
    }

    int arrayCount = CGPDFArrayGetCount( outputArray );
    if(!arrayCount) 
    {
        //continue;
    }

    for( int j = 0; j < arrayCount; ++j ) 
    {
        CGPDFObjectRef aDictObj;
        if(!CGPDFArrayGetObject(outputArray, j, &aDictObj)) 
        {
            return;
        }

        CGPDFDictionaryRef annotDict;
        if(!CGPDFObjectGetValue(aDictObj, kCGPDFObjectTypeDictionary, &annotDict)) {
            return;
        }

        CGPDFDictionaryRef aDict;
        if(!CGPDFDictionaryGetDictionary(annotDict, "A", &aDict)) {
            return;
        }

        CGPDFStringRef uriStringRef;
        if(!CGPDFDictionaryGetString(aDict, "URI", &uriStringRef)) {
            return;
        }

        CGPDFArrayRef rectArray;
        if(!CGPDFDictionaryGetArray(annotDict, "Rect", &rectArray)) {
            return;
        }

        int arrayCount = CGPDFArrayGetCount( rectArray );
        CGPDFReal coords[4];
        for( int k = 0; k < arrayCount; ++k ) {
            CGPDFObjectRef rectObj;
            if(!CGPDFArrayGetObject(rectArray, k, &rectObj)) {
                return;
            }

            CGPDFReal coord;
            if(!CGPDFObjectGetValue(rectObj, kCGPDFObjectTypeReal, &coord)) {
                return;
            }

            coords[k] = coord;
        }               

        char *uriString = (char *)CGPDFStringGetBytePtr(uriStringRef);

        NSString *uri = [NSString stringWithCString:uriString encoding:NSUTF8StringEncoding];
        CGRect rect = CGRectMake(coords[0],coords[1],coords[2],coords[3]);

        CGPDFInteger pageRotate = 0;
        CGPDFDictionaryGetInteger( pageDictionary, "Rotate", &pageRotate ); 
        CGRect pageRect = CGRectIntegral( CGPDFPageGetBoxRect( thisPage, kCGPDFMediaBox ));
        if( pageRotate == 90 || pageRotate == 270 ) 
        {
            CGFloat temp = pageRect.size.width;
            pageRect.size.width = pageRect.size.height;
            pageRect.size.height = temp;
        }

        rect.size.width -= rect.origin.x;
        rect.size.height -= rect.origin.y;

        CGAffineTransform trans = CGAffineTransformIdentity;
        trans = CGAffineTransformTranslate(trans, 0, pageRect.size.height);
        trans = CGAffineTransformScale(trans, 1.0, -1.0);

        rect = CGRectApplyAffineTransform(rect, trans);

        UIButton *btnTmp = [UIButton buttonWithType:UIButtonTypeRoundedRect]; // After testing put here UIButtonTypeCustom
        [btnTmp addTarget:self action:@selector(urlOpen:) forControlEvents:UIControlEventTouchUpInside];
        rect.origin.x = rect.origin.x + 78; //I have adjusted this as per my requirement
        rect.origin.y = rect.origin.y + 108; // I have adjusted this as per my requirement
        btnTmp.frame = rect;
        btnTmp.titleLabel.text = uri;
        [self.superview addSubview:btnTmp];
    }
}